Interspecific hybridization and allopolyploidization contribute to the improvement of many important crops. Recently, we successfully developed an amphidiploid from an interspecific cross between cucumber(Cucumis sati...Interspecific hybridization and allopolyploidization contribute to the improvement of many important crops. Recently, we successfully developed an amphidiploid from an interspecific cross between cucumber(Cucumis sativus, 2n = 2x = 14) and its relative C. hystrix(2n = 2x = 24) followed by chemical induction of chromosome doubling. The resulting allotetraploid plant was self-pollinated for three generations. The fertility and seed set of the amphidiploid plants were very low. In this study, we investigated the meiotic chromosome behavior in pollen mother cells with the aid of fluorescence in situ hybridization, aiming to identify the reasons for the low fertility and seed set in the amphidiploid plants. Homologous chromosome pairing appeared normal, but chromosome laggards were common, owing primarily to asynchronous meiosis of chromosomes from the two donor genomes. We suggest that asynchronous meiotic rhythm between the two parental genomes is the main reason for the low fertility and low seed set of the C. hystrix–cucumber amphidiploid plants.展开更多
Alternative splicing can generate multiple mRNAs that differ in their untranslated regions or coding sequences,and these differences might affect mRNA stability or result in different protein isoforms with diverse fun...Alternative splicing can generate multiple mRNAs that differ in their untranslated regions or coding sequences,and these differences might affect mRNA stability or result in different protein isoforms with diverse functions and/or localizations.In this study,we isolated a sterile mutant in rice with abnormal meiosis of microspore mother cells and megaspore mother cells that carried a point mutation in OsRAD1 gene.Cloning of OsRAD1 cDNAs revealed three transcript variants,named as OsRAD1.1,OsRAD1.2 and OsRAD1.3,respectively,which were derived from alternative splicing of the last intron.Proteins derived from the three transcripts were mostly identical except the difference in the very C-terminal domain.The three transcripts exhibited similar expression patterns in various tissues,but the expression level of OsRAD1.1 was the highest.Specific knockout of OsRAD1.1 led to sterility,while knockout of OsRAD1.2 and OsRAD1.3 together did not change the plant fertility.Overexpression of OsRAD1.2 and OsRAD1.3 cDNAs in OsRAD1.1-specific mutant did not complement the plant fertility.Yeast two-hybrid assay showed that OsRAD1.1,but not OsRAD1.2 and OsRAD1.3,interacted with the three other meiosis proteins OsHUS1,OsRAD9 and OsRAD17,suggesting that the C-terminal domain of OsRAD1.1 is critical for the protein function.展开更多
Meiosis is the process of producing haploid gametes through a series of complex chromosomal events and the coordinated action of various proteins.The mitochondrial protease complex(ClpXP),which consists of caseinolyti...Meiosis is the process of producing haploid gametes through a series of complex chromosomal events and the coordinated action of various proteins.The mitochondrial protease complex(ClpXP),which consists of caseinolytic mitochondrial matrix peptidase X(ClpX)and caseinolytic protease P(ClpP)and mediates the degradation of misfolded,damaged,and oxidized proteins,is essential for maintaining mitochondrial homeostasis.ClpXP has been implicated in meiosis regulation,but its precise role is currently unknown.In this study,we engineered an inducible male germ cell-specific knockout caseinolytic mitochondrial matrix peptidase X(Clpx^(cKO))mouse model to investigate the function of ClpX in meiosis.We found that disrupting Clpx in male mice induced germ cell apoptosis and led to an absence of sperm in the epididymis.Specifically,it caused asynapsis of homologous chromosomes and impaired meiotic recombination,resulting in meiotic arrest in the zygotene-to-pachytene transition phase.The loss of ClpX compromised the double-strand break(DSB)repair machinery by markedly reducing the recruitment of DNA repair protein RAD51 homolog 1(RAD51)to DSB sites.This dysfunction may be due to an insufficient supply of energy from the aberrant mitochondria in Clpx^(cKO) spermatocytes,as discerned by electron microscopy.Furthermore,ubiquitination signals on chromosomes and the expression of oxidative phosphorylation subunits were both significantly attenuated in Clpx^(cKO) spermatocytes.Taken together,we propose that ClpX is essential for maintaining mitochondrial protein homeostasis and ensuring homologous chromosome pairing,synapsis,and recombination in spermatocytes during meiotic prophase I.展开更多
Mitogen-activated protein kinase (MAPK) is a family of Ser/Thr protein kinases expressed widely in eu-karyotic cells. MAPK is activated by a cascade of protein kinase phosphorylation and plays pivotal roles in regulat...Mitogen-activated protein kinase (MAPK) is a family of Ser/Thr protein kinases expressed widely in eu-karyotic cells. MAPK is activated by a cascade of protein kinase phosphorylation and plays pivotal roles in regulating meiosis process in oocytes. As an important physical substrate of MAPK, p90rsk mediates numerous MAPK functions. MAPK was activated at G2/M transition during meiosis. Its activity reached the peak at M I stage and maintained at this level until the time before the pronuclear formation after fertilization. There is complex interplay between MAPK and MPF in the meiosis regulation. Furthermore, other intracel-lular signal transducers, such as cAMP, protein kinase C and protein phosphotase, ect., also regulated the activity of MAPK at different stages during meiosis in oocytes. In the present article, the roles of MAPK signaling pathway in oo-cyte meiosis are reviewed and discussed.展开更多
Polyploidization is a basic feature of plant evolution. Nearly all of the main food, cotton and oil crops are polyploid. When ploidy levels increase, yields double; this phenomenon suggested a new strategy of rice bre...Polyploidization is a basic feature of plant evolution. Nearly all of the main food, cotton and oil crops are polyploid. When ploidy levels increase, yields double; this phenomenon suggested a new strategy of rice breeding that utilizes wide crosses and polyploidization dual advantages to breed super rice. Because low seed set rates in polyploid rice usually makes it difficult to breed, the selection of Ph-liked gene lines was emphasized. After progenies of indica-japonica were identified and selected, two poly- ploid lines, PMeS-1 and PMeS-2 with Polyploid Meiosis Stability (PMeS) genes were bred. The proce- dure included seven steps: selecting parents, crossing or multiple crossing, back-crossing, doubling chromosomes, identifying the polyploid, and choosing plants with high seed set rates that can breed themselves into stable lines. The characteristics of PMeS were determined by observing meiotic be- haviors and by cross-identification of seed sets. PMeS-1 and PMeS-2, (japonica rice), have several characteristics different from other polyploid rice lines, including a higher rate of seed set (more than 65%, increasing to more than 70% in their F1 offspring); and stable meiotic behaviors (pairing with bi- valents and quarivalents nearly without over-quarivalent in prophase, nearly without lagging chromo- somes in metaphase and without micronuclei in anaphase and telophase). The latter was obviously different from control polyploid line Dure-4X, which displayed abnormal meiotic behaviors including a higher rate of multivalents, univalents and trivalents in prophase, lagging chromosomes in metaphase and micronuclei in anaphase and telophase. There were also three differences of the breeding method between PMeS lines and normal diploid lines: chromosomes doubling, polyploidism identifying and higher seed set testing. The selection of PMeS lines is the first step in polyploid rice breeding; their use will advance the progress of polyploid rice breeding, which will in turn offer a new way to breed super rice.展开更多
THERE are 42 chromosomes in common wheat (Triticum aestivum L). The extra microchro-mosomes were discovered in alloplasmic lines of common wheat with cytoplasms of Ae. muti-ca, Secale cereale, Elytrigia elongatum and ...THERE are 42 chromosomes in common wheat (Triticum aestivum L). The extra microchro-mosomes were discovered in alloplasmic lines of common wheat with cytoplasms of Ae. muti-ca, Secale cereale, Elytrigia elongatum and Agropyron glaucum. The microchromo-somes were discovered in amphiploid of Triticum aestivum-Secale cereale (DDRR) too.展开更多
Programmed DNA double-strand breaks(DSBs)are necessary for meiosis in mammals.A sufficient number of DSBs ensure the normal pairing/synapsis of homologous chromosomes.Abnormal DSB repair undermines meiosis,leading to ...Programmed DNA double-strand breaks(DSBs)are necessary for meiosis in mammals.A sufficient number of DSBs ensure the normal pairing/synapsis of homologous chromosomes.Abnormal DSB repair undermines meiosis,leading to sterility in mammals.The DSBs that initiate recombination are repaired as crossovers and noncrossovers,and crossovers are required for correct chromosome separation.Thus,the placement,timing,and frequency of crossover formation must be tightly controlled.Importantly,mutations in many genes related to the formation and repair of DSB result in infertility in humans.These mutations cause nonobstructive azoospermia in men,premature ovarian insufficiency and ovarian dysgenesis in women.Here,we have illustrated the formation and repair of DSB in mammals,summarized major factors influencing the formation of DSB and the theories of crossover regulation.展开更多
Germ cells make two major decisions when they move from an indeterminate state to their final stage of gamete production.One decision is sexual commitment for sperm or egg production,and the other is to maintain mitot...Germ cells make two major decisions when they move from an indeterminate state to their final stage of gamete production.One decision is sexual commitment for sperm or egg production,and the other is to maintain mitotic division or entry into meiosis.It is unclear whether the two decisions are made as a single event or separate events,because there has been no evidence for the presence of germ cell sex prior to meiosis.Here we report direct evidence in the fish rainbow trout that gonia have distinct sexuality.We show that dazl expression occurs in both male and female gonia but exhibits differential intracellular distribution.More strikingly,we show that boule is highly expressed in male gonia but absent in female gonia.Therefore,mitotic gonia possess sex,sperm/egg decision and mitosis/meiosis decision are two independent events,and sperm/egg decision precedes mitosis/meiosis decision in rainbow trout,making this organism a unique vertebrate model for mechanistic understanding of germ cell sex differentiation and relationship between the two decisions.展开更多
Meiotic recombination is essential for reciprocal exchange of genetic information between homologous chromosomes and their subsequent proper segregation in sexually reproducing organisms. MLH1 and MLH3 belong to meios...Meiotic recombination is essential for reciprocal exchange of genetic information between homologous chromosomes and their subsequent proper segregation in sexually reproducing organisms. MLH1 and MLH3 belong to meiosis-specific members of the Mut L-homolog family, which are required for normal level of crossovers(COs) in some eukaryotes. However, their functions in plants need to be further elucidated.Here, we report the identification of Os MLH1 and reveal its functions during meiosis in rice. Using CRISPRCas9 approach, two independent mutants, Osmlh1-1 and Osmlh1-2, are generated and exhibited significantly reduced male fertility. In Osmlh1-1, the clearance of PAIR2 is delayed and partial ZEP1 proteins are not loaded into the chromosomes, which might be due to the deficient in resolution of interlocks at late zygotene. Thus, Os MLH1 is required for the assembly of synapsis complex. In Osmlh1-1, CO number is dropped by ~53% and the distribution of residual COs is consistent with predicted Poisson distribution,indicating that Os MLH1 is essential for the formation of interference-sensitive COs(class I COs). Os MLH1 interacts with Os MLH3 through their C-terminal domains. Mutation in Os MLH3 also affects the pollen fertility. Thus, our experiments reveal that the conserved heterodimer Mut Lg(Os MLH1-Os MLH3) is essential for the formation of class I COs in rice.展开更多
Leucine-rich-repeat kinase 2 (LRRK2) belongs to the Roco GTPase family and is a large multidomain protein harboring both GTPase and kinase activities. LRRK2 plays indispensable roles in many processes, such as autopha...Leucine-rich-repeat kinase 2 (LRRK2) belongs to the Roco GTPase family and is a large multidomain protein harboring both GTPase and kinase activities. LRRK2 plays indispensable roles in many processes, such as autophagy and vesicle trafficking in mitosis. In this study, we showed the critical roles of LRRK2 in mammalian oocyte meiosis. LRRK2 is mainly accumulated at the meiotic spindle periphery during oocyte maturation. Depleting LRRK2 led to the polar body extrusion defects and also induced large polar bodies in mouse oocytes. Mass spectrometry analysis and co-immunoprecipitation results showed that LRRK2 was associated with several actin-regulating factors, such as Fascin and Rho-kinase (ROCK), and depletion of LRRK2 affected the expression of ROCK, phosphorylated cofilin, and Fascin. Further analysis showed that LRRK2 depletion did not affect spindle organization but caused the failure of spindle migration, which was largely due to the decrease of cytoplasmic actin filaments. Moreover, LRRK2 showed a similar localization pattern to mitochondria, and LRRK2 was associated with several mitochondria-related proteins. Indeed, mitochondrial distribution and function were both disrupted in LRRK2-depleted oocytes. In summary, our results indicated the critical roles of LRRK2 in actin assembly for spindle migration and mitochondrial function in mouse oocyte meiosis.展开更多
In order to study the effects of ubiquitin-proteasome pathway (UPP) on mouse oo- cyte meiosis and cleavage, oocytes undergoing maturation and parthenogenetic activation and 1-cell embryos were treated with lactacystin...In order to study the effects of ubiquitin-proteasome pathway (UPP) on mouse oo- cyte meiosis and cleavage, oocytes undergoing maturation and parthenogenetic activation and 1-cell embryos were treated with lactacystin, a specific inhibitor of proteasome. The results indi- cated that the rate of GVBD was not influenced by the treatment, but polar body extrusion, par- thenogenesis and first cleavage were inhibited. Immunofluorescent staining using anti β-tubulin antibody indicated that the continuous treatment of lactacystin from GV stage disorganized microtubules and spindle assembly. When metaphase stage oocytes were treated with the drug, the already formed spindle structure was not affected , but the oocytes were arrested at meta- phases. The 1-cell embryos were arrested at interphase or metaphase of first mitosis when they were incubated in the drug. Proteasome regulatory subunit PA700 was located in the spindle region, as indicated by immunofluorescence. These results suggest that UPP has effects on the process of oocyte meiosis and early cleavage in many aspects, including normal organization of spindle at prophase and segregation of chromosomes at anaphase for normal meiosis.展开更多
Male meiosis is a complex process whereby spermatocytes undergo cell division to form haploid cells.This review focuses on the role of retinoic acid(RA)in meiosis,as well as several processes regulated by RA before ce...Male meiosis is a complex process whereby spermatocytes undergo cell division to form haploid cells.This review focuses on the role of retinoic acid(RA)in meiosis,as well as several processes regulated by RA before cell entry into meiosis that are critical for proper meiotic entry and completion.Here,we discuss RA metabolism in the testis as well as the roles of stimulated by retinoic acid gene 8(STRA8)and MEIOSIN,which are responsive to RA and are critical for meiosis.We assert that transcriptional regulation in the spermatogonia is critical for successful meiosis.展开更多
Meiosis is a critical cell division program that produces haploid gametes for sexual reproduction.Abnormalities in meiosis are often causes of infertility and birth defects(e.g.,Down syndrome).Most organisms use a hig...Meiosis is a critical cell division program that produces haploid gametes for sexual reproduction.Abnormalities in meiosis are often causes of infertility and birth defects(e.g.,Down syndrome).Most organisms use a highly specialized zipper-like protein complex,the synaptonemal complex(SC),to guide and stabilize pairing of homologous chromosomes in meiosis.Although the SC is critical for meiosis in many eukaryotes,there are organisms that perform meiosis without a functional SC.However,such SC-less meiosis is poorly characterized.To understand the features of SC-less meiosis and its adaptive significance,the ciliated protozoan Tetrahymena was selected as a model.Meiosis research in Tetrahymena has revealed intriguing aspects of the regulatory programs utilized in its SC-less meiosis,yet additional efforts are needed for obtaining an in-depth comprehension of mechanisms that are associated with the absence of SC.Here,aiming at promoting a wider application of Tetrahymena for meiosis research,we introduce basic concepts and core techniques for studying meiosis in Tetrahymena and then suggest future directions for expanding the current Tetrahymena meiosis research toolbox.These methodologies could be adopted for dissecting meiosis in poorly characterized ciliates that might reveal novel features.Such data will hopefully provide insights into the function of the SC and the evolution of meiosis from a unique perspective.展开更多
Preliminary genetic studies in Trechaleidae spider family show high variation in sex chromosomes and high heterocigocity,suggesting high chromatin plasticity.The trechaleids Paratrechalea ornata,Trechalea bucculenta a...Preliminary genetic studies in Trechaleidae spider family show high variation in sex chromosomes and high heterocigocity,suggesting high chromatin plasticity.The trechaleids Paratrechalea ornata,Trechalea bucculenta and Trechaleoides biocellata are present in Uruguay.Males offering nuptial gifts during courtship have been reported in P.ornata and T.bucculenta but not in T.biocellata.Nuptial gifts are an inherited trait probably highly affected by environmental factors,which play an important role in gene expression.We hypothesize that this trait could be associated with tissue-specific genes existing in G-bands.We investigate the male meiosis in these 3 species,their sex chromosome system and the effects of G-banding on their chromosomes,and elucidate genetic differences among them.Meiotic stages of the 3 species were submitted to Giemsa-staining and G-banding treatments.We observed a haploid number of n=11 in P.ornata and n=13 in both T.bucculenta and T.biocellata.Males from the 3 species presented an X_(1)X_(2)0 sex chromosome system,which is suggested as ancestral in Araneae.In P.ornata and T.bucculenta,both sex chromosomes were together and aligned in parallel until the segregation during anaphase I.In contrast to these species,sex chromosomes of T.biocellata usually remained distant from each other until diakinesis when they were observed associated in parallel disposition.Interstitial G-bands were similar in P.ornata and T.bucculenta,and they both differed from those in T.biocellata.The special behavior of sex chromosomes in T.biocellata as well as the different G-banding pattern of this species suggests the existence of novel modifications in this species.展开更多
Meiosis is a specialized cell division for producing haploid gametes in sexually reproducing organisms.In this study,we have independently identified a novel meiosis protein male meiosis recombination regulator(MAMERR...Meiosis is a specialized cell division for producing haploid gametes in sexually reproducing organisms.In this study,we have independently identified a novel meiosis protein male meiosis recombination regulator(MAMERR)/4930432 K21 Rik and showed that it is indispensable for meiosis prophase I progression in male mice.Using super-resolution structured illumination microscopy,we found that MAMERR functions at the same double-strand breaks as the replication protein A and meiosis-specific with OB domains/spermatogenesis associated 22 complex.We generated a Mamerr-deficient mouse model by deleting exons 3 e6 and found that most of Mamerrà/àspermatocytes were arrested at pachynema and failed to progress to diplonema,although they exhibited almost intact synapsis and progression to the pachytene stage along with XY body formation.Further mechanistic studies revealed that the recruitment of DMC1/RAD51 and heat shock factor 2 ebinding protein in Mamerrà/àspermatocytes was only mildly impaired with a partial reduction in double-strand break repair,whereas a substantial reduction in ubiquitination on the autosomal axes and on the XY body appeared as a major phenotype in Mamerrà/àspermatocytes.We propose that MAMERR may participate in meiotic prophase I progression by regulating the ubiquitination of key meiotic proteins on autosomes and XY chromosomes,and in the absence of MAMERR,the repressed ubiquitination of key meiotic proteins leads to pachytene arrest and cell death.展开更多
With the rapid development of omics technologies during the last several decades,genomics,transcriptomics,and proteomics have been extensively used to characterize gene or protein functions in many organisms at the ce...With the rapid development of omics technologies during the last several decades,genomics,transcriptomics,and proteomics have been extensively used to characterize gene or protein functions in many organisms at the cell or tissue level.However,metabolomics has not been conducted in reproductive organs,with a focus on meiosis in plants.In this study,we adopted a nuclear magnetic resonance(NMR)-based metabolomics approach to reveal the metabolic profile of inflorescences from two Arabidopsis accessions,Columbia(Col)and Landsberg erecta(Ler),and several sterile mutants caused by meiosis defects.We identified 68 dominant metabolites in the samples.Col and Ler displayed distinct metabolite profiles.Interest-ingly,mutants with similar meiotic defects,such as Atrad51-3,Atrfc1-2,and Atpol2a-2,exhibited similar alterations in metabolites,including upregulation of energy metabolites and promotion of compounds related to maintenance of genomic stability,cytoplasmic homeostasis,and membrane integrity.The collective data reveal distinct changes in metabolites in Arabidopsis inflorescences between the Col and Ler wild type accessions.NMR-based metabolomics could be an effective tool for molecular phenotyping in studies of aspects of plant reproductive development such as meiosis.展开更多
Subject Code:C06 Under the support of the National Natural Science Foundation of China,the research group led by Prof.Zhang Liangran(张亮然)from Shandong University,collaborated mainly with the research group led by P...Subject Code:C06 Under the support of the National Natural Science Foundation of China,the research group led by Prof.Zhang Liangran(张亮然)from Shandong University,collaborated mainly with the research group led by Prof.Nancy Kleckner from Harvard University,has demonstrated that human female meiosis has展开更多
Background:Irreversible cryodamage caused by oocyte vitrification limited its wild application in female fertility preservation.Antioxidants were always used to antagonist the oxidative stress caused by vitrification....Background:Irreversible cryodamage caused by oocyte vitrification limited its wild application in female fertility preservation.Antioxidants were always used to antagonist the oxidative stress caused by vitrification.However,the comprehensive mechanism underlying the protective role of antioxidants has not been studied.Procyanidin B2(PCB2)is a potent natural antioxidant and its functions in response to vitrification are still unknown.In this study,the effects of PCB2 on vitrified-thawed oocytes and subsequent embryo development were explored,and the mechanisms underlying the protective role of PCB2 were systematically elucidated.Results:Vitrification induced a marked decline in oocyte quality,while PCB2 could improve oocyte viability and further development after parthenogenetic activation.A subsequent study indicated that PCB2 effectively attenuated vitrification-induced oxidative stress,rescued mitochondrial dysfunction,and improved cell viability.Moreover,PCB2 also acts as a cortical tension regulator apart from strong antioxidant properties.Increased cortical tension caused by PCB2 would maintain normal spindle morphology and promote migration,ensure correct meiosis progression and finally reduce the aneuploidy rate in vitrified oocytes.Further study reveals that ATP biosynthesis plays a crucial role in cortical tension regulation,and PCB2 effectively increased the cortical tension through the electron transfer chain pathway.Additionally,PCB2 would elevate the cortical tension in embryo cells at morula and blastocyst stages and further improve blastocyst quality.What's more,targeted metabolomics shows that PCB2 has a beneficial effect on blastocyst formation by mediating saccharides and amino acids metabolism.Conclusions:Antioxidant PCB2 exhibits multi-protective roles in response to vitrification stimuli through mitochondria-mediated cortical tension regulation.展开更多
Autopolyploidy and allopolyploidy may represent an evolutionary advantage and are more common in plants than assumed. However, less attention has been paid to autopolyploidy than to allopolyploidy,and its evolutionary...Autopolyploidy and allopolyploidy may represent an evolutionary advantage and are more common in plants than assumed. However, less attention has been paid to autopolyploidy than to allopolyploidy,and its evolutionary consequences are largely unclear, especially for plants with high ploidy levels. In this study, we developed oligonucleotide(oligo)-based chromosome painting probes to identify individual chromosomes in S. spontaneum. Using fluorescence in situ hybridization(FISH), we investigated chromosome behavior during pachytene, metaphase, anaphase, and telophase of meiosis I(MI) in autotetraploid,autooctoploid, and autodecaploid S. spontaneum clones. All autopolyploid clones showed stable diploidized chromosome behavior;so that homologous chromosomes formed almost exclusively bivalents during MI. Two copies of homologous chromosome 8 with similar sizes in the autotetraploid clone showed preferential pairing with each other with respect to the other copies. However, sequence variation analysis showed no apparent differences among homologs of chromosome 8 and all other chromosomes. We suggest that either the stable diploidized pairing or the preferential pairing between homologous copies of chromosome 8 in the studied autopolyploid sugarcane are accounted for by unknown mechanisms other than DNA sequence similarity. Our results reveal evolutionary consequences of stable meiotic behavior in autopolyploid plants.展开更多
The transcriptomes of three different parts of the fertile tetrasporophyte of Gracilariopsis lemaneiformis,including tip(T),middle(M),and subjacent(S)parts,with a gradual tetrasporangium maturity were analyzed and com...The transcriptomes of three different parts of the fertile tetrasporophyte of Gracilariopsis lemaneiformis,including tip(T),middle(M),and subjacent(S)parts,with a gradual tetrasporangium maturity were analyzed and compared to identify the genes involved in the process of tetrasporogenesis.The number of differentially expressed genes(DEGs)for the Gple-S versus Gple-T comparison was 10296,and the numbers of DEGs for the Gple-S versus Gple-M and Gple-T versus Gple-M comparisons were 7435 and 1337,respectively.Gene Ontology and Kyoto Encyclopedia of Genes and Genomes(KEGG)pathway enrichment analyses were performed,and the results showed the enrichment of 132 KEGG pathways(corrected P<0.05).A total of 58 DEGs related to meiosis were screened and blasted against 18 meiosis-related genes(dmc1,mlh1,mnd1,msh4,msh2,msh6,mre11,pds5,pms1,rad21,rad50,rad51,smc1,smc2,smc4,smc5,smc6,and spo11),including four meiosis-specific genes.The transcriptome comparison indicated that in the T part,the meiosis,ribosome,and RNA transport-related genes were mostly up-regulated compared with those in the other two groups.In the M part,the genes related to ribosomes and the endoplasmic reticulum were also up-regulated compared with those in the lower part.Finally,in the S part,the genes associated with photosynthesis were mostly up-regulated,which might be helpful to the recovery from spore formation and release.展开更多
基金supported by Agriculture and Food Research Initiative Competitive Grant 2013-67013-21105 from the U.S. Department of Agriculture National Institute of Food to YWthe National Natural Science Foundation of China to YH (No. 31271350)
文摘Interspecific hybridization and allopolyploidization contribute to the improvement of many important crops. Recently, we successfully developed an amphidiploid from an interspecific cross between cucumber(Cucumis sativus, 2n = 2x = 14) and its relative C. hystrix(2n = 2x = 24) followed by chemical induction of chromosome doubling. The resulting allotetraploid plant was self-pollinated for three generations. The fertility and seed set of the amphidiploid plants were very low. In this study, we investigated the meiotic chromosome behavior in pollen mother cells with the aid of fluorescence in situ hybridization, aiming to identify the reasons for the low fertility and seed set in the amphidiploid plants. Homologous chromosome pairing appeared normal, but chromosome laggards were common, owing primarily to asynchronous meiosis of chromosomes from the two donor genomes. We suggest that asynchronous meiotic rhythm between the two parental genomes is the main reason for the low fertility and low seed set of the C. hystrix–cucumber amphidiploid plants.
基金supported by grants from Natural Science Foundation of Guangdong Province(Grant Nos.B030308008,2017A030310500 and A03013104)National Key Research and Development Plan Program(Grant Nos.2016YFD0101801 and 2016YFD0100406)+2 种基金Shenzhen Commission on Innovation and Technology Programs(Grant No.JCYJ20160229204920363)Guangzhou Science and Technology Innovation Commission(Grant No.201804010034)National Natural Science Foundation of China(Grant No.31500254).
文摘Alternative splicing can generate multiple mRNAs that differ in their untranslated regions or coding sequences,and these differences might affect mRNA stability or result in different protein isoforms with diverse functions and/or localizations.In this study,we isolated a sterile mutant in rice with abnormal meiosis of microspore mother cells and megaspore mother cells that carried a point mutation in OsRAD1 gene.Cloning of OsRAD1 cDNAs revealed three transcript variants,named as OsRAD1.1,OsRAD1.2 and OsRAD1.3,respectively,which were derived from alternative splicing of the last intron.Proteins derived from the three transcripts were mostly identical except the difference in the very C-terminal domain.The three transcripts exhibited similar expression patterns in various tissues,but the expression level of OsRAD1.1 was the highest.Specific knockout of OsRAD1.1 led to sterility,while knockout of OsRAD1.2 and OsRAD1.3 together did not change the plant fertility.Overexpression of OsRAD1.2 and OsRAD1.3 cDNAs in OsRAD1.1-specific mutant did not complement the plant fertility.Yeast two-hybrid assay showed that OsRAD1.1,but not OsRAD1.2 and OsRAD1.3,interacted with the three other meiosis proteins OsHUS1,OsRAD9 and OsRAD17,suggesting that the C-terminal domain of OsRAD1.1 is critical for the protein function.
基金supported by the Shenzhen Science and Technology Program,China(No.KQTD20190929172749226).
文摘Meiosis is the process of producing haploid gametes through a series of complex chromosomal events and the coordinated action of various proteins.The mitochondrial protease complex(ClpXP),which consists of caseinolytic mitochondrial matrix peptidase X(ClpX)and caseinolytic protease P(ClpP)and mediates the degradation of misfolded,damaged,and oxidized proteins,is essential for maintaining mitochondrial homeostasis.ClpXP has been implicated in meiosis regulation,but its precise role is currently unknown.In this study,we engineered an inducible male germ cell-specific knockout caseinolytic mitochondrial matrix peptidase X(Clpx^(cKO))mouse model to investigate the function of ClpX in meiosis.We found that disrupting Clpx in male mice induced germ cell apoptosis and led to an absence of sperm in the epididymis.Specifically,it caused asynapsis of homologous chromosomes and impaired meiotic recombination,resulting in meiotic arrest in the zygotene-to-pachytene transition phase.The loss of ClpX compromised the double-strand break(DSB)repair machinery by markedly reducing the recruitment of DNA repair protein RAD51 homolog 1(RAD51)to DSB sites.This dysfunction may be due to an insufficient supply of energy from the aberrant mitochondria in Clpx^(cKO) spermatocytes,as discerned by electron microscopy.Furthermore,ubiquitination signals on chromosomes and the expression of oxidative phosphorylation subunits were both significantly attenuated in Clpx^(cKO) spermatocytes.Taken together,we propose that ClpX is essential for maintaining mitochondrial protein homeostasis and ensuring homologous chromosome pairing,synapsis,and recombination in spermatocytes during meiotic prophase I.
基金This work was supported by the Special Funds for Major State Basic Research ("973") Project of China (Grang No. Gl 999055902) the Knowledge Innovation Program of the Chinese Academy of Sciences (Grant No. KSCX2-SW-303).
文摘Mitogen-activated protein kinase (MAPK) is a family of Ser/Thr protein kinases expressed widely in eu-karyotic cells. MAPK is activated by a cascade of protein kinase phosphorylation and plays pivotal roles in regulating meiosis process in oocytes. As an important physical substrate of MAPK, p90rsk mediates numerous MAPK functions. MAPK was activated at G2/M transition during meiosis. Its activity reached the peak at M I stage and maintained at this level until the time before the pronuclear formation after fertilization. There is complex interplay between MAPK and MPF in the meiosis regulation. Furthermore, other intracel-lular signal transducers, such as cAMP, protein kinase C and protein phosphotase, ect., also regulated the activity of MAPK at different stages during meiosis in oocytes. In the present article, the roles of MAPK signaling pathway in oo-cyte meiosis are reviewed and discussed.
基金the National Natural Science Foundation of China (Grant Nos. 39970447, 30240090, 30471063 and 30650002)the High Technology Research and Development Program of China (Grant No. SZ-01-02-02)+1 种基金the Chenguang Youth Science and Technology Project of Wuhan City (Grant No. 20045006071-31)the Educational Commission of Hubei Province of China (Grant No. 2004D004)
文摘Polyploidization is a basic feature of plant evolution. Nearly all of the main food, cotton and oil crops are polyploid. When ploidy levels increase, yields double; this phenomenon suggested a new strategy of rice breeding that utilizes wide crosses and polyploidization dual advantages to breed super rice. Because low seed set rates in polyploid rice usually makes it difficult to breed, the selection of Ph-liked gene lines was emphasized. After progenies of indica-japonica were identified and selected, two poly- ploid lines, PMeS-1 and PMeS-2 with Polyploid Meiosis Stability (PMeS) genes were bred. The proce- dure included seven steps: selecting parents, crossing or multiple crossing, back-crossing, doubling chromosomes, identifying the polyploid, and choosing plants with high seed set rates that can breed themselves into stable lines. The characteristics of PMeS were determined by observing meiotic be- haviors and by cross-identification of seed sets. PMeS-1 and PMeS-2, (japonica rice), have several characteristics different from other polyploid rice lines, including a higher rate of seed set (more than 65%, increasing to more than 70% in their F1 offspring); and stable meiotic behaviors (pairing with bi- valents and quarivalents nearly without over-quarivalent in prophase, nearly without lagging chromo- somes in metaphase and without micronuclei in anaphase and telophase). The latter was obviously different from control polyploid line Dure-4X, which displayed abnormal meiotic behaviors including a higher rate of multivalents, univalents and trivalents in prophase, lagging chromosomes in metaphase and micronuclei in anaphase and telophase. There were also three differences of the breeding method between PMeS lines and normal diploid lines: chromosomes doubling, polyploidism identifying and higher seed set testing. The selection of PMeS lines is the first step in polyploid rice breeding; their use will advance the progress of polyploid rice breeding, which will in turn offer a new way to breed super rice.
文摘THERE are 42 chromosomes in common wheat (Triticum aestivum L). The extra microchro-mosomes were discovered in alloplasmic lines of common wheat with cytoplasms of Ae. muti-ca, Secale cereale, Elytrigia elongatum and Agropyron glaucum. The microchromo-somes were discovered in amphiploid of Triticum aestivum-Secale cereale (DDRR) too.
基金This work is supported by National Key Research&Development Program of China(No.2018YFC1003400)National Natural Science Foundation of China(No.31771588)the Strategic Collaborative Research Program of the Ferring Institute of Reproductive Medicine(No.FIRMC200509)to MCL.
文摘Programmed DNA double-strand breaks(DSBs)are necessary for meiosis in mammals.A sufficient number of DSBs ensure the normal pairing/synapsis of homologous chromosomes.Abnormal DSB repair undermines meiosis,leading to sterility in mammals.The DSBs that initiate recombination are repaired as crossovers and noncrossovers,and crossovers are required for correct chromosome separation.Thus,the placement,timing,and frequency of crossover formation must be tightly controlled.Importantly,mutations in many genes related to the formation and repair of DSB result in infertility in humans.These mutations cause nonobstructive azoospermia in men,premature ovarian insufficiency and ovarian dysgenesis in women.Here,we have illustrated the formation and repair of DSB in mammals,summarized major factors influencing the formation of DSB and the theories of crossover regulation.
基金the Biomedical Research Council of Singapore(R-08-1-21-19-585&SBIC-SSCC C-002-2007).
文摘Germ cells make two major decisions when they move from an indeterminate state to their final stage of gamete production.One decision is sexual commitment for sperm or egg production,and the other is to maintain mitotic division or entry into meiosis.It is unclear whether the two decisions are made as a single event or separate events,because there has been no evidence for the presence of germ cell sex prior to meiosis.Here we report direct evidence in the fish rainbow trout that gonia have distinct sexuality.We show that dazl expression occurs in both male and female gonia but exhibits differential intracellular distribution.More strikingly,we show that boule is highly expressed in male gonia but absent in female gonia.Therefore,mitotic gonia possess sex,sperm/egg decision and mitosis/meiosis decision are two independent events,and sperm/egg decision precedes mitosis/meiosis decision in rainbow trout,making this organism a unique vertebrate model for mechanistic understanding of germ cell sex differentiation and relationship between the two decisions.
基金supported by the National Natural Science Foundation of China(31630054,31425018,31821005)Program for Chinese Outstanding Talents in Agricultural Scientific Research。
文摘Meiotic recombination is essential for reciprocal exchange of genetic information between homologous chromosomes and their subsequent proper segregation in sexually reproducing organisms. MLH1 and MLH3 belong to meiosis-specific members of the Mut L-homolog family, which are required for normal level of crossovers(COs) in some eukaryotes. However, their functions in plants need to be further elucidated.Here, we report the identification of Os MLH1 and reveal its functions during meiosis in rice. Using CRISPRCas9 approach, two independent mutants, Osmlh1-1 and Osmlh1-2, are generated and exhibited significantly reduced male fertility. In Osmlh1-1, the clearance of PAIR2 is delayed and partial ZEP1 proteins are not loaded into the chromosomes, which might be due to the deficient in resolution of interlocks at late zygotene. Thus, Os MLH1 is required for the assembly of synapsis complex. In Osmlh1-1, CO number is dropped by ~53% and the distribution of residual COs is consistent with predicted Poisson distribution,indicating that Os MLH1 is essential for the formation of interference-sensitive COs(class I COs). Os MLH1 interacts with Os MLH3 through their C-terminal domains. Mutation in Os MLH3 also affects the pollen fertility. Thus, our experiments reveal that the conserved heterodimer Mut Lg(Os MLH1-Os MLH3) is essential for the formation of class I COs in rice.
基金Funding This work was supported by the National Key Research and Development Program of China(2021YFC2700100)the National Natural Science Foundation of China(32170857).
文摘Leucine-rich-repeat kinase 2 (LRRK2) belongs to the Roco GTPase family and is a large multidomain protein harboring both GTPase and kinase activities. LRRK2 plays indispensable roles in many processes, such as autophagy and vesicle trafficking in mitosis. In this study, we showed the critical roles of LRRK2 in mammalian oocyte meiosis. LRRK2 is mainly accumulated at the meiotic spindle periphery during oocyte maturation. Depleting LRRK2 led to the polar body extrusion defects and also induced large polar bodies in mouse oocytes. Mass spectrometry analysis and co-immunoprecipitation results showed that LRRK2 was associated with several actin-regulating factors, such as Fascin and Rho-kinase (ROCK), and depletion of LRRK2 affected the expression of ROCK, phosphorylated cofilin, and Fascin. Further analysis showed that LRRK2 depletion did not affect spindle organization but caused the failure of spindle migration, which was largely due to the decrease of cytoplasmic actin filaments. Moreover, LRRK2 showed a similar localization pattern to mitochondria, and LRRK2 was associated with several mitochondria-related proteins. Indeed, mitochondrial distribution and function were both disrupted in LRRK2-depleted oocytes. In summary, our results indicated the critical roles of LRRK2 in actin assembly for spindle migration and mitochondrial function in mouse oocyte meiosis.
基金This work was supported by the National Natu-ral Science Foundation of China(Grant No.30270661)Beijing Natural Science Foundation(5032004)the Special Funds for Major State Basic Research Project(973)of China(No.G1999053901).
文摘In order to study the effects of ubiquitin-proteasome pathway (UPP) on mouse oo- cyte meiosis and cleavage, oocytes undergoing maturation and parthenogenetic activation and 1-cell embryos were treated with lactacystin, a specific inhibitor of proteasome. The results indi- cated that the rate of GVBD was not influenced by the treatment, but polar body extrusion, par- thenogenesis and first cleavage were inhibited. Immunofluorescent staining using anti β-tubulin antibody indicated that the continuous treatment of lactacystin from GV stage disorganized microtubules and spindle assembly. When metaphase stage oocytes were treated with the drug, the already formed spindle structure was not affected , but the oocytes were arrested at meta- phases. The 1-cell embryos were arrested at interphase or metaphase of first mitosis when they were incubated in the drug. Proteasome regulatory subunit PA700 was located in the spindle region, as indicated by immunofluorescence. These results suggest that UPP has effects on the process of oocyte meiosis and early cleavage in many aspects, including normal organization of spindle at prophase and segregation of chromosomes at anaphase for normal meiosis.
基金This work is supported by the National Institutes of Health(R01 HD10808 awarded to MDG).
文摘Male meiosis is a complex process whereby spermatocytes undergo cell division to form haploid cells.This review focuses on the role of retinoic acid(RA)in meiosis,as well as several processes regulated by RA before cell entry into meiosis that are critical for proper meiotic entry and completion.Here,we discuss RA metabolism in the testis as well as the roles of stimulated by retinoic acid gene 8(STRA8)and MEIOSIN,which are responsive to RA and are critical for meiosis.We assert that transcriptional regulation in the spermatogonia is critical for successful meiosis.
基金Funds for the Central Universities(No.202241003,to Dr.Miao Tian)the Natural Science Foundation of Shandong Province(ZR2022JQ13,to Dr.Miao Tian)+1 种基金by the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement(No.101024333)Dr.Rachel Howard-Till is supported by NIH RO1GM127571.
文摘Meiosis is a critical cell division program that produces haploid gametes for sexual reproduction.Abnormalities in meiosis are often causes of infertility and birth defects(e.g.,Down syndrome).Most organisms use a highly specialized zipper-like protein complex,the synaptonemal complex(SC),to guide and stabilize pairing of homologous chromosomes in meiosis.Although the SC is critical for meiosis in many eukaryotes,there are organisms that perform meiosis without a functional SC.However,such SC-less meiosis is poorly characterized.To understand the features of SC-less meiosis and its adaptive significance,the ciliated protozoan Tetrahymena was selected as a model.Meiosis research in Tetrahymena has revealed intriguing aspects of the regulatory programs utilized in its SC-less meiosis,yet additional efforts are needed for obtaining an in-depth comprehension of mechanisms that are associated with the absence of SC.Here,aiming at promoting a wider application of Tetrahymena for meiosis research,we introduce basic concepts and core techniques for studying meiosis in Tetrahymena and then suggest future directions for expanding the current Tetrahymena meiosis research toolbox.These methodologies could be adopted for dissecting meiosis in poorly characterized ciliates that might reveal novel features.Such data will hopefully provide insights into the function of the SC and the evolution of meiosis from a unique perspective.
基金We thank Fernando Costa,Macarena Gonzalez,Anita Aisenberg,Soledad Ghione,Rodrigo Postiglioni and Carlos Toscano-Gadea for their help in the collection of spiders.We thank Nicolas Grasso and Wanda Iriarte for kindly helping with the techniques and software images.We also would like to thank Fernando Costa for the constructive discussions,Estefania Stanley and Ted Henderson for the English corrections and 3 anonymous referees for valuable comments on the manuscript.
文摘Preliminary genetic studies in Trechaleidae spider family show high variation in sex chromosomes and high heterocigocity,suggesting high chromatin plasticity.The trechaleids Paratrechalea ornata,Trechalea bucculenta and Trechaleoides biocellata are present in Uruguay.Males offering nuptial gifts during courtship have been reported in P.ornata and T.bucculenta but not in T.biocellata.Nuptial gifts are an inherited trait probably highly affected by environmental factors,which play an important role in gene expression.We hypothesize that this trait could be associated with tissue-specific genes existing in G-bands.We investigate the male meiosis in these 3 species,their sex chromosome system and the effects of G-banding on their chromosomes,and elucidate genetic differences among them.Meiotic stages of the 3 species were submitted to Giemsa-staining and G-banding treatments.We observed a haploid number of n=11 in P.ornata and n=13 in both T.bucculenta and T.biocellata.Males from the 3 species presented an X_(1)X_(2)0 sex chromosome system,which is suggested as ancestral in Araneae.In P.ornata and T.bucculenta,both sex chromosomes were together and aligned in parallel until the segregation during anaphase I.In contrast to these species,sex chromosomes of T.biocellata usually remained distant from each other until diakinesis when they were observed associated in parallel disposition.Interstitial G-bands were similar in P.ornata and T.bucculenta,and they both differed from those in T.biocellata.The special behavior of sex chromosomes in T.biocellata as well as the different G-banding pattern of this species suggests the existence of novel modifications in this species.
基金supported by grants from the Hong Kong Research Grant Council(17114920,K.L.and R.H.W.L.)the University of Hong Kong(K.L.)+3 种基金the Sanming Project of Medicine in Shenzhen,China(SZSM201612083,W.S.B.Y.)High Level-Hospital Program,Health Commission of Guangdong Province,China(HKUSZH201902018,K.L.)Shenzhen-Hong Kong Innovation Circle Type D(K.L.)a grant from the NIH/NIGMS(National Institute of General Medical Sciences)R35GM118052(P.J.W.)
文摘Meiosis is a specialized cell division for producing haploid gametes in sexually reproducing organisms.In this study,we have independently identified a novel meiosis protein male meiosis recombination regulator(MAMERR)/4930432 K21 Rik and showed that it is indispensable for meiosis prophase I progression in male mice.Using super-resolution structured illumination microscopy,we found that MAMERR functions at the same double-strand breaks as the replication protein A and meiosis-specific with OB domains/spermatogenesis associated 22 complex.We generated a Mamerr-deficient mouse model by deleting exons 3 e6 and found that most of Mamerrà/àspermatocytes were arrested at pachynema and failed to progress to diplonema,although they exhibited almost intact synapsis and progression to the pachytene stage along with XY body formation.Further mechanistic studies revealed that the recruitment of DMC1/RAD51 and heat shock factor 2 ebinding protein in Mamerrà/àspermatocytes was only mildly impaired with a partial reduction in double-strand break repair,whereas a substantial reduction in ubiquitination on the autosomal axes and on the XY body appeared as a major phenotype in Mamerrà/àspermatocytes.We propose that MAMERR may participate in meiotic prophase I progression by regulating the ubiquitination of key meiotic proteins on autosomes and XY chromosomes,and in the absence of MAMERR,the repressed ubiquitination of key meiotic proteins leads to pachytene arrest and cell death.
基金supported by grants from the National Science Foundation of China(31570314 and 31925005)by funds from the State Key Laboratory of Genetic Engineering at Fudan University.
文摘With the rapid development of omics technologies during the last several decades,genomics,transcriptomics,and proteomics have been extensively used to characterize gene or protein functions in many organisms at the cell or tissue level.However,metabolomics has not been conducted in reproductive organs,with a focus on meiosis in plants.In this study,we adopted a nuclear magnetic resonance(NMR)-based metabolomics approach to reveal the metabolic profile of inflorescences from two Arabidopsis accessions,Columbia(Col)and Landsberg erecta(Ler),and several sterile mutants caused by meiosis defects.We identified 68 dominant metabolites in the samples.Col and Ler displayed distinct metabolite profiles.Interest-ingly,mutants with similar meiotic defects,such as Atrad51-3,Atrfc1-2,and Atpol2a-2,exhibited similar alterations in metabolites,including upregulation of energy metabolites and promotion of compounds related to maintenance of genomic stability,cytoplasmic homeostasis,and membrane integrity.The collective data reveal distinct changes in metabolites in Arabidopsis inflorescences between the Col and Ler wild type accessions.NMR-based metabolomics could be an effective tool for molecular phenotyping in studies of aspects of plant reproductive development such as meiosis.
文摘Subject Code:C06 Under the support of the National Natural Science Foundation of China,the research group led by Prof.Zhang Liangran(张亮然)from Shandong University,collaborated mainly with the research group led by Prof.Nancy Kleckner from Harvard University,has demonstrated that human female meiosis has
基金National Key Research and Development Program Topics,Grant/Award Number:2021YFD1200402Chinese Universities Scientific Fund,Grant/Award Number:2021TC061+6 种基金Natural Science Foundation of Hebei province,Grant/Award Number:H2020206254Special Program for Training and Guiding Outstanding Young and Middle-aged Talents,Grant/Award Number:SKLSGIHP2021A01National Natural Science Foundation of China,Grant/Award Number:81901562&31372307Key research and development projects in Hebei province,Grant/Award Number:18226604DProgram of Young and Middle-aged Scientific and technological Innovation Leaders of the Xinjiang Production and Construction Corps,Grant/Award Number:2018CB025Xinghuo program of the First Hospital of Hebei Medical University,Grant/Award Number:XH202005The Central Guidance on Local Science and Technology Development Fund of Hebei Province,Grant/Award Number:226Z7713G。
文摘Background:Irreversible cryodamage caused by oocyte vitrification limited its wild application in female fertility preservation.Antioxidants were always used to antagonist the oxidative stress caused by vitrification.However,the comprehensive mechanism underlying the protective role of antioxidants has not been studied.Procyanidin B2(PCB2)is a potent natural antioxidant and its functions in response to vitrification are still unknown.In this study,the effects of PCB2 on vitrified-thawed oocytes and subsequent embryo development were explored,and the mechanisms underlying the protective role of PCB2 were systematically elucidated.Results:Vitrification induced a marked decline in oocyte quality,while PCB2 could improve oocyte viability and further development after parthenogenetic activation.A subsequent study indicated that PCB2 effectively attenuated vitrification-induced oxidative stress,rescued mitochondrial dysfunction,and improved cell viability.Moreover,PCB2 also acts as a cortical tension regulator apart from strong antioxidant properties.Increased cortical tension caused by PCB2 would maintain normal spindle morphology and promote migration,ensure correct meiosis progression and finally reduce the aneuploidy rate in vitrified oocytes.Further study reveals that ATP biosynthesis plays a crucial role in cortical tension regulation,and PCB2 effectively increased the cortical tension through the electron transfer chain pathway.Additionally,PCB2 would elevate the cortical tension in embryo cells at morula and blastocyst stages and further improve blastocyst quality.What's more,targeted metabolomics shows that PCB2 has a beneficial effect on blastocyst formation by mediating saccharides and amino acids metabolism.Conclusions:Antioxidant PCB2 exhibits multi-protective roles in response to vitrification stimuli through mitochondria-mediated cortical tension regulation.
基金funded by the Startup Foundation from Nantong University (03083074)partially supported by the National Natural Science Foundation of China (31771862)+1 种基金Special Funds for Technology Innovation of Fujian Agriculture and Forestry University(KFA20001A)the Research Program of Guangxi Key Laboratory for Sugarcane Biology (GXKLSCB-20190203)。
文摘Autopolyploidy and allopolyploidy may represent an evolutionary advantage and are more common in plants than assumed. However, less attention has been paid to autopolyploidy than to allopolyploidy,and its evolutionary consequences are largely unclear, especially for plants with high ploidy levels. In this study, we developed oligonucleotide(oligo)-based chromosome painting probes to identify individual chromosomes in S. spontaneum. Using fluorescence in situ hybridization(FISH), we investigated chromosome behavior during pachytene, metaphase, anaphase, and telophase of meiosis I(MI) in autotetraploid,autooctoploid, and autodecaploid S. spontaneum clones. All autopolyploid clones showed stable diploidized chromosome behavior;so that homologous chromosomes formed almost exclusively bivalents during MI. Two copies of homologous chromosome 8 with similar sizes in the autotetraploid clone showed preferential pairing with each other with respect to the other copies. However, sequence variation analysis showed no apparent differences among homologs of chromosome 8 and all other chromosomes. We suggest that either the stable diploidized pairing or the preferential pairing between homologous copies of chromosome 8 in the studied autopolyploid sugarcane are accounted for by unknown mechanisms other than DNA sequence similarity. Our results reveal evolutionary consequences of stable meiotic behavior in autopolyploid plants.
基金This research was supported by the Key Program of Science and Technology Innovation in Ningbo(No.2019B10009)the National Natural Science Foundation of China(No.41476111).
文摘The transcriptomes of three different parts of the fertile tetrasporophyte of Gracilariopsis lemaneiformis,including tip(T),middle(M),and subjacent(S)parts,with a gradual tetrasporangium maturity were analyzed and compared to identify the genes involved in the process of tetrasporogenesis.The number of differentially expressed genes(DEGs)for the Gple-S versus Gple-T comparison was 10296,and the numbers of DEGs for the Gple-S versus Gple-M and Gple-T versus Gple-M comparisons were 7435 and 1337,respectively.Gene Ontology and Kyoto Encyclopedia of Genes and Genomes(KEGG)pathway enrichment analyses were performed,and the results showed the enrichment of 132 KEGG pathways(corrected P<0.05).A total of 58 DEGs related to meiosis were screened and blasted against 18 meiosis-related genes(dmc1,mlh1,mnd1,msh4,msh2,msh6,mre11,pds5,pms1,rad21,rad50,rad51,smc1,smc2,smc4,smc5,smc6,and spo11),including four meiosis-specific genes.The transcriptome comparison indicated that in the T part,the meiosis,ribosome,and RNA transport-related genes were mostly up-regulated compared with those in the other two groups.In the M part,the genes related to ribosomes and the endoplasmic reticulum were also up-regulated compared with those in the lower part.Finally,in the S part,the genes associated with photosynthesis were mostly up-regulated,which might be helpful to the recovery from spore formation and release.
