To the Editor:Kinase cell division cycle 7(CDC7),a cell division cycle protein,takes a vital role in mediating DNA replication1.CDC7 complexes in the nucleus can phosphorylate the minichromosome maintenance complex(MC...To the Editor:Kinase cell division cycle 7(CDC7),a cell division cycle protein,takes a vital role in mediating DNA replication1.CDC7 complexes in the nucleus can phosphorylate the minichromosome maintenance complex(MCM)family members that bind to chromosomes.In addition,CDC7 kinase,as a molecular switch regulating DNA replication,can mediate DNA damage signaling pathways to stimulate cell cycle termination as well as DNA replication2.Studies have shown that CDC7 is overexpressed in many types of cancer cells,and its overexpression was related to poor patient survival,tumor grade,genetic instability,aneuploidy and so on3.Therefore,CDC7 is a promising target for antitumor therapy.展开更多
Asymmetric cell division(ACD) is a fundamental process that generates new cell types during development in eukaryotic species.In plant development,post-embryonic organogenesis driven by ACD is universal and more impor...Asymmetric cell division(ACD) is a fundamental process that generates new cell types during development in eukaryotic species.In plant development,post-embryonic organogenesis driven by ACD is universal and more important than in animals,in which organ pattern is preset during embryogenesis.Thus,plant development provides a powerful system to study molecular mechanisms underlying ACD.During the past decade,tremendous progress has been made in our understanding of the key components and mechanisms involved in this important process in plants.Here,we present an overview of how ACD is determined and regulated in multiple biological processes in plant development and compare their conservation and specificity among different model cell systems.We also summarize the molecular roles and mechanisms of the phytohormones in the regulation of plant ACD.Finally,we conclude with the overarching paradigms and principles that govern plant ACD and consider how new technologies can be exploited to fill the knowledge gaps and make new advances in the field.展开更多
Spatial periodic signal for cell differentiation in some multicellular organisms is generated according to Turing's principle for pattern formation.How a dividing cell responds to the signal of differentiation is ...Spatial periodic signal for cell differentiation in some multicellular organisms is generated according to Turing's principle for pattern formation.How a dividing cell responds to the signal of differentiation is addressed with the filamentous cyanobacterium Nostoc sp.PCC 7120,which forms the patterned distribution of heterocysts.We show that differentiation of a dividing cell was delayed until its division was completed and only one daughter cell became heterocyst.A mutant of patU3,which encodes an inhibitor of heterocyst formation,showed no such delay and formed heterocyst pairs from the daughter cells of cell division or dumbbell-shaped heterocysts from the cells undergoing cytokinesis.The patA mutant,which forms heterocysts only at the filament ends,restored intercalary heterocysts by a single nucleotide mutation of patU3,and double mutants of patU3/patA and patU3/hetF had the phenotypes of the patU3 mutant.We provide evidence that HetF,which can degrade PatU3,is recruited to cell divisome through its C-terminal domain.A HetF mutant with its N-terminal peptidase domain but lacking the C-terminal domain could not prevent the formation of heterocyst pairs,suggesting that the divisome recruitment of HetF is needed to sequester HetF for the delay of differentiation in dividing cells.Our study demonstrates that PatU3 plays a key role in celldivision coupled control of differentiation.展开更多
Salicylic acid(SA)plays a crucial role in plant immunity.However,its function in plant development is poorly understood.The quiescent center(QC),which maintains columella stem cells(CSCs)in the root apical meristem an...Salicylic acid(SA)plays a crucial role in plant immunity.However,its function in plant development is poorly understood.The quiescent center(QC),which maintains columella stem cells(CSCs)in the root apical meristem and typically exhibits low levels of cell division,is critical for root growth and development.Here,we show that the Arabidopsis thaliana SA overaccumulation mutant constitutively activated cell death 1(cad1),which exhibits increased cell division in the QC,is rescued by additional mutations in genes encoding the SA biosynthetic enzyme SALICYLIC ACID INDUCTION DEFFICIENT2(SID2)or the SA receptor NONEXPRESSER OF PR GENES1(NPR1),indicating that QC cell division in the cad1 mutant is promoted by the NPR1-dependent SA signaling pathway.The application of exogenous SA also promoted QC cell division in wild-type plants in a dose-dependent manner and largely suppressed the expression of genes involved in QC maintenance,including those encoding the APETALA2(AP2)transcription factors PLETHORA1(PLT1)and PLT2,as well as the homeodomain transcription factor WUSCHEL-RELATED HOMEOBOX5(WOX5).Moreover,we showed that SA promotes reactive oxygen species(ROS)production,which is necessary for the QC cell division phenotype in the cad1 mutant.These results provide insight into the function of SA in QC maintenance.展开更多
Objective Cell division cyclin 25 homolog C(Cdc25C)is a tumor-associated antigen candidate gene,and this may be used as an effective target in cancer treatment.The present study aims to evaluate the lysis effect of cy...Objective Cell division cyclin 25 homolog C(Cdc25C)is a tumor-associated antigen candidate gene,and this may be used as an effective target in cancer treatment.The present study aims to evaluate the lysis effect of cytotoxic T lymphocytes(CTLs)induced by dendritic cell line DC2.4 overexpressing Cdc25C,and the feasibility of Cdc25C as a component in hepatoma immunotherapy.Methods The mouse Cdc25C gene was ligated into a lentiviral vector,and transfected into DC2.4 cells.The DC2.4 cell phenotype and cytokine secretion were determined by flow cytometry and ELISA,respectively.CD8^(+)T cells were sorted from the spleens of C57BL/6 mice using a magnetic bead sorting kit obtained from Miltenyi Biotech,Germany,and co-cultured with DC2.4 cells for one week as effector cells.Then,IL-2,granzyme B and perforin were detected in the CTL culture medium by ELISA.Next,time-resolved fluorescence immunoassay was used to detect the immune killing effect of Cdc25C-specific CTLs on target cells.Meanwhile,the effect of blocking MHC-I sites on target cells with a monoclonal anti-MHC-I antibody was evaluated.Results The results revealed that Cdc25C could be stably overexpressed in DC2.4 cells by LV-Cdc25C infection.DC2.4 cells transfected with LV-Cdc25C secreted more IL-6,IL-12,TNF-αand IFN-γ,and had higher expression levels of CD40,CD86,CCR7 and MHC-II than unaltered DC2.4 cells.The elevated Cdc25C in dendritic cells also further increased the secretion of IL-2,granzyme B and perforin to elicit Cdc25C-specific CTLs,and induced the higher cytotoxicity in Hepa1-6 cell lines(P<0.05),but this had no effect on the target cells when MHC-I monoclonal antibodies were blocked.Conclusion DC2.4 cells transfected with LV-Cdc25C can induce specific CTLs,and result in a strong cellular immune response.The dendritic cells that overexpress Cdc25C may be useful for hepatoma immunotherapy.展开更多
Most bacteria assemble a ring-like macromolecular machinery scaffolded by the essential cytoskeletal protein FtsZ for cell division.Studies have broadly explored how FtsZ could polymerize at the correct place and time...Most bacteria assemble a ring-like macromolecular machinery scaffolded by the essential cytoskeletal protein FtsZ for cell division.Studies have broadly explored how FtsZ could polymerize at the correct place and time.Recently,the FtsZ-ring was found to exhibit dynamic treadmilling along the circumference of the division site,driven by GTP hydrolysis.This apparently directional motion of FtsZ seems to drive the movement of septal cell wall synthesis enzymes and to play an important role in modulating cell envelope constriction and septum morphogenesis.However,the relationship between FtsZ’s treadmilling dynamics and cell wall synthesis varies in different bacteria.More importantly,the biophysical and molecular mechanisms governing these dynamic processes are unclear.In this viewpoint,we will focus on some new and exciting studies surrounding this topic and discuss potential mechanisms that underlie how FtsZ’s treadmilling dynamics might regulate septal cell wall synthesis and cell division.展开更多
Analysis of cellular behavior is significant for studying cell cycle and detecting anti-cancer drugs. It is a very difficult task for image processing to isolate individual cells in confocal microscopic images of non-...Analysis of cellular behavior is significant for studying cell cycle and detecting anti-cancer drugs. It is a very difficult task for image processing to isolate individual cells in confocal microscopic images of non-stained live cell cultures. Because these images do not have adequate textural variations. Manual cell segmentation requires massive labor and is a time consuming process. This paper describes an automated cell segmentation method for localizing the cells of Chinese hamster ovary cell culture. Several kinds of high-dimensional feature descriptors, K-means clustering method and Chan-Vese model-based level set are used to extract the cellular regions. The region extracted are used to classify phases in cell cycle. The segmentation results were experimentally assessed. As a result, the proposed method proved to be significant for cell isolation. In the evaluation experiments, we constructed a database of Chinese Hamster Ovary Cell’s microscopic images which includes various photographing environments under the guidance of a biologist.展开更多
Grain size,characterized by a combination of grain length,width,and thickness,is one of the major determinants of yield in rice.The present study identified TATA-box binding protein-associated factor 2(TAF2)as an esse...Grain size,characterized by a combination of grain length,width,and thickness,is one of the major determinants of yield in rice.The present study identified TATA-box binding protein-associated factor 2(TAF2)as an essential component regulating transcription and determining grain size in rice.Map-based cloning showed that a G/T substitution in TAF2 resulted in a naturally occurring mutant called reduced grain size and plant height 1(rgh1).The mutants,with weak edited rgh1 alleles,exhibited a small grain phenotype with reduced grain length and width,while the severe knockout mutant(rgh1-2s)was dwarf and completely sterile.Allelic test performed between rgh1 and several edited alleles confirmed that the mutation in TAF2 caused the rgh1 phenotype.GUS staining showed that TAF2 was mainly expressed in the vascular bundles of roots,stems,leaves,and grains.The cytological analysis revealed that reduced cell division in the glumes resulted in the small grain phenotype of rgh1.Further RNA-sequencing detected altered expression of genes involved in the basic biological processes in rgh1 mutant.These findings provide novel insights into the TAF2-mediated genetic mechanism regulating grain size in rice.展开更多
Dwarfism is an important trait which is closely related to the efficiency of fruit orchard management and production.However,dwarfing cannot be widely applied in the cultivation of pears,especially Asian pears.Develop...Dwarfism is an important trait which is closely related to the efficiency of fruit orchard management and production.However,dwarfing cannot be widely applied in the cultivation of pears,especially Asian pears.Developing varieties with dwarf characteristics is a goal of paramount importance in pear breeding.In the present study,dwarf phenotype pears(DPPs)and arborescent phenotype pears(APPs)were obtained from the offspring of a cross between‘Aiyuxiang’and‘Cuiguan’pear cultivars,which exhibited dwarfed and arborescent statures,respectively.When compared with APPs,the heights of DPPs showed a 62.8%reduction,and the internode lengths were significantly shorter.Crossgrafting between DPPs and APPs demonstrated that the dwarfed phenotype of DPPs was primarily induced by the aerial portions of the plant,and independent of the root system.Observations of stem tissue sections showed that DPP cells were arranged chaotically with irregular shapes,and the average length was larger than that of the APP cells.A total of 1401 differently expressed genes(DEGs)in shoot apices between DPPs and APPs were identified by RNA-sequencing(RNA-Seq),and these DEGs were mainly enriched in the‘phytohormone-related pathways,cell wall metabolism and cell division’categories.Moreover,101 DEGs were identified as transcription factors(TFs).In DPPs,several brassinosteroids(BR)signaling and cell cycle-related genes were significantly down-regulated,while genes involved in BR and GA degradation were up-regulated.Comprehensive analysis of RNA-Seq data and stem tissue sections suggested that the dwarfed phenotype of DPPs could be primarily attributed to deficiencies in cell division.Previous work using simple sequence repeat(SSR)markers narrowed the location of the gene responsible for the dwarf phenotype of‘Le Nain Vert’.Through combined analysis of our transcriptomic data with the SSR results,we identified four genes as promising candidates for the dwarf phenotype,among which,a DELLA gene could be the most promising.The results presented in this study provide a sound foundation for further exploration into the genetic and molecular mechanisms underlying pear dwarfing.展开更多
CELL DIVISION CONTROL PROTEIN48(CDC48)is essential for membrane fusion,protein degradation,and other cellular processes.Here,we revealed the crucial role of CDC48B in regulating periclinal cell division in roots by an...CELL DIVISION CONTROL PROTEIN48(CDC48)is essential for membrane fusion,protein degradation,and other cellular processes.Here,we revealed the crucial role of CDC48B in regulating periclinal cell division in roots by analyzing the recessive gen1 mutant.We identified the GEN1 gene through map-based cloning and verified that GEN1 encodes CDC48B.gen1 showed severely inhibited root growth,increased periclinal cell division in the endodermis,defective middle cortex(MC)formation,and altered ground tissue patterning in roots.Consistent with these phenotypes,CYCLIND 6;1(CYCD6;1),a periclinal cell division marker,was upregulated in gen1 compared to Col-0.The ratio of SHR_(pro):SHR-GFP fluorescence in pre-dividing nuclei versus the adjacent stele decreased by 33%in gen1,indicating that the trafficking of SHORT-ROOT(SHR)decreased in gen1 when endodermal cells started to divide.These findings suggest that the loss of function of CDC48B inhibits the intercellular trafficking of SHR from the stele to the endodermis,thereby decreasing SHR accumulation in the endodermis.These findings shed light on the crucial role of CDC48B in regulating periclinal cell division in roots.展开更多
The mechanical force between cells and the extracellular microenvironment is crucial to many physiological processes such as cancer metastasis and stem cell differentiation. Mitosis plays an essential role in all thes...The mechanical force between cells and the extracellular microenvironment is crucial to many physiological processes such as cancer metastasis and stem cell differentiation. Mitosis plays an essential role in all these processes and thus an in-depth understanding of forces during mitosis gains insight into disease diagnosis and disease treatment. Here, we develop a traction force microscope method based on monolayer fluorescent beads for measuring the weak traction force (tens of Pa) of mitotic cells in three dimensions. We quantify traction forces of human ovarian granulosa (KGN) cells exerted on the extracellular matrix throughout the entire cell cycle in three dimensions. Our measurements reveal how forces vary during the cell cycle, especially during cell division. Furthermore, we study the effect of paclitaxel (PTX) and nocodazole (NDZ) on mitotic KGN cells through the measurement of traction forces. Our results show that mitotic cells with high concentrations of PTX exert a larger force than those with high concentrations of NDZ, which proved to be caused by changes in the structure and number of microtubules. These findings reveal the key functions of microtubule in generating traction forces during cell mitosis and explain how dividing cells regulate themselves in response to anti-mitosis drugs. This work provides a powerful tool for investigating cell-matrix interactions during mitosis and may offer a potential way to new therapies for cancer.展开更多
During the terminal stage of stomatal development,the R2 R3-MYB transcription factors FOUR LIPS(FLP/MYB124) and MYB88 limit guard mother cell division by repressing the transcript levels of multiple cell-cycle genes. ...During the terminal stage of stomatal development,the R2 R3-MYB transcription factors FOUR LIPS(FLP/MYB124) and MYB88 limit guard mother cell division by repressing the transcript levels of multiple cell-cycle genes. In Arabidopsis thaliana possessing the weak allele flp-1, an extra guard mother cell division results in two stomata having direct contact.Here, we identified an ethylmethane sulfonatemutagenized mutant, flp-1 xs01 c, which exhibited more severe defects than flp-1 alone, producing gianttumor-like cell clusters. XS01 C, encoding F-BOX STRESS-INDUCED 4(FBS4), is preferentially expressed in epidermal stomatal precursor cells.Overexpressing FBS4 rescued the defective stomatal phenotypes of flp-1 xs01 c and flp-1 mutants. The deletion or substitution of a conserved residue(Proline166) within the F-box domain of FBS4 abolished or reduced, respectively, its interaction with Arabidopsis Skp1-Like1(ASK1), the core subunit of the Skp1/Cullin/F-box E3 ubiquitin ligase complex. Furthermore, the FBS4 protein physically interacted with CYCA2;3 and induced its degradation through the ubiquitin-26 S proteasome pathway. Thus, in addition to the known transcriptional pathway, the terminal symmetric division in stomatal development is ensured at the post-translational level, such as through the ubiquitination of target proteins recognized by the stomatal lineage F-box protein FBS4.展开更多
Adaptation allows organisms to maintain a constant internal environment,which is optimised for growth.The unfolded protein response(UPR)is an example of a feedback loop that maintains endoplasmic reticulum(ER)homeosta...Adaptation allows organisms to maintain a constant internal environment,which is optimised for growth.The unfolded protein response(UPR)is an example of a feedback loop that maintains endoplasmic reticulum(ER)homeostasis,and is characteristic of how adaptation is often mediated by transcriptional networks.The more recent discovery of asymmetric division in maintaining ER homeostasis,however,is an example of how alternative non-transcriptional pathways can exist,but are overlooked by gold standard transcriptomic or proteomic population-based assays.In this study,we have used a combination of fluorescent reporters,flow cytometry and mathematical modelling to explore the relative roles of asymmetric cell division and the UPR in maintaining ER homeostasis.Under low ER stress,asymmetric division leaves daughter cells with an ER deficiency,necessitating activation of the UPR and prolonged cell cycle during which they can recover ER functionality before growth.Mathematical analysis of and simulation results from our mathematical model reinforce the experimental observations that low ER stress primarily impacts the growth rate of the daughter cells.These results demonstrate the interplay between homeostatic pathways and the importance of exploring sub-population dynamics to understand population adaptation to quantitatively different stresses.展开更多
Error-free cell division depends on the accurate assembly of the spindle midzone from dynamic spindle microtubules to ensure chromatid segregation during metaphase-anaphase transition.However,the mechanism underlying ...Error-free cell division depends on the accurate assembly of the spindle midzone from dynamic spindle microtubules to ensure chromatid segregation during metaphase-anaphase transition.However,the mechanism underlying the key transition from the mitotic spindle to central spindle before anaphase onset remains elusive.Given the prevalence of chromosome instability phenotype in gastric tumorigenesis,we developed a strategy to model context-dependent cell division using a combination of light sheet microscope and 3D gastric organoids.Light sheet microscopic image analyses of 3D organoids showed that CENP-E inhibited cells undergoing aberrant metaphase-anaphase transition and exhibiting chromosome segregation errors during mitosis.Highresolution real-time imaging analyses of 2D cell culture revealed that CENP-E inhibited cells undergoing central spindle splitting and chromosome instability phenotype.Using biotinylated syntelin as an affinity matrix,we found that CENP-E forms a complex with PRC1 in mitotic cells.Chemical inhibition of CENP-E in metaphase by syntelin prevented accurate central spindle assembly by perturbing temporal assembly of PRC1 to the midzone.Thus,CENP-E-mediated PRC1 assembly to the central spindle constitutes a temporal switch to organize dynamic kinetochore microtubules into stable midzone arrays.These findings reveal a previously uncharacterized role of CENP-E in temporal control of central spindle assembly.Since CENP-E is absent from yeast,we reasoned that metazoans evolved an elaborate central spindle organization machinery to ensure accurate sister chromatid segregation during anaphase and cytokinesis.展开更多
Cytoskeletal proteins are susceptible to glutathionylation under oxidizing conditions,and oxidative damage has been implicated in several neurodegenerative diseases.End-binding protein 1(EB1)is a master regulator of m...Cytoskeletal proteins are susceptible to glutathionylation under oxidizing conditions,and oxidative damage has been implicated in several neurodegenerative diseases.End-binding protein 1(EB1)is a master regulator of microtubule plus-end tracking proteins(+TIPs)and is critically involved in the control of microtubule dynamics and cellular processes.However,the impact of glutathionylation on EB1 functions remains unknown.Here we reveal that glutathionylation is important for controlling EB1 activity and protecting EB1 from irreversible oxidation.In vitro biochemical and cellular assays reveal that EB1 is glutathionylated.Diamide,a mild oxidizing reagent,reduces EB1 comet number and length in cells,indicating the impairment of microtubule dynamics.Three cysteine residues of EB1 are glutathionylated,with mutations of these three cysteines to serines attenuating microtubule dynamics but buffering diamide-induced decrease in microtubule dynamics.In addition,glutaredoxin 1(Grx1)deglutathionylates EB1,and Grx1 depletion suppresses microtubule dynamics and leads to defects in cell division orientation and cell migration,suggesting a critical role of Grx1-mediated deglutathionylation in maintaining EB1 activity.Collectively,these data reveal that EB1 glutathionylation is an important protective mechanism for the regulation of microtubule dynamics and microtubule-based cellular activities.展开更多
基金Zenji Research Laboratories for financial aid to this work
文摘To the Editor:Kinase cell division cycle 7(CDC7),a cell division cycle protein,takes a vital role in mediating DNA replication1.CDC7 complexes in the nucleus can phosphorylate the minichromosome maintenance complex(MCM)family members that bind to chromosomes.In addition,CDC7 kinase,as a molecular switch regulating DNA replication,can mediate DNA damage signaling pathways to stimulate cell cycle termination as well as DNA replication2.Studies have shown that CDC7 is overexpressed in many types of cancer cells,and its overexpression was related to poor patient survival,tumor grade,genetic instability,aneuploidy and so on3.Therefore,CDC7 is a promising target for antitumor therapy.
基金supported by grants from the National Natural Science Foundation of China (grant nos.32130010,31422008) to T.X.the National Institute of Health (grant no.GM131827)the National Science Foundation (grant nos.1851907,1952823,and 2049642) to J.D。
文摘Asymmetric cell division(ACD) is a fundamental process that generates new cell types during development in eukaryotic species.In plant development,post-embryonic organogenesis driven by ACD is universal and more important than in animals,in which organ pattern is preset during embryogenesis.Thus,plant development provides a powerful system to study molecular mechanisms underlying ACD.During the past decade,tremendous progress has been made in our understanding of the key components and mechanisms involved in this important process in plants.Here,we present an overview of how ACD is determined and regulated in multiple biological processes in plant development and compare their conservation and specificity among different model cell systems.We also summarize the molecular roles and mechanisms of the phytohormones in the regulation of plant ACD.Finally,we conclude with the overarching paradigms and principles that govern plant ACD and consider how new technologies can be exploited to fill the knowledge gaps and make new advances in the field.
基金supported by the National Natural Science Foundation of China (32070203)the National Key Research and Development Program of China (2017YFA0503703),National Key Research and Development Program of China (2019YFA0904700,2021YFA0910700,2021YFA0909700)Qidong-SLS Innovation Fund (202001539)。
文摘Spatial periodic signal for cell differentiation in some multicellular organisms is generated according to Turing's principle for pattern formation.How a dividing cell responds to the signal of differentiation is addressed with the filamentous cyanobacterium Nostoc sp.PCC 7120,which forms the patterned distribution of heterocysts.We show that differentiation of a dividing cell was delayed until its division was completed and only one daughter cell became heterocyst.A mutant of patU3,which encodes an inhibitor of heterocyst formation,showed no such delay and formed heterocyst pairs from the daughter cells of cell division or dumbbell-shaped heterocysts from the cells undergoing cytokinesis.The patA mutant,which forms heterocysts only at the filament ends,restored intercalary heterocysts by a single nucleotide mutation of patU3,and double mutants of patU3/patA and patU3/hetF had the phenotypes of the patU3 mutant.We provide evidence that HetF,which can degrade PatU3,is recruited to cell divisome through its C-terminal domain.A HetF mutant with its N-terminal peptidase domain but lacking the C-terminal domain could not prevent the formation of heterocyst pairs,suggesting that the divisome recruitment of HetF is needed to sequester HetF for the delay of differentiation in dividing cells.Our study demonstrates that PatU3 plays a key role in celldivision coupled control of differentiation.
基金supported by the National Natural Science Foundation of China Grant(31670187 and 31972388 to C.Y.)。
文摘Salicylic acid(SA)plays a crucial role in plant immunity.However,its function in plant development is poorly understood.The quiescent center(QC),which maintains columella stem cells(CSCs)in the root apical meristem and typically exhibits low levels of cell division,is critical for root growth and development.Here,we show that the Arabidopsis thaliana SA overaccumulation mutant constitutively activated cell death 1(cad1),which exhibits increased cell division in the QC,is rescued by additional mutations in genes encoding the SA biosynthetic enzyme SALICYLIC ACID INDUCTION DEFFICIENT2(SID2)or the SA receptor NONEXPRESSER OF PR GENES1(NPR1),indicating that QC cell division in the cad1 mutant is promoted by the NPR1-dependent SA signaling pathway.The application of exogenous SA also promoted QC cell division in wild-type plants in a dose-dependent manner and largely suppressed the expression of genes involved in QC maintenance,including those encoding the APETALA2(AP2)transcription factors PLETHORA1(PLT1)and PLT2,as well as the homeodomain transcription factor WUSCHEL-RELATED HOMEOBOX5(WOX5).Moreover,we showed that SA promotes reactive oxygen species(ROS)production,which is necessary for the QC cell division phenotype in the cad1 mutant.These results provide insight into the function of SA in QC maintenance.
基金the National Natural Science Foundation of China(No.81160264)the Natural Science Foundation of Guangxi Province(No.2016GXNSFAA380267 and No.2018GXNSFAA281071)+1 种基金the Guangxi First-class Discipline Project for Basic Medicine Sciences(No.GXFCDP-BMS-2018)the Research Enhancement Project for Junior Faculty in Higher Education Institutes of Guangxi(No.2018KY0419).
文摘Objective Cell division cyclin 25 homolog C(Cdc25C)is a tumor-associated antigen candidate gene,and this may be used as an effective target in cancer treatment.The present study aims to evaluate the lysis effect of cytotoxic T lymphocytes(CTLs)induced by dendritic cell line DC2.4 overexpressing Cdc25C,and the feasibility of Cdc25C as a component in hepatoma immunotherapy.Methods The mouse Cdc25C gene was ligated into a lentiviral vector,and transfected into DC2.4 cells.The DC2.4 cell phenotype and cytokine secretion were determined by flow cytometry and ELISA,respectively.CD8^(+)T cells were sorted from the spleens of C57BL/6 mice using a magnetic bead sorting kit obtained from Miltenyi Biotech,Germany,and co-cultured with DC2.4 cells for one week as effector cells.Then,IL-2,granzyme B and perforin were detected in the CTL culture medium by ELISA.Next,time-resolved fluorescence immunoassay was used to detect the immune killing effect of Cdc25C-specific CTLs on target cells.Meanwhile,the effect of blocking MHC-I sites on target cells with a monoclonal anti-MHC-I antibody was evaluated.Results The results revealed that Cdc25C could be stably overexpressed in DC2.4 cells by LV-Cdc25C infection.DC2.4 cells transfected with LV-Cdc25C secreted more IL-6,IL-12,TNF-αand IFN-γ,and had higher expression levels of CD40,CD86,CCR7 and MHC-II than unaltered DC2.4 cells.The elevated Cdc25C in dendritic cells also further increased the secretion of IL-2,granzyme B and perforin to elicit Cdc25C-specific CTLs,and induced the higher cytotoxicity in Hepa1-6 cell lines(P<0.05),but this had no effect on the target cells when MHC-I monoclonal antibodies were blocked.Conclusion DC2.4 cells transfected with LV-Cdc25C can induce specific CTLs,and result in a strong cellular immune response.The dendritic cells that overexpress Cdc25C may be useful for hepatoma immunotherapy.
基金This work is supported by the start-up funding by the University of Science and Technology of China KJ2070000083(X.Y)and KY9100000035(X.Y).
文摘Most bacteria assemble a ring-like macromolecular machinery scaffolded by the essential cytoskeletal protein FtsZ for cell division.Studies have broadly explored how FtsZ could polymerize at the correct place and time.Recently,the FtsZ-ring was found to exhibit dynamic treadmilling along the circumference of the division site,driven by GTP hydrolysis.This apparently directional motion of FtsZ seems to drive the movement of septal cell wall synthesis enzymes and to play an important role in modulating cell envelope constriction and septum morphogenesis.However,the relationship between FtsZ’s treadmilling dynamics and cell wall synthesis varies in different bacteria.More importantly,the biophysical and molecular mechanisms governing these dynamic processes are unclear.In this viewpoint,we will focus on some new and exciting studies surrounding this topic and discuss potential mechanisms that underlie how FtsZ’s treadmilling dynamics might regulate septal cell wall synthesis and cell division.
文摘Analysis of cellular behavior is significant for studying cell cycle and detecting anti-cancer drugs. It is a very difficult task for image processing to isolate individual cells in confocal microscopic images of non-stained live cell cultures. Because these images do not have adequate textural variations. Manual cell segmentation requires massive labor and is a time consuming process. This paper describes an automated cell segmentation method for localizing the cells of Chinese hamster ovary cell culture. Several kinds of high-dimensional feature descriptors, K-means clustering method and Chan-Vese model-based level set are used to extract the cellular regions. The region extracted are used to classify phases in cell cycle. The segmentation results were experimentally assessed. As a result, the proposed method proved to be significant for cell isolation. In the evaluation experiments, we constructed a database of Chinese Hamster Ovary Cell’s microscopic images which includes various photographing environments under the guidance of a biologist.
基金supported by the National Natural Science Foundation of China(31971918 and 32070348)the Chinese Academy of Sciences Innovation Project(XDA24010402).
文摘Grain size,characterized by a combination of grain length,width,and thickness,is one of the major determinants of yield in rice.The present study identified TATA-box binding protein-associated factor 2(TAF2)as an essential component regulating transcription and determining grain size in rice.Map-based cloning showed that a G/T substitution in TAF2 resulted in a naturally occurring mutant called reduced grain size and plant height 1(rgh1).The mutants,with weak edited rgh1 alleles,exhibited a small grain phenotype with reduced grain length and width,while the severe knockout mutant(rgh1-2s)was dwarf and completely sterile.Allelic test performed between rgh1 and several edited alleles confirmed that the mutation in TAF2 caused the rgh1 phenotype.GUS staining showed that TAF2 was mainly expressed in the vascular bundles of roots,stems,leaves,and grains.The cytological analysis revealed that reduced cell division in the glumes resulted in the small grain phenotype of rgh1.Further RNA-sequencing detected altered expression of genes involved in the basic biological processes in rgh1 mutant.These findings provide novel insights into the TAF2-mediated genetic mechanism regulating grain size in rice.
基金supported by the National Key Research and Development Program of China(2018YFD1000200)the Earmarked Fund for Jiangsu Agricultural Industry Technology System,China(JATS[2020]401)+3 种基金the National Science Foundation of China(31801835)the China Agriculture Research System of MOF and MARA(CARS-28)the Natural Science Foundation of Jiangsu Province,China(BK20180516)the Agricultural Variety Improvement Project of Shandong Province,China(2019LZGC008)。
文摘Dwarfism is an important trait which is closely related to the efficiency of fruit orchard management and production.However,dwarfing cannot be widely applied in the cultivation of pears,especially Asian pears.Developing varieties with dwarf characteristics is a goal of paramount importance in pear breeding.In the present study,dwarf phenotype pears(DPPs)and arborescent phenotype pears(APPs)were obtained from the offspring of a cross between‘Aiyuxiang’and‘Cuiguan’pear cultivars,which exhibited dwarfed and arborescent statures,respectively.When compared with APPs,the heights of DPPs showed a 62.8%reduction,and the internode lengths were significantly shorter.Crossgrafting between DPPs and APPs demonstrated that the dwarfed phenotype of DPPs was primarily induced by the aerial portions of the plant,and independent of the root system.Observations of stem tissue sections showed that DPP cells were arranged chaotically with irregular shapes,and the average length was larger than that of the APP cells.A total of 1401 differently expressed genes(DEGs)in shoot apices between DPPs and APPs were identified by RNA-sequencing(RNA-Seq),and these DEGs were mainly enriched in the‘phytohormone-related pathways,cell wall metabolism and cell division’categories.Moreover,101 DEGs were identified as transcription factors(TFs).In DPPs,several brassinosteroids(BR)signaling and cell cycle-related genes were significantly down-regulated,while genes involved in BR and GA degradation were up-regulated.Comprehensive analysis of RNA-Seq data and stem tissue sections suggested that the dwarfed phenotype of DPPs could be primarily attributed to deficiencies in cell division.Previous work using simple sequence repeat(SSR)markers narrowed the location of the gene responsible for the dwarf phenotype of‘Le Nain Vert’.Through combined analysis of our transcriptomic data with the SSR results,we identified four genes as promising candidates for the dwarf phenotype,among which,a DELLA gene could be the most promising.The results presented in this study provide a sound foundation for further exploration into the genetic and molecular mechanisms underlying pear dwarfing.
基金supported by the National Natural Science Foundation of China (31570291, 31570246)Funds of Shandong “Double Tops” Program (YL2017YSTD03)+3 种基金Shandong “Foreign Experts Double Hundred” Program (WST2017008)Shandong Key Basic Research (ZR2018ZC08N1)Natural Science Foundation of Heilongjiang Province (C2016002)the Fundamental Research Funds for the Central Universities (2572019CT03).
文摘CELL DIVISION CONTROL PROTEIN48(CDC48)is essential for membrane fusion,protein degradation,and other cellular processes.Here,we revealed the crucial role of CDC48B in regulating periclinal cell division in roots by analyzing the recessive gen1 mutant.We identified the GEN1 gene through map-based cloning and verified that GEN1 encodes CDC48B.gen1 showed severely inhibited root growth,increased periclinal cell division in the endodermis,defective middle cortex(MC)formation,and altered ground tissue patterning in roots.Consistent with these phenotypes,CYCLIND 6;1(CYCD6;1),a periclinal cell division marker,was upregulated in gen1 compared to Col-0.The ratio of SHR_(pro):SHR-GFP fluorescence in pre-dividing nuclei versus the adjacent stele decreased by 33%in gen1,indicating that the trafficking of SHORT-ROOT(SHR)decreased in gen1 when endodermal cells started to divide.These findings suggest that the loss of function of CDC48B inhibits the intercellular trafficking of SHR from the stele to the endodermis,thereby decreasing SHR accumulation in the endodermis.These findings shed light on the crucial role of CDC48B in regulating periclinal cell division in roots.
基金The authors gratefully acknowledge financial support from the National Natural Science Foundation of China(Nos.11872355,11627803,12072339,and 11872354)the Strategic Priority Research Program of the Chinese Academy of Science(No.XDB22040502).
文摘The mechanical force between cells and the extracellular microenvironment is crucial to many physiological processes such as cancer metastasis and stem cell differentiation. Mitosis plays an essential role in all these processes and thus an in-depth understanding of forces during mitosis gains insight into disease diagnosis and disease treatment. Here, we develop a traction force microscope method based on monolayer fluorescent beads for measuring the weak traction force (tens of Pa) of mitotic cells in three dimensions. We quantify traction forces of human ovarian granulosa (KGN) cells exerted on the extracellular matrix throughout the entire cell cycle in three dimensions. Our measurements reveal how forces vary during the cell cycle, especially during cell division. Furthermore, we study the effect of paclitaxel (PTX) and nocodazole (NDZ) on mitotic KGN cells through the measurement of traction forces. Our results show that mitotic cells with high concentrations of PTX exert a larger force than those with high concentrations of NDZ, which proved to be caused by changes in the structure and number of microtubules. These findings reveal the key functions of microtubule in generating traction forces during cell mitosis and explain how dividing cells regulate themselves in response to anti-mitosis drugs. This work provides a powerful tool for investigating cell-matrix interactions during mitosis and may offer a potential way to new therapies for cancer.
基金supported by grants from the National Natural Science Foundation of China to J.L.(31771515 and 31970804)K.Y.(31871377 and 32070723)。
文摘During the terminal stage of stomatal development,the R2 R3-MYB transcription factors FOUR LIPS(FLP/MYB124) and MYB88 limit guard mother cell division by repressing the transcript levels of multiple cell-cycle genes. In Arabidopsis thaliana possessing the weak allele flp-1, an extra guard mother cell division results in two stomata having direct contact.Here, we identified an ethylmethane sulfonatemutagenized mutant, flp-1 xs01 c, which exhibited more severe defects than flp-1 alone, producing gianttumor-like cell clusters. XS01 C, encoding F-BOX STRESS-INDUCED 4(FBS4), is preferentially expressed in epidermal stomatal precursor cells.Overexpressing FBS4 rescued the defective stomatal phenotypes of flp-1 xs01 c and flp-1 mutants. The deletion or substitution of a conserved residue(Proline166) within the F-box domain of FBS4 abolished or reduced, respectively, its interaction with Arabidopsis Skp1-Like1(ASK1), the core subunit of the Skp1/Cullin/F-box E3 ubiquitin ligase complex. Furthermore, the FBS4 protein physically interacted with CYCA2;3 and induced its degradation through the ubiquitin-26 S proteasome pathway. Thus, in addition to the known transcriptional pathway, the terminal symmetric division in stomatal development is ensured at the post-translational level, such as through the ubiquitination of target proteins recognized by the stomatal lineage F-box protein FBS4.
文摘Adaptation allows organisms to maintain a constant internal environment,which is optimised for growth.The unfolded protein response(UPR)is an example of a feedback loop that maintains endoplasmic reticulum(ER)homeostasis,and is characteristic of how adaptation is often mediated by transcriptional networks.The more recent discovery of asymmetric division in maintaining ER homeostasis,however,is an example of how alternative non-transcriptional pathways can exist,but are overlooked by gold standard transcriptomic or proteomic population-based assays.In this study,we have used a combination of fluorescent reporters,flow cytometry and mathematical modelling to explore the relative roles of asymmetric cell division and the UPR in maintaining ER homeostasis.Under low ER stress,asymmetric division leaves daughter cells with an ER deficiency,necessitating activation of the UPR and prolonged cell cycle during which they can recover ER functionality before growth.Mathematical analysis of and simulation results from our mathematical model reinforce the experimental observations that low ER stress primarily impacts the growth rate of the daughter cells.These results demonstrate the interplay between homeostatic pathways and the importance of exploring sub-population dynamics to understand population adaptation to quantitatively different stresses.
基金This work was supported in part by the National NaturalScience Foundation of China(31430054,31320103904,31621002,31671405,31601097,91854203,91753000,and91853115)'Strategic Priority Research Program'of the ChineseAcademy of Sciences(XDB19000000)+2 种基金the National Key Researchand Development Program of China(2017YFA0503600 and2016YFA-0100500)MOE Innovative Team project(IRT_17R102)and the US National Institutes of Health(CA164133,DK56292,and DK115812).
文摘Error-free cell division depends on the accurate assembly of the spindle midzone from dynamic spindle microtubules to ensure chromatid segregation during metaphase-anaphase transition.However,the mechanism underlying the key transition from the mitotic spindle to central spindle before anaphase onset remains elusive.Given the prevalence of chromosome instability phenotype in gastric tumorigenesis,we developed a strategy to model context-dependent cell division using a combination of light sheet microscope and 3D gastric organoids.Light sheet microscopic image analyses of 3D organoids showed that CENP-E inhibited cells undergoing aberrant metaphase-anaphase transition and exhibiting chromosome segregation errors during mitosis.Highresolution real-time imaging analyses of 2D cell culture revealed that CENP-E inhibited cells undergoing central spindle splitting and chromosome instability phenotype.Using biotinylated syntelin as an affinity matrix,we found that CENP-E forms a complex with PRC1 in mitotic cells.Chemical inhibition of CENP-E in metaphase by syntelin prevented accurate central spindle assembly by perturbing temporal assembly of PRC1 to the midzone.Thus,CENP-E-mediated PRC1 assembly to the central spindle constitutes a temporal switch to organize dynamic kinetochore microtubules into stable midzone arrays.These findings reveal a previously uncharacterized role of CENP-E in temporal control of central spindle assembly.Since CENP-E is absent from yeast,we reasoned that metazoans evolved an elaborate central spindle organization machinery to ensure accurate sister chromatid segregation during anaphase and cytokinesis.
基金supported by the National Natural Science Foundation of China(31701216,31771542,31900502)the Natural Science Foundation of Shandong Province(ZR2017MC008)。
文摘Cytoskeletal proteins are susceptible to glutathionylation under oxidizing conditions,and oxidative damage has been implicated in several neurodegenerative diseases.End-binding protein 1(EB1)is a master regulator of microtubule plus-end tracking proteins(+TIPs)and is critically involved in the control of microtubule dynamics and cellular processes.However,the impact of glutathionylation on EB1 functions remains unknown.Here we reveal that glutathionylation is important for controlling EB1 activity and protecting EB1 from irreversible oxidation.In vitro biochemical and cellular assays reveal that EB1 is glutathionylated.Diamide,a mild oxidizing reagent,reduces EB1 comet number and length in cells,indicating the impairment of microtubule dynamics.Three cysteine residues of EB1 are glutathionylated,with mutations of these three cysteines to serines attenuating microtubule dynamics but buffering diamide-induced decrease in microtubule dynamics.In addition,glutaredoxin 1(Grx1)deglutathionylates EB1,and Grx1 depletion suppresses microtubule dynamics and leads to defects in cell division orientation and cell migration,suggesting a critical role of Grx1-mediated deglutathionylation in maintaining EB1 activity.Collectively,these data reveal that EB1 glutathionylation is an important protective mechanism for the regulation of microtubule dynamics and microtubule-based cellular activities.
