Insect ecdysone steroid hormone regulates major developmental transitions, such as molting and metamorphosis. The production of ecdysone correlates well with the timing of these transitions. Finding out how the ecdyso...Insect ecdysone steroid hormone regulates major developmental transitions, such as molting and metamorphosis. The production of ecdysone correlates well with the timing of these transitions. Finding out how the ecdysone biosynthesis is regulated is crucial to fully understand these sophisticated developmental switches. Here we summarized recent findings in the regulation of ecdysone biosynthesis from the aspects of cell signaling, key biosynthetic enzymes and substrate cholesterol trafficking.展开更多
Effects of the mixture of β-ecdysone and polypodine -B (2 : 1 W/W) on the moulting and growth of prawn, Penaeus orientaliss were studied in laboratory by rearing the animal with the added compound diets. The results ...Effects of the mixture of β-ecdysone and polypodine -B (2 : 1 W/W) on the moulting and growth of prawn, Penaeus orientaliss were studied in laboratory by rearing the animal with the added compound diets. The results showed that the addition of the moulting hormone (M. H) mixture to compound diets, from 1. 33× 10-6 to 30×10-6, could increase moulting activity and growth rate of the prawn to different extents, among which the 5. 33× 10-6-10. 67×10-6addition had statistically significant effects. However, 60 × 10-6 added diets caused moulting and growth inhibitions and cuticle thickening. The analyses of protein, water and ash contents of the prawn showed no remarkable differences between hormone dosed animals and the control.展开更多
Metamorphosis is a complex developmental process involving multiple pathways and a large number of genes that are regulated by juvenile hormone(JH)and 20-hydroxyecdysone(20E).Despite important progress in understandin...Metamorphosis is a complex developmental process involving multiple pathways and a large number of genes that are regulated by juvenile hormone(JH)and 20-hydroxyecdysone(20E).Despite important progress in understanding various aspects of silkworm biology,the hormone signaling pathway in the silkworm remains poorly understood.Genome-wide screening using clustered regularly interspaced short palindromic repeats(CRISPR)/CRISPR-associated protein 9(Cas9)-based libraries has recently emerged as a novel method for analyzing genome function,enabling further research into essential genes,drug targets,and virus-host interaction.Previously,we constructed a genome-wide CRISPR/Cas9-based library of the silkworm(Bombyx mori)and successfully revealed the genes involved in biotic or abiotic stress factor responses.In this study,we used our silkworm CRISPR library and large-scale genome-wide screening to analyze the key genes in the silkworm 20E signaling pathway and their mechanisms of action.Functional annotation showed that 20E regulates key proteins in processes that mainly occur in the cytoplasm and nucleus.Pathway enrichment analysis showed that 20E can activate phosphorylation and may affect innate immunity,interfere with intracellular nutrition and energy metabolism,and eventually cause cell apoptosis.The screening results were experimentally validated by generating cells with knockout alleles of the relevant genes,which had increased tolerance to 20E.Our findings provide a panoramic overview of signaling in response to 20E in the silkworm,underscoring the utility of genome-wide CRISPR mutant libraries in deciphering hormone signaling pathways and the mechanisms that regulate metamorphosis in insects.展开更多
A high-performance liquid chromatography coupled with an evaporative light scattering detector(HPLC-ELSD)has been developed to evaluate the quality of Asparagus filicinus through a simultaneous determination of six st...A high-performance liquid chromatography coupled with an evaporative light scattering detector(HPLC-ELSD)has been developed to evaluate the quality of Asparagus filicinus through a simultaneous determination of six steroidal saponins and one ecdysone,including aspafiliosides A,B,C,E,G,filiasparoside A and 20-hydroxyecdysone.With a C_(18) analytical column,the seven analytes were separated efficiently using acetonitrile-water as the mobile phase in a gradient program.The method limits of detection ranged 0.1250.225μg,and the method limits of quantitation ranged 0.408-0.720μg,respectively.The intra-and inter-day precisions of the method were evaluated and were all less than 3%.All the recoveries for the spiked analytes ranged 95.16%-100.61%.The proposed method was succesfully applied to quantify the seven components in thirteen samples from different localities in China.展开更多
MicroRNAs (miRNAs) regulate various biological processes during insect developme nt;however, their role in larval-pupal development in oriental fruit fly, Bactrocera dorsalis (Hendel) remains unknown. In the current s...MicroRNAs (miRNAs) regulate various biological processes during insect developme nt;however, their role in larval-pupal development in oriental fruit fly, Bactrocera dorsalis (Hendel) remains unknown. In the current study, we address the biological function of a conserved miRNA, Bdo-Let-7 in the regulation of BdE75 gene, which belongs to the ecdysone signaling pathway and participates in the larval-pupal development in B. dorsalis. Using dual luciferase reporter assay in HEK293T cells we show that Bdo-Let-7 miRNA interacts with the 3' untranslated region of BdE75 gene and suppresses its expression. The Bdo-Let?7 and BdE75 are also co-expressed in the larval-pupal stages and in different tissues of B. dorsalis .In in vivo experiments, the injectio n of Bdo-Let-7 agomir and antagomir in third instar larvae down- and up-regulated the expression of BdE75、 respectively. The 20-hydroxyecdysone (20E) injection assay shows that 20E up-regulated the expression of Bdo-Let-7 on the 5th day of the larvae. Moreover, abnormal pupation and eclosion were observed after larval Bdo-Let-7 antagomir injection. Based on these results, we show that Bdo-Let-7 regulates the ecdysone signaling pathway through the exact dose of BdE75 gene, and is indispensable for normal larval-pupal development in B. dorsalis.展开更多
Metamorphosis is one of the most important physiological processes in insects.It is regulated by a serial of ecdysone cascade genes.Recently,lots o f microRNAs(miRNAs)were investigated in insects;however,their functio...Metamorphosis is one of the most important physiological processes in insects.It is regulated by a serial of ecdysone cascade genes.Recently,lots o f microRNAs(miRNAs)were investigated in insects;however,their function in metamorphosis is largely unknown.In the present study,the dynamics of a small RNA population was investigated by RNA sequencing from the midgut of a lepidopteran pest Spodoptera litura during larval-pupal metamorphosis.A total of 101 miRNAs were identified,and 75 miRNAs were differentially expressed during the metamorphic process.The relationship between these differentially expressed miRNAs and 12 ecdysone cascade genes was analyzed by four classical software programs,and a multiple-to-multiple regulatory network was found to exist between these miRNAs and their targets.Among them,miR-14-3p and its two targets(EcR and E75)were chosen for further validation.MiR-14-3p had higher expression level in the 6 th instar larvae as compared with either the prepupae or pupae,which was opposite to that of both EcR and E75,two ecdysone cascade genes.Luciferase reporter assay confirmed that both EcR and E75 were regulated by miR-14-3p.Interestingly,the 3'untranslated regions are nearly identical to each other among different transcript variants of the ecdysone cascade genes,including EcR,USP,E75,E74,E78,E93,Hr3,Hr4,Hr39,K rhl and F tzfl.Thus,different transcript variants of one ecdysone cascade gene could be regulated by the same mi RNA.The above data suggest that the ecdysone signaling pathway is under the tight control of miRNA.These findings expand our understanding of the mechanism of insect metamorphosis and may also provide a novel possibility for the control of pest insects in the future.展开更多
Henosepilachna vigintioctopunctata is a serious insect pest which attacks a large number of nightshades and cucurbits in Asian countries,Brazil and Australia.Prolonged application of traditional pesticides has caused ...Henosepilachna vigintioctopunctata is a serious insect pest which attacks a large number of nightshades and cucurbits in Asian countries,Brazil and Australia.Prolonged application of traditional pesticides has caused environmental pollution and exerted deleterious effects on human health.Finding new approaches with high target specificity and low environmental contamination has become an urgent task.RNA interference(RNAi)induced by double-stranded RNA(dsRNA)is expected to be applicable to managing this pest.Here we evaluated the effects of Escherichia co/Z-expressed dsRNAs targeting ecdvsone receptor(EcR)gene via dietary delivery in laboratory and foliar spraying in a greenhouse.The target transcript was successfully knocked down when the 4th-instar larvae had fed on potatofoliage dipped with dsEcR in a laboratory bioassay.Around 85%of the HvEcR RNAi larvae remained as prepupae or became abnormal pupae,and failed to emerge into adults.Ingestion of ds£c7?-immersed foliage by the 3rd-instar larvae effectuated a comparable RNAi response and brought about more severe defects:all the resultant larvae arrested development,remained as prepupae and finally died.For assay in the greenhouse,a ds£c7?-contained E.coli suspension was directly sprayed to the foliage of greenhouse-growing potato plants and the 3rd-and 4th-instar larvae were transferred to the leaves.High RNAi efficacy was obtained and identical RNAi phenotypes were observed in treated larvae.In addition,spraying dsEcR reduced leaf damage.Our results indicate a possibility of practical application of dsEcR as an environmentally friendly RNA pesticide to control H.vigintioctopunctata larvae.展开更多
A heterodimer of two nuclear receptors,ecdysone receptor(EcR)and ultraspiracle,mediates 20‐hydroxyecdysone(20E)signaling to modulate many aspects in insect life,such as molting and metamorphosis,reproduction,diapause...A heterodimer of two nuclear receptors,ecdysone receptor(EcR)and ultraspiracle,mediates 20‐hydroxyecdysone(20E)signaling to modulate many aspects in insect life,such as molting and metamorphosis,reproduction,diapause and innate immunity.In the present paper,we intended to determine the isoform‐specific roles of EcR during larval–pupal–adult transition in the Colorado potato beetle.Double‐stranded RNAs(dsRNAs)were prepared using the common(dsEcR)or isoform‐specific(dsEcRA,dsEcRB1)regions of EcR as templates.Ingestion of either dsEcR or dsEcRA,rather than dsEcRB1,by the penultimate(3rd)and final(4th)instar larvae caused failure of larval–pupal and pupal–adult ecdysis.The RNA interference(RNAi)larvae remained as prepupae,or became deformed pupae and adults.Determination of messenger RNA(mRNA)levels of EcR isoforms found that LdEcRA regulates the expression of LdEcRB1.Moreover,silencing the two EcR transcripts,LdEcRA or LdEcRB1 reduced the mRNA levels of Ldspo and Ldsad,and lowered 20E titer.In contrast,the expression levels of HR3,HR4,E74 and E75 were significantly decreased in the LdEcR or LdEcRA RNAi larvae,but not in LdEcRB1 depleted specimens.Dietary supplement with 20E did not restore the expression of five 20E signaling genes(USP,HR3,HR4,E74 and E75),and only partially alleviated the pupation defects in dsEcR‐or dsEcRA‐fed beetles.These data suggest that EcR plays isoform‐specific roles in the regulation of ecdysteroidogenesis and the transduction of 20E signal in L.decemlineata.展开更多
Body size is one of the features that distinguish one species from another in the biological world. Animals have developed mechanisms to control their body size during normal development. However, how animals cope wit...Body size is one of the features that distinguish one species from another in the biological world. Animals have developed mechanisms to control their body size during normal development. However, how animals cope with genetic alterations and/or environmental stresses to develop into normal-sized adults remain poorly understood. The ability of the animals to develop into a normal-sized adult after the challenges of genetic alterations and/or environmental stresses reveals a robustness of body size control. Here we show that the mutation of dGPAT4, a de novo synthase of lysophosphatidic acid, is a genetic alteration that triggers such a robust response of the animals to body size challenges in Drosophila. Loss of dGPAT4 leads to a severe delay of development, slow growth and resultant small-sized animals during the larval stages, but results in normal-sized adult flies. The robust body size adjustment of the dGPAT4 mutant is likely achieved by corresponding changes in ecdysone and insulin signaling, which is also manifested by compromised food intake. Thus, we propose that a strategy has been evolved by the animals to reach final body size when challenged by genetic alterations, which requires the coordinated ecdysone and insulin signaling.展开更多
Cholesterol,as an indispensable nutrient,regulates molting and growth in crustacean.As crustaceans are unable to biosynthesize cholesterol de novo,it is central to understand how dietary cholesterol affects molting in...Cholesterol,as an indispensable nutrient,regulates molting and growth in crustacean.As crustaceans are unable to biosynthesize cholesterol de novo,it is central to understand how dietary cholesterol affects molting in crustaceans.An 8-week feeding trial was conducted to evaluate the effects of dietary cholesterol level(0.12%,0.43%,0.79%,1.00%,1.30%and 2.50%)on growth,cholesterol metabolism and expression of genes related to lipid and ecdysone metabolism in female swimming crabs(Portunus trituberculatus).A total of 192 crabs(1.41±0.05 g)were randomly distributed into 192 aquaria.Each treatment had 4 replicates with each replicate containing 8 crabs.Crabs fed the 1.00%cholesterol diet showed best growth performance,and thus based on percent weight gain,the optimal dietary cholesterol requirement was calculated at 1.01%.Tissue cholesterol concentrations were positively correlated with dietary cholesterol level.The contents of functional fatty acids in hepatopancreas significantly increased as dietary cholesterol increased from 0.12%to 2.50%(P<0.05).The expression levels of genes related to lipogenesis pathway,lipid catabolism and fatty acid oxidation were significantly downregulated with increased dietary cholesterol level(P<0.05).The highest expression levels of cholesterol transport genes,low-density lipoprotein receptor(ldlr)and low-density lipoprotein receptorrelated protein 2(lrp2)occurred in crabs fed the 1.30%cholesterol diet.Moreover,hormones related to molting such as crustacean hyperglycemic hormone(CHH),methyl farnesoate(MF),molt-inhibiting hormone(MIH),and ecdysone in hemolymph were significantly influenced by dietary cholesterol level(P<0.05).The highest expression levels of ecdysone receptor(ecr)and chitinase 1(chi1)in eyestalk and hepatopancreas were found in crabs fed the diet containing 1.00%cholesterol(P<0.05).In conclusion,the optimal dietary level was beneficial to functional fatty acid accumulation,regulated lipid metabolism,promoted the ecdysone signalling pathway by improving the cholesterol transport,and improved the molting rate and growth of swimming crabs.展开更多
Metazoan development requires coordination of signaling pathways to regulate patterns of gene expression.In Drosophila,the wing imaginal disc provides an excellent model for the study of how signaling pathways interac...Metazoan development requires coordination of signaling pathways to regulate patterns of gene expression.In Drosophila,the wing imaginal disc provides an excellent model for the study of how signaling pathways interact to regulate pattern formation.The determination of the dorsal-ventral（DV） boundary of the wing disc depends on the Notch pathway,which is activated along the DV boundary and induces the expression of the homeobox transcription factor,Cut.Here,we show that Broad（Br）,a zinc-finger transcription factor,is also involved in regulating Cut expression in the DV boundary region.However,Br expression is not regulated by Notch signaling in wing discs,while ecdysone signaling is the upstream signal that induces Br for Cut upregulation.Also,we find that the ecdysone-Br cascade upregulates cut-lacZ expression,a reporter containing a 2.7 kb cut enhancer region,implying that ecdysone signaling,similar to Notch,regulates cut at the transcriptional level.Collectively,our findings reveal that the Notch and ecdysone signaling pathways synergistically regulate Cut expression for proper DV boundary formation in the wing disc.Additionally,we show br promotes Delta,a Notch ligand,near the DV boundary to suppress aberrant high Notch activity,indicating further interaction between the two pathways for DV patterning of the wing disc.展开更多
Lycosidae females demonstrate meticulous maternal care of offspring by carrying egg sacs and juvenile spiderlings during the reproductive stage. Nuclear receptors(NRs), especially the ecdysone receptor(EcR) and ultras...Lycosidae females demonstrate meticulous maternal care of offspring by carrying egg sacs and juvenile spiderlings during the reproductive stage. Nuclear receptors(NRs), especially the ecdysone receptor(EcR) and ultraspiracle(USP), have attracted considerable attention in the regulation of arthropod development and reproduction due to their pivotal roles in ecdysteroid signaling cascades. In the present study, 23 NRs, including one EcR and two USPs, were identified in the genome of the predatory wolf spider Pardosa pseudoannulata. RNA interference(RNAi) targeting EcR and USP-1inhibited spiderling development and resulted in nonviable eggs in the egg sacs. EcR and USP-1responded to changes in ecdysteroid levels, and interference in ecdysteroid biosynthesis led to similar phenotypes as ds EcR and ds USP-1 treatments.These findings suggest that EcR/USP-1-mediated ecdysteroid signaling regulates P. pseudoannulata development and reproduction. The P.pseudoannulata females with suppressed ecdysteroid signaling proactively consumed their non-viable egg sacs, resulting in a 7.19 d shorter first reproductive cycle than the controls. Termination of the failed reproductive cycle enabled the spiders to produce a new egg sac more rapidly. This reproductive strategy may partially rescue the reduction in population growth due to non-viable eggs and compensate for the physiological expenditure of wasted maternal care, which would be beneficial for the conservation of P.pseudoannulata populations and their natural control of insect pests.展开更多
The brown planthopper(Nilaparvata lugens) is the main migratory pest in many rice growing areas in Asia. E78 is a member of the nuclear hormone receptor superfamily which plays an important role in egg development and...The brown planthopper(Nilaparvata lugens) is the main migratory pest in many rice growing areas in Asia. E78 is a member of the nuclear hormone receptor superfamily which plays an important role in egg development and maternal regulation of early embryogenesis. In this study, brown planthopper E78(NlE78) was cloned, and the predicted amino acid sequence showed that it contains two conserved domains: NR-LBD and DBD. qRT-PCR showed that the expression of NlE78 is high in the fifth instar nymphs and the ovaries of females. After downregulation of NlE78, the rate of moulting failure(33.2%) increased significantly, and ovarian development was delayed. However, when NlE78was downregulated together with NlE93, the emergence rate increased significantly(78.79%), and ovarian development was similar to that when NlE78 was downregulated but not delayed. A co-immunoprecipitation experiment showed that NlE78 interacts with NlE93, a crucial downstream transcription factor of the ecdysone signalling pathway. Cellular localization by immunofluorescence revealed that NlE78 and NlE93 are expressed in the nucleus. This study indicates that NlE78 regulates ovarian development and moulting, possibly through its interaction with NlE93. This study is of great significance for the development of new pesticides and control methods based on newly discovered targets.展开更多
Ecdysteroids play an important role in regulating diverse physiological processes in arthropods,such as molting,metamorphosis,reproduction and diapause.Ecdysteroids mediate the response by binding to a heterodimeric c...Ecdysteroids play an important role in regulating diverse physiological processes in arthropods,such as molting,metamorphosis,reproduction and diapause.Ecdysteroids mediate the response by binding to a heterodimeric complex of two nuclear receptors:the ecdysone receptor and the ultraspiracle(USP).To investigate the role of USP in development of the Asian gypsy moth(Lymantria dispar),a USP cDNA was obtained from the transcriptome of L.dispar and verified by PCR.In-depth profiling of transcript levels of L.dispar USP-1(LdUSP-1)at different developmental stages and over time in thirdinstar larvae and different tissues isolated during the thirdinstar stage of L.dispar was then carried out.Transcript levels of LdUSP-1 were relatively high before 72 h in the third-instar larvae after ecdysis and in the adult male.The function of LdUSP-1 in molting was analyzed by knockdown of LdUSP-1 in third instar larvae using RNA interference.Silencing of LdUSP-1 significantly downregulated the transcript level of E75,an ecdysone-inducible gene,and of Sad,a Halloween gene.In addition,the duration of the third-instar stage was slightly shortened and larval mortality increased after the LdUSP-1 knockdown.展开更多
Anautogenous mosquitoes must blood feed on a vertebrate host to produce eggs.Each gonadotrophic cycle is subdivided into a sugar-feeding previtellogenic phase that produces primary follicles and a blood meal-activated...Anautogenous mosquitoes must blood feed on a vertebrate host to produce eggs.Each gonadotrophic cycle is subdivided into a sugar-feeding previtellogenic phase that produces primary follicles and a blood meal-activated vitellogenic phase in which large numbers of eggs synchronously mature and are laid.Multiple endocrine factors including juvenile hormone(JH),insulin-like peptides(ILPs),ovary ecdysteroidogenic hormone(OEH),and 20-hydroxyecdysone(20E)coordinate each gonadotrophic cycle.Egg formation also requires nutrients from feeding that are stored in the fat body.Regulation of egg formation is best understood in Aedes aegypti but the role different endocrine factors play in regulating nutrient mobilization and storage remains unclear.In this study,we report that adult female Ae.aegypti maintained triacylglycerol(TAG)stores during the previtellogenic phase of the first gonadotrophic cycle while glycogen stores declined.In contrast,TAG and glycogen stores were rapidly mobilized during the vitellogenic phase and then replenishment.Several genes encoding enzymes with functions in TAG and glycogen metabolism were differentially expressed in the fat body,which suggested regulation was mediated in part at the transcriptional level.Gain of function assays indicated that stored nutrients were primarily mobilized by adipokinetic hormone(AKH)while juvenoids and OEH regulated replenishment.ILP3 further showed evidence of negatively regulating certain lipolytic enzymes.Loss of function assays indicated AKH depends on the AKH receptor(AKHR)for function.Altogether,our results indicate that the opposing activities of different hormones regulate nutrient stores during a gonadotrophic cycle in Ae.aegypti.展开更多
The paradigm, still around in textbooks, that ＇in insects sex is strictly genetic, thus that they do not have sex hormones＇, is mainly based on a wrong interpretation of the ＇gynandromorph argument＇. It is no long...The paradigm, still around in textbooks, that ＇in insects sex is strictly genetic, thus that they do not have sex hormones＇, is mainly based on a wrong interpretation of the ＇gynandromorph argument＇. It is no longer tenable. Given the fact that vertebrates and invertebrates probably had a common, sexually reproducing ancestor, there is no reason to assume that only vertebrates need sex hormones. The major function of sex hormones is to inform the somatoplasm about developmental changes that take place in the gonads. In contrast to juvenile hormone and neuropeptides, ecdysteroids meet all criteria to act as sex hormones, which was probably their ancient role. Their much better documented role in moulting and metamorphosis was a secondary acquisition that enabled arthropods to cope with growth problems, imposed by a rigid cuticle. Female insects use 20-hydroxyecdysone （20E）, secreted by the follicle cells of the ovary, in a similar way as females of egg-laying vertebrates use estrogens. For a variety of reasons, the possibility that ecdysteroids, in particular ecdysone （E）, might also act as sex hormones in male insects, thus as the counterpart of testosterone of vertebrates, has been very much overlooked. Thanks to the recent discovery of the molecular basis of the haploid-diploid system of sex determination in the honeybee, the characterization of Halloween genes, proteomics, RNAi and so on, it now becomes possible to verify whether in insects, as with vertebrates, males are the endocrinologically default gender form.展开更多
Ecdysone receptor （EcR） and ultraspiracle （USP） form heterodimers to mediate ecdysteroid signaling during molting and metamorphosis. Various EcR/USP heterodimers have been reported. However, it is unclear what kin...Ecdysone receptor （EcR） and ultraspiracle （USP） form heterodimers to mediate ecdysteroid signaling during molting and metamorphosis. Various EcR/USP heterodimers have been reported. However, it is unclear what kind of EcR/USP combination is adopted by lepidopteran insects during the larval-pupal metamorphosis and whether the EcR/USP heterodimer varies among different tissues. To address these questions, two isoforms of each EcR and USP were cloned from the common cutworm, their messenger RNA expression patterns were examined by real-time quantitative polymerase chain reaction in different tissues during the larval-pupal metamorphosis and in the midgut in response to hormonal induction. Furthermore, their subcellular localization and protein-protein interaction were explored by transient expression and far-western blotting, respectively. All the four genes were significantly up-regulated in prepuae and/or pupae. The expression profiles of EcRB1 and USP1 were nearly identical to each other in the epidermis, fat body and midgut, and a similar situation also applied to EcRA and USP2. The three genes responded to 20-hydroxyecdysone （20E） induction except for USP2, and USP1 could be up-regulated by both 20E and juvenile hormone. The four proteins mainly localized in the nucleus and the nuclear localization was promoted by 20E. The protein-protein interaction between each EcR and USP was found in vitro. These results suggest that two types of EcR/USP heterodimer （EeRA/USP2 and EcRB 1/USP1） may exist simultaneously in the common cutworm, and the latter should play more important roles during the larval-pupal metamorphosis. In addition, the types of EcR/USP heterodimer do not vary in the tissues which undergo histolysis and regeneration during metamorphosis.展开更多
Spider mites have one ecdysone receptor(EcR)and multiple retinoid X receptors(RXRs).However,the function of these RXRs in spider mite development is unknown.Here,we screened the expression dynamics of two PcRXR isofor...Spider mites have one ecdysone receptor(EcR)and multiple retinoid X receptors(RXRs).However,the function of these RXRs in spider mite development is unknown.Here,we screened the expression dynamics of two PcRXR isoforms at 4 h intervals in the deutonymphal stage of Panonychus citri.The results showed that PcEcR had an expression pattern similar to that of PcRXR2.For PcRXR1,its expression remained at a certain high level,when there was a decrease of both PcEcR and PcRXR2.In situ hybridization showed that PcRXR2 was detected in the central nervous mass,while the ecdysteroid biosynthesis gene PcSpo was mainly expressed at the edge of the central nervous mass.RNAi-based silencing of PcRXR1 or PcRXR2 showed the same phenotype as in mites with that of silencing PcEcR.Furthermore,RNA-seq was used to mine the genes associated with the expression dynamics of PcRXR1 or PcRXR2,which revealed that the heterodimer of EcR-RXR2 in spider mites might be linked with the cell autophagy and tissue remodeling during apolysis,and RXR1 might be linked with new epicuticle and exocuticle secretion during ecdysis.Taken together,these results increase our understanding of the regulation mechanism of ecdysteroid signal pathway in spider mite development.展开更多
U1 small nuclear ribonucleoproteins(U1 snRNP)associates with 5ʹsplice sites in the form of ribonucleoprotein particles and is highly conserved among species.The physiological functions of U1 snRNP in a lepidopteran mo...U1 small nuclear ribonucleoproteins(U1 snRNP)associates with 5ʹsplice sites in the form of ribonucleoprotein particles and is highly conserved among species.The physiological functions of U1 snRNP in a lepidopteran model insect Bombyx mori is mostly unknown.Here,we showed that U1 snRNP plays an important role in the development of silkworm.Knockout of U1 snRNP in silkworm showed either delayed or stationary 1st instar larva development compared with the wild-type group.U1 snRNP deletion mutants exhibited abnormal cellular phenotypes with enlarged cell nucleus,scant cytoplasm and enlarged nuclei.RNA-seq analysis revealed that genes involved in metabolic pathway,biosynthesis of secondary metabolites and steroid hormone biosynthesis were significantly affected by U1 snRNP depletion.Taken together,our study suggests that U1 snRNP homeostasis plays an important role in silkworm development.展开更多
基金This work was supported by grant 0516623 to L.I.G. and J.T.W. from the National Science Foundation.
文摘Insect ecdysone steroid hormone regulates major developmental transitions, such as molting and metamorphosis. The production of ecdysone correlates well with the timing of these transitions. Finding out how the ecdysone biosynthesis is regulated is crucial to fully understand these sophisticated developmental switches. Here we summarized recent findings in the regulation of ecdysone biosynthesis from the aspects of cell signaling, key biosynthetic enzymes and substrate cholesterol trafficking.
文摘Effects of the mixture of β-ecdysone and polypodine -B (2 : 1 W/W) on the moulting and growth of prawn, Penaeus orientaliss were studied in laboratory by rearing the animal with the added compound diets. The results showed that the addition of the moulting hormone (M. H) mixture to compound diets, from 1. 33× 10-6 to 30×10-6, could increase moulting activity and growth rate of the prawn to different extents, among which the 5. 33× 10-6-10. 67×10-6addition had statistically significant effects. However, 60 × 10-6 added diets caused moulting and growth inhibitions and cuticle thickening. The analyses of protein, water and ash contents of the prawn showed no remarkable differences between hormone dosed animals and the control.
基金This work was supported by grants from the National Natural Science Foundation of China(No.32122084)Chongqing Natural Science Foundation(No.cstc2021ycjh-bgzxm0005)+1 种基金PhD Start-Up Foundation of Southwest University(No.SWU120012)Fundamental Research Funds for the Central Universities(No.SWU-KT22042).None of these fundings played any role in the design of the study,collection,analysis,or interpretation of data or in the writing of the manuscript.
文摘Metamorphosis is a complex developmental process involving multiple pathways and a large number of genes that are regulated by juvenile hormone(JH)and 20-hydroxyecdysone(20E).Despite important progress in understanding various aspects of silkworm biology,the hormone signaling pathway in the silkworm remains poorly understood.Genome-wide screening using clustered regularly interspaced short palindromic repeats(CRISPR)/CRISPR-associated protein 9(Cas9)-based libraries has recently emerged as a novel method for analyzing genome function,enabling further research into essential genes,drug targets,and virus-host interaction.Previously,we constructed a genome-wide CRISPR/Cas9-based library of the silkworm(Bombyx mori)and successfully revealed the genes involved in biotic or abiotic stress factor responses.In this study,we used our silkworm CRISPR library and large-scale genome-wide screening to analyze the key genes in the silkworm 20E signaling pathway and their mechanisms of action.Functional annotation showed that 20E regulates key proteins in processes that mainly occur in the cytoplasm and nucleus.Pathway enrichment analysis showed that 20E can activate phosphorylation and may affect innate immunity,interfere with intracellular nutrition and energy metabolism,and eventually cause cell apoptosis.The screening results were experimentally validated by generating cells with knockout alleles of the relevant genes,which had increased tolerance to 20E.Our findings provide a panoramic overview of signaling in response to 20E in the silkworm,underscoring the utility of genome-wide CRISPR mutant libraries in deciphering hormone signaling pathways and the mechanisms that regulate metamorphosis in insects.
基金This investigation was supported by the grants from the Science and Technology Commission of Shanghai Municipality(04DZ19806)the Natural Science Foundation of China(30925042)the State Key Program from the Ministry of Science and Technology,China(2009ZX09502-013).
文摘A high-performance liquid chromatography coupled with an evaporative light scattering detector(HPLC-ELSD)has been developed to evaluate the quality of Asparagus filicinus through a simultaneous determination of six steroidal saponins and one ecdysone,including aspafiliosides A,B,C,E,G,filiasparoside A and 20-hydroxyecdysone.With a C_(18) analytical column,the seven analytes were separated efficiently using acetonitrile-water as the mobile phase in a gradient program.The method limits of detection ranged 0.1250.225μg,and the method limits of quantitation ranged 0.408-0.720μg,respectively.The intra-and inter-day precisions of the method were evaluated and were all less than 3%.All the recoveries for the spiked analytes ranged 95.16%-100.61%.The proposed method was succesfully applied to quantify the seven components in thirteen samples from different localities in China.
基金the earmarked fund for the China Agricultural Research System (No. CARS-26)International Atomic Energy Agency's Coordinated Research Project (No. D42016)+1 种基金the National Natural Science Foundation of China (No. 31572008)Fundamental Research Funds for the Central Universities (No. 2014PY005 and 2662015PY129).
文摘MicroRNAs (miRNAs) regulate various biological processes during insect developme nt;however, their role in larval-pupal development in oriental fruit fly, Bactrocera dorsalis (Hendel) remains unknown. In the current study, we address the biological function of a conserved miRNA, Bdo-Let-7 in the regulation of BdE75 gene, which belongs to the ecdysone signaling pathway and participates in the larval-pupal development in B. dorsalis. Using dual luciferase reporter assay in HEK293T cells we show that Bdo-Let-7 miRNA interacts with the 3' untranslated region of BdE75 gene and suppresses its expression. The Bdo-Let?7 and BdE75 are also co-expressed in the larval-pupal stages and in different tissues of B. dorsalis .In in vivo experiments, the injectio n of Bdo-Let-7 agomir and antagomir in third instar larvae down- and up-regulated the expression of BdE75、 respectively. The 20-hydroxyecdysone (20E) injection assay shows that 20E up-regulated the expression of Bdo-Let-7 on the 5th day of the larvae. Moreover, abnormal pupation and eclosion were observed after larval Bdo-Let-7 antagomir injection. Based on these results, we show that Bdo-Let-7 regulates the ecdysone signaling pathway through the exact dose of BdE75 gene, and is indispensable for normal larval-pupal development in B. dorsalis.
基金grants from the National Natural Science Foundation of China(Grant No.31672357 and 31872285)。
文摘Metamorphosis is one of the most important physiological processes in insects.It is regulated by a serial of ecdysone cascade genes.Recently,lots o f microRNAs(miRNAs)were investigated in insects;however,their function in metamorphosis is largely unknown.In the present study,the dynamics of a small RNA population was investigated by RNA sequencing from the midgut of a lepidopteran pest Spodoptera litura during larval-pupal metamorphosis.A total of 101 miRNAs were identified,and 75 miRNAs were differentially expressed during the metamorphic process.The relationship between these differentially expressed miRNAs and 12 ecdysone cascade genes was analyzed by four classical software programs,and a multiple-to-multiple regulatory network was found to exist between these miRNAs and their targets.Among them,miR-14-3p and its two targets(EcR and E75)were chosen for further validation.MiR-14-3p had higher expression level in the 6 th instar larvae as compared with either the prepupae or pupae,which was opposite to that of both EcR and E75,two ecdysone cascade genes.Luciferase reporter assay confirmed that both EcR and E75 were regulated by miR-14-3p.Interestingly,the 3'untranslated regions are nearly identical to each other among different transcript variants of the ecdysone cascade genes,including EcR,USP,E75,E74,E78,E93,Hr3,Hr4,Hr39,K rhl and F tzfl.Thus,different transcript variants of one ecdysone cascade gene could be regulated by the same mi RNA.The above data suggest that the ecdysone signaling pathway is under the tight control of miRNA.These findings expand our understanding of the mechanism of insect metamorphosis and may also provide a novel possibility for the control of pest insects in the future.
基金This research was supported by the N ational Key R&D Program of China(2017YFD0200900)China A griculture Research System(CARS-09-P22).
文摘Henosepilachna vigintioctopunctata is a serious insect pest which attacks a large number of nightshades and cucurbits in Asian countries,Brazil and Australia.Prolonged application of traditional pesticides has caused environmental pollution and exerted deleterious effects on human health.Finding new approaches with high target specificity and low environmental contamination has become an urgent task.RNA interference(RNAi)induced by double-stranded RNA(dsRNA)is expected to be applicable to managing this pest.Here we evaluated the effects of Escherichia co/Z-expressed dsRNAs targeting ecdvsone receptor(EcR)gene via dietary delivery in laboratory and foliar spraying in a greenhouse.The target transcript was successfully knocked down when the 4th-instar larvae had fed on potatofoliage dipped with dsEcR in a laboratory bioassay.Around 85%of the HvEcR RNAi larvae remained as prepupae or became abnormal pupae,and failed to emerge into adults.Ingestion of ds£c7?-immersed foliage by the 3rd-instar larvae effectuated a comparable RNAi response and brought about more severe defects:all the resultant larvae arrested development,remained as prepupae and finally died.For assay in the greenhouse,a ds£c7?-contained E.coli suspension was directly sprayed to the foliage of greenhouse-growing potato plants and the 3rd-and 4th-instar larvae were transferred to the leaves.High RNAi efficacy was obtained and identical RNAi phenotypes were observed in treated larvae.In addition,spraying dsEcR reduced leaf damage.Our results indicate a possibility of practical application of dsEcR as an environmentally friendly RNA pesticide to control H.vigintioctopunctata larvae.
文摘A heterodimer of two nuclear receptors,ecdysone receptor(EcR)and ultraspiracle,mediates 20‐hydroxyecdysone(20E)signaling to modulate many aspects in insect life,such as molting and metamorphosis,reproduction,diapause and innate immunity.In the present paper,we intended to determine the isoform‐specific roles of EcR during larval–pupal–adult transition in the Colorado potato beetle.Double‐stranded RNAs(dsRNAs)were prepared using the common(dsEcR)or isoform‐specific(dsEcRA,dsEcRB1)regions of EcR as templates.Ingestion of either dsEcR or dsEcRA,rather than dsEcRB1,by the penultimate(3rd)and final(4th)instar larvae caused failure of larval–pupal and pupal–adult ecdysis.The RNA interference(RNAi)larvae remained as prepupae,or became deformed pupae and adults.Determination of messenger RNA(mRNA)levels of EcR isoforms found that LdEcRA regulates the expression of LdEcRB1.Moreover,silencing the two EcR transcripts,LdEcRA or LdEcRB1 reduced the mRNA levels of Ldspo and Ldsad,and lowered 20E titer.In contrast,the expression levels of HR3,HR4,E74 and E75 were significantly decreased in the LdEcR or LdEcRA RNAi larvae,but not in LdEcRB1 depleted specimens.Dietary supplement with 20E did not restore the expression of five 20E signaling genes(USP,HR3,HR4,E74 and E75),and only partially alleviated the pupation defects in dsEcR‐or dsEcRA‐fed beetles.These data suggest that EcR plays isoform‐specific roles in the regulation of ecdysteroidogenesis and the transduction of 20E signal in L.decemlineata.
基金financially supported by the grants from the National Natural Science Foundation of China (Nos. 81470846, 31271573 and 31228015)the National Basic Research Program of China (No. 2012CB825504)the Chinese Academy of Sciences (No. XDA04020413-02)
文摘Body size is one of the features that distinguish one species from another in the biological world. Animals have developed mechanisms to control their body size during normal development. However, how animals cope with genetic alterations and/or environmental stresses to develop into normal-sized adults remain poorly understood. The ability of the animals to develop into a normal-sized adult after the challenges of genetic alterations and/or environmental stresses reveals a robustness of body size control. Here we show that the mutation of dGPAT4, a de novo synthase of lysophosphatidic acid, is a genetic alteration that triggers such a robust response of the animals to body size challenges in Drosophila. Loss of dGPAT4 leads to a severe delay of development, slow growth and resultant small-sized animals during the larval stages, but results in normal-sized adult flies. The robust body size adjustment of the dGPAT4 mutant is likely achieved by corresponding changes in ecdysone and insulin signaling, which is also manifested by compromised food intake. Thus, we propose that a strategy has been evolved by the animals to reach final body size when challenged by genetic alterations, which requires the coordinated ecdysone and insulin signaling.
基金the National Natural Science Foundation of China(32072987)China Agriculture Research System-48(Supported by China Agriculture Research System of MOF and MARA)+1 种基金National Key R&D Program of China(2018YFD0900400)K.C.Wong Magna Fund in Ningbo University.
文摘Cholesterol,as an indispensable nutrient,regulates molting and growth in crustacean.As crustaceans are unable to biosynthesize cholesterol de novo,it is central to understand how dietary cholesterol affects molting in crustaceans.An 8-week feeding trial was conducted to evaluate the effects of dietary cholesterol level(0.12%,0.43%,0.79%,1.00%,1.30%and 2.50%)on growth,cholesterol metabolism and expression of genes related to lipid and ecdysone metabolism in female swimming crabs(Portunus trituberculatus).A total of 192 crabs(1.41±0.05 g)were randomly distributed into 192 aquaria.Each treatment had 4 replicates with each replicate containing 8 crabs.Crabs fed the 1.00%cholesterol diet showed best growth performance,and thus based on percent weight gain,the optimal dietary cholesterol requirement was calculated at 1.01%.Tissue cholesterol concentrations were positively correlated with dietary cholesterol level.The contents of functional fatty acids in hepatopancreas significantly increased as dietary cholesterol increased from 0.12%to 2.50%(P<0.05).The expression levels of genes related to lipogenesis pathway,lipid catabolism and fatty acid oxidation were significantly downregulated with increased dietary cholesterol level(P<0.05).The highest expression levels of cholesterol transport genes,low-density lipoprotein receptor(ldlr)and low-density lipoprotein receptorrelated protein 2(lrp2)occurred in crabs fed the 1.30%cholesterol diet.Moreover,hormones related to molting such as crustacean hyperglycemic hormone(CHH),methyl farnesoate(MF),molt-inhibiting hormone(MIH),and ecdysone in hemolymph were significantly influenced by dietary cholesterol level(P<0.05).The highest expression levels of ecdysone receptor(ecr)and chitinase 1(chi1)in eyestalk and hepatopancreas were found in crabs fed the diet containing 1.00%cholesterol(P<0.05).In conclusion,the optimal dietary level was beneficial to functional fatty acid accumulation,regulated lipid metabolism,promoted the ecdysone signalling pathway by improving the cholesterol transport,and improved the molting rate and growth of swimming crabs.
基金supported by Dissertation Research Grant Award from Florida State Universitysupported by the National Institutes of Health grant(R01GM072562)the National Science Foundation(IOS-1052333)
文摘Metazoan development requires coordination of signaling pathways to regulate patterns of gene expression.In Drosophila,the wing imaginal disc provides an excellent model for the study of how signaling pathways interact to regulate pattern formation.The determination of the dorsal-ventral（DV） boundary of the wing disc depends on the Notch pathway,which is activated along the DV boundary and induces the expression of the homeobox transcription factor,Cut.Here,we show that Broad（Br）,a zinc-finger transcription factor,is also involved in regulating Cut expression in the DV boundary region.However,Br expression is not regulated by Notch signaling in wing discs,while ecdysone signaling is the upstream signal that induces Br for Cut upregulation.Also,we find that the ecdysone-Br cascade upregulates cut-lacZ expression,a reporter containing a 2.7 kb cut enhancer region,implying that ecdysone signaling,similar to Notch,regulates cut at the transcriptional level.Collectively,our findings reveal that the Notch and ecdysone signaling pathways synergistically regulate Cut expression for proper DV boundary formation in the wing disc.Additionally,we show br promotes Delta,a Notch ligand,near the DV boundary to suppress aberrant high Notch activity,indicating further interaction between the two pathways for DV patterning of the wing disc.
基金supported by the National Natural Science Foundation of China(31972296,32172482)。
文摘Lycosidae females demonstrate meticulous maternal care of offspring by carrying egg sacs and juvenile spiderlings during the reproductive stage. Nuclear receptors(NRs), especially the ecdysone receptor(EcR) and ultraspiracle(USP), have attracted considerable attention in the regulation of arthropod development and reproduction due to their pivotal roles in ecdysteroid signaling cascades. In the present study, 23 NRs, including one EcR and two USPs, were identified in the genome of the predatory wolf spider Pardosa pseudoannulata. RNA interference(RNAi) targeting EcR and USP-1inhibited spiderling development and resulted in nonviable eggs in the egg sacs. EcR and USP-1responded to changes in ecdysteroid levels, and interference in ecdysteroid biosynthesis led to similar phenotypes as ds EcR and ds USP-1 treatments.These findings suggest that EcR/USP-1-mediated ecdysteroid signaling regulates P. pseudoannulata development and reproduction. The P.pseudoannulata females with suppressed ecdysteroid signaling proactively consumed their non-viable egg sacs, resulting in a 7.19 d shorter first reproductive cycle than the controls. Termination of the failed reproductive cycle enabled the spiders to produce a new egg sac more rapidly. This reproductive strategy may partially rescue the reduction in population growth due to non-viable eggs and compensate for the physiological expenditure of wasted maternal care, which would be beneficial for the conservation of P.pseudoannulata populations and their natural control of insect pests.
基金supported by the National Natural Science Foundation of China (32172390, 1672023 and 31741107)the Natural Science Foundation of Zhejiang Province, China (LZ20C140002)。
文摘The brown planthopper(Nilaparvata lugens) is the main migratory pest in many rice growing areas in Asia. E78 is a member of the nuclear hormone receptor superfamily which plays an important role in egg development and maternal regulation of early embryogenesis. In this study, brown planthopper E78(NlE78) was cloned, and the predicted amino acid sequence showed that it contains two conserved domains: NR-LBD and DBD. qRT-PCR showed that the expression of NlE78 is high in the fifth instar nymphs and the ovaries of females. After downregulation of NlE78, the rate of moulting failure(33.2%) increased significantly, and ovarian development was delayed. However, when NlE78was downregulated together with NlE93, the emergence rate increased significantly(78.79%), and ovarian development was similar to that when NlE78 was downregulated but not delayed. A co-immunoprecipitation experiment showed that NlE78 interacts with NlE93, a crucial downstream transcription factor of the ecdysone signalling pathway. Cellular localization by immunofluorescence revealed that NlE78 and NlE93 are expressed in the nucleus. This study indicates that NlE78 regulates ovarian development and moulting, possibly through its interaction with NlE93. This study is of great significance for the development of new pesticides and control methods based on newly discovered targets.
基金This research was supported by Grants from the Natural Science Foundation of China(31770688)the Fundamental Research Funds for the Central Universities(2572017AA17)+1 种基金the Ph.D.Programs Foundation of HeZe University(XY18BS06)the Ph.D.Programs Foundation of HeZe University(XY18BS05).
文摘Ecdysteroids play an important role in regulating diverse physiological processes in arthropods,such as molting,metamorphosis,reproduction and diapause.Ecdysteroids mediate the response by binding to a heterodimeric complex of two nuclear receptors:the ecdysone receptor and the ultraspiracle(USP).To investigate the role of USP in development of the Asian gypsy moth(Lymantria dispar),a USP cDNA was obtained from the transcriptome of L.dispar and verified by PCR.In-depth profiling of transcript levels of L.dispar USP-1(LdUSP-1)at different developmental stages and over time in thirdinstar larvae and different tissues isolated during the thirdinstar stage of L.dispar was then carried out.Transcript levels of LdUSP-1 were relatively high before 72 h in the third-instar larvae after ecdysis and in the adult male.The function of LdUSP-1 in molting was analyzed by knockdown of LdUSP-1 in third instar larvae using RNA interference.Silencing of LdUSP-1 significantly downregulated the transcript level of E75,an ecdysone-inducible gene,and of Sad,a Halloween gene.In addition,the duration of the third-instar stage was slightly shortened and larval mortality increased after the LdUSP-1 knockdown.
基金provided by the National Institutes of Health(R01AI033108,R01AI106892)awarded to MRS and MRBNational Science Foundation(IOS 1656236)awarded to MRS and MRB+3 种基金United States Department of Agriculture Hatch Project GEO00772 to MRSthe Pulliam Endowment(MRS)partially supported by the National Natural Science Foundation(31901876)the Natural Science Foundation of Jiangsu Province(KB20190900).
文摘Anautogenous mosquitoes must blood feed on a vertebrate host to produce eggs.Each gonadotrophic cycle is subdivided into a sugar-feeding previtellogenic phase that produces primary follicles and a blood meal-activated vitellogenic phase in which large numbers of eggs synchronously mature and are laid.Multiple endocrine factors including juvenile hormone(JH),insulin-like peptides(ILPs),ovary ecdysteroidogenic hormone(OEH),and 20-hydroxyecdysone(20E)coordinate each gonadotrophic cycle.Egg formation also requires nutrients from feeding that are stored in the fat body.Regulation of egg formation is best understood in Aedes aegypti but the role different endocrine factors play in regulating nutrient mobilization and storage remains unclear.In this study,we report that adult female Ae.aegypti maintained triacylglycerol(TAG)stores during the previtellogenic phase of the first gonadotrophic cycle while glycogen stores declined.In contrast,TAG and glycogen stores were rapidly mobilized during the vitellogenic phase and then replenishment.Several genes encoding enzymes with functions in TAG and glycogen metabolism were differentially expressed in the fat body,which suggested regulation was mediated in part at the transcriptional level.Gain of function assays indicated that stored nutrients were primarily mobilized by adipokinetic hormone(AKH)while juvenoids and OEH regulated replenishment.ILP3 further showed evidence of negatively regulating certain lipolytic enzymes.Loss of function assays indicated AKH depends on the AKH receptor(AKHR)for function.Altogether,our results indicate that the opposing activities of different hormones regulate nutrient stores during a gonadotrophic cycle in Ae.aegypti.
文摘The paradigm, still around in textbooks, that ＇in insects sex is strictly genetic, thus that they do not have sex hormones＇, is mainly based on a wrong interpretation of the ＇gynandromorph argument＇. It is no longer tenable. Given the fact that vertebrates and invertebrates probably had a common, sexually reproducing ancestor, there is no reason to assume that only vertebrates need sex hormones. The major function of sex hormones is to inform the somatoplasm about developmental changes that take place in the gonads. In contrast to juvenile hormone and neuropeptides, ecdysteroids meet all criteria to act as sex hormones, which was probably their ancient role. Their much better documented role in moulting and metamorphosis was a secondary acquisition that enabled arthropods to cope with growth problems, imposed by a rigid cuticle. Female insects use 20-hydroxyecdysone （20E）, secreted by the follicle cells of the ovary, in a similar way as females of egg-laying vertebrates use estrogens. For a variety of reasons, the possibility that ecdysteroids, in particular ecdysone （E）, might also act as sex hormones in male insects, thus as the counterpart of testosterone of vertebrates, has been very much overlooked. Thanks to the recent discovery of the molecular basis of the haploid-diploid system of sex determination in the honeybee, the characterization of Halloween genes, proteomics, RNAi and so on, it now becomes possible to verify whether in insects, as with vertebrates, males are the endocrinologically default gender form.
基金Acknowledgments The research was supported by the grants from National Natural Science Foundation of China （Grant No. 31172154） and the National Basic Research Program of China （973 Program, No. 2012CB114101）.
文摘Ecdysone receptor （EcR） and ultraspiracle （USP） form heterodimers to mediate ecdysteroid signaling during molting and metamorphosis. Various EcR/USP heterodimers have been reported. However, it is unclear what kind of EcR/USP combination is adopted by lepidopteran insects during the larval-pupal metamorphosis and whether the EcR/USP heterodimer varies among different tissues. To address these questions, two isoforms of each EcR and USP were cloned from the common cutworm, their messenger RNA expression patterns were examined by real-time quantitative polymerase chain reaction in different tissues during the larval-pupal metamorphosis and in the midgut in response to hormonal induction. Furthermore, their subcellular localization and protein-protein interaction were explored by transient expression and far-western blotting, respectively. All the four genes were significantly up-regulated in prepuae and/or pupae. The expression profiles of EcRB1 and USP1 were nearly identical to each other in the epidermis, fat body and midgut, and a similar situation also applied to EcRA and USP2. The three genes responded to 20-hydroxyecdysone （20E） induction except for USP2, and USP1 could be up-regulated by both 20E and juvenile hormone. The four proteins mainly localized in the nucleus and the nuclear localization was promoted by 20E. The protein-protein interaction between each EcR and USP was found in vitro. These results suggest that two types of EcR/USP heterodimer （EeRA/USP2 and EcRB 1/USP1） may exist simultaneously in the common cutworm, and the latter should play more important roles during the larval-pupal metamorphosis. In addition, the types of EcR/USP heterodimer do not vary in the tissues which undergo histolysis and regeneration during metamorphosis.
基金supported by the National Key R&D Program of China(2019YFD1002100)National Natural Science Foundation(31871969)the earmarked fund for Modern Agro-industry(Citrus)Technology Research System of China(CARS-26).
文摘Spider mites have one ecdysone receptor(EcR)and multiple retinoid X receptors(RXRs).However,the function of these RXRs in spider mite development is unknown.Here,we screened the expression dynamics of two PcRXR isoforms at 4 h intervals in the deutonymphal stage of Panonychus citri.The results showed that PcEcR had an expression pattern similar to that of PcRXR2.For PcRXR1,its expression remained at a certain high level,when there was a decrease of both PcEcR and PcRXR2.In situ hybridization showed that PcRXR2 was detected in the central nervous mass,while the ecdysteroid biosynthesis gene PcSpo was mainly expressed at the edge of the central nervous mass.RNAi-based silencing of PcRXR1 or PcRXR2 showed the same phenotype as in mites with that of silencing PcEcR.Furthermore,RNA-seq was used to mine the genes associated with the expression dynamics of PcRXR1 or PcRXR2,which revealed that the heterodimer of EcR-RXR2 in spider mites might be linked with the cell autophagy and tissue remodeling during apolysis,and RXR1 might be linked with new epicuticle and exocuticle secretion during ecdysis.Taken together,these results increase our understanding of the regulation mechanism of ecdysteroid signal pathway in spider mite development.
基金supported by grants from the National Science Foundation of China(31830093,32021001 and 31802005)Strategic Priority Research Program of Chinese Academy of Sciences(XDB11010600).
文摘U1 small nuclear ribonucleoproteins(U1 snRNP)associates with 5ʹsplice sites in the form of ribonucleoprotein particles and is highly conserved among species.The physiological functions of U1 snRNP in a lepidopteran model insect Bombyx mori is mostly unknown.Here,we showed that U1 snRNP plays an important role in the development of silkworm.Knockout of U1 snRNP in silkworm showed either delayed or stationary 1st instar larva development compared with the wild-type group.U1 snRNP deletion mutants exhibited abnormal cellular phenotypes with enlarged cell nucleus,scant cytoplasm and enlarged nuclei.RNA-seq analysis revealed that genes involved in metabolic pathway,biosynthesis of secondary metabolites and steroid hormone biosynthesis were significantly affected by U1 snRNP depletion.Taken together,our study suggests that U1 snRNP homeostasis plays an important role in silkworm development.
