BACKGROUND Centromere protein A(CENPA)exhibits an increased expression level in primary human rectal cancer tissues,but its role has not been investigated.AIM To clarify the specific role and mechanism of CENPA in rec...BACKGROUND Centromere protein A(CENPA)exhibits an increased expression level in primary human rectal cancer tissues,but its role has not been investigated.AIM To clarify the specific role and mechanism of CENPA in rectal cancer progression.METHODS CENPA protein expression in rectal cancer tissues and cell lines were detected.CENPA was overexpressed and knocked down in SW837 and SW480 cells,and proliferation,invasion,apoptosis and epithelial-mesenchymal transition(EMT)marker protein levels were examined.O6-methylguanine DNA methyltransferase(MGMT)promoter methylation was assessed with methylation-specific poly-merase chain reaction.Co-immunoprecipitation assay verified the interaction between MGMT and protein tyrosine phosphatase nonreceptor type 4(PTPN4).SW837 cells with CENPA knockdown were injected subcutaneously into mice,and tumor growth was examined.RESULTS CENPA was upregulated in rectal cancer tissues and cell lines.CENPA overex-pression promoted proliferation,invasion and EMT,and inhibited apoptosis in rectal cancer cells.Whereas CENPA knockdown showed the opposite results.Moreover,CENPA inhibited MGMT expression by promoting DNA methyltrans-ferase 1-mediated MGMT promoter methylation.MGMT knockdown abolished the CENPA knockdown-mediated inhibition of rectal cancer cell progression.MGMT increased PTPN4 protein stability by inhibiting PTPN4 ubiquitination degradation via competing with ubiquitin-conjugating enzyme E2O for interacting with PTPN4.PTPN4 knockdown abolished the inhibitory effects of MGMT overexpression on rectal cancer cell progression.Moreover,CENPA knockdown inhibited xenograft tumor growth in vivo.CONCLUSION CENPA knockdown inhibited rectal cancer cell growth and attenuated xenograft tumor growth through regulating the MGMT/PTPN4 axis.展开更多
A thermo-insensitive pale green leaf mutant （pgl2） was isolated from T-DNA inserted transgenic lines of rice （Oryza sativa L. subsp, japonica cv. Nipponbare）. Genetic analysis indicated that the phenotype was caus...A thermo-insensitive pale green leaf mutant （pgl2） was isolated from T-DNA inserted transgenic lines of rice （Oryza sativa L. subsp, japonica cv. Nipponbare）. Genetic analysis indicated that the phenotype was caused by a recessive mutation in a single nuclear-encoded gene. To map the PGL2gene, an F2 population was constructed by crossing the mutant with Longtefu （Oryza sativa L. subsp, indica）. The PGL2 locus was roughly linked to SSR marker RM331 on chromosome 8. To finely map the gene, 14 new InDel markers were developed around the marker, and PGL2 was further mapped to a 2.37 Mb centromeric region. Analysis on chlorophyll contents of leaves showed that there was no obvious difference between the mutant and the wild type in total chlorophyll （Chl） content, while the ratio of Chl a / Chl b in the mutant was only about 1, which was distinctly lower than that in the wild type, suggesting that the PGL2 gene was related to the conversion between Chl a and Chl b. Moreover, the method of primer design around the centromeric region was discussed, which would provide insight into fine mapping of the functional genes in plant centromeres.展开更多
Plant centromeres are generally composed of tandem arrays of simple repeats that form a complex chromosome locus where the kinetochore forms and microtubules attach during mitosis and meiosis. Each chromosome has one ...Plant centromeres are generally composed of tandem arrays of simple repeats that form a complex chromosome locus where the kinetochore forms and microtubules attach during mitosis and meiosis. Each chromosome has one centromere region, which is essential for accurate division of the genetic material. Recently, chromosomes containing two centromere regions （called dicentric chromosomes） have been found in maize and wheat. Interestingly, some dicentric chromosomes are stable because only one centromere is active and the other one is inactivated. Because such arrays maintain their typical structure for both active and inactive centromeres, the specification of centromere activity has an epigenetic component independent of the DNA sequence. Under some circumstances, the inactive centromeres may recover centromere function, which is called centromere reactivation. Recent studies have highlighted the important changes, such as DNA methylation and histone modification, that occur during centromere inactivation and reactivation.展开更多
Using indirect immunofluorescence (IIF), an anti-centromere protein CenpG-serum was verified. Western blot of the protein extracts of 31 samples of breast cancer tissues and their normal (not cancerous ) tissues a lit...Using indirect immunofluorescence (IIF), an anti-centromere protein CenpG-serum was verified. Western blot of the protein extracts of 31 samples of breast cancer tissues and their normal (not cancerous ) tissues a little far away from them in the same individuals showed that, in the majority of the tests (71%), centromere protein CenpG over expressed in breast cancer tissues. And moreover, a kind of protein component whose molecular weight is 43 kd, and which can be recognized by anti-CenpG serum was found in two of the cancer samples. The results suggested that CenpG (together whith it, there may be other relative components),which has been found and named recently, may be related to cancer,and its differential expressing is probably related to malignant cell proliferation.展开更多
The centromere is a defining region that mediates chromosome attachment to kinetochore microtubules and proper segregation of the sister chromatids. Intriguingly, satellite DNA and centromeric retrotransposon as major...The centromere is a defining region that mediates chromosome attachment to kinetochore microtubules and proper segregation of the sister chromatids. Intriguingly, satellite DNA and centromeric retrotransposon as major DNA constituents of centromere showed baffling diversification and species-specific. However, the key kinetochore proteins are conserved in both plants and animals, particularly the centromere-specific histone H3-1ike protein （CENH3） in all functional centromeres. Recent studies have highlighted the importance of epigenetic mechanisms in the establishment and maintenance of centromere identity. Here, we review the progress and compendium of research on plant centromere in the light of recent data.展开更多
The centromere is an essential chromosome site at which the kinetochore forms and loads proteins needed for faithful segregation during the cell cycle and meiosis（Houben et al., 1999;Cleveland et al.,2003;Ma et al.,2...The centromere is an essential chromosome site at which the kinetochore forms and loads proteins needed for faithful segregation during the cell cycle and meiosis（Houben et al., 1999;Cleveland et al.,2003;Ma et al.,2007;Birchler and Han,2009）.Centromere specific sequences such as tandem repeats or transposable elements evolve quickly both within and between the species but have conserved kinetochore proteins（Henikoff and Furuyama,2010）.展开更多
Objective To investigate the expression of centromere protein-C （CENP-C） in villus tissue of the first-trimester spontaneous abortion （SA） and the correlation study of CENP-C expression with chromosome segregation...Objective To investigate the expression of centromere protein-C （CENP-C） in villus tissue of the first-trimester spontaneous abortion （SA） and the correlation study of CENP-C expression with chromosome segregation. Methods Fluorescence in situ hybridization （FISH） and G-banded karyotype analysis were used to detect the numerical chromosome abnormality in 94 villus tissues of women with SA. The participants were separated into case group （n=30） and control group （n--30） according to the results with FISH. The qRT-PCR and Western blotting analysis were used to assess the expression level of CENP-C. Results Forty-eight （51.06%） cases had observed the numerical chromosome abnormality, including 30positive cases and the positive rate was 31.91%. The main types of variation included trisomy 16, 21, 22, X monosomy and triploid. The expression levels of CENP-C mRNA and protein in case group were statistically higher than that in control group （P〈0.05）. Conclusion Expression of CENP-C in the villus tissues of women might be related to SA induced by chromosomal aneuploid.展开更多
Recently the antichromosome antisera from several scleroderma patients have been found to recognize the pellicle of metaphase and anaphase chromosomes. In order to identify the pellicle components, we used these antic...Recently the antichromosome antisera from several scleroderma patients have been found to recognize the pellicle of metaphase and anaphase chromosomes. In order to identify the pellicle components, we used these antichromosome antisera to screen a human embryonic cDNA library. The sequences of the positive clones are identical to the cDNA gene sequence of CENP-C (centromere protein C), a human centromere autoantigen. This result suggusts that CENP-C is a component of the pellicle of human metaphase and anaphase chromosomes.展开更多
An awned rice（Oryza sativa） plant carrying a tiny extra chromosome was discovered among the progeny of a telotrisomic line 2nt4L. Fluorescence in situ hybridization（FISH） using chromosome specific BAC clones revea...An awned rice（Oryza sativa） plant carrying a tiny extra chromosome was discovered among the progeny of a telotrisomic line 2nt4L. Fluorescence in situ hybridization（FISH） using chromosome specific BAC clones revealed that this extra chromosome was a ring chromosome derived from part of the long arm of chromosome 4. So the aneuploidy plant was accordingly named as 2nt4L ring. We did not detect any Cent O FISH signals on the ring chromosome, and found only the centromeric probe Centromeric Retrotransposon of Rice（CRR） was co-localized with the centromere-specific histone CENH3 as revealed by sequential FISH after immunodetection. The extra ring chromosome exhibited a unique segregation pattern during meiosis, including no pairing between the ring chromosome and normal chromosome 4during prophase I and pre-separation of sister chromatids at anaphase I.展开更多
The Triticum-Aegilops complex groups demonstrated high cross-affinity with each other to overcome the barriers of distant hybridization(Loureiro et al.,2023).Distant hybridization involves two distinct yet closely rel...The Triticum-Aegilops complex groups demonstrated high cross-affinity with each other to overcome the barriers of distant hybridization(Loureiro et al.,2023).Distant hybridization involves two distinct yet closely related events:hybridization and genome doubling.Previous studies have indicated that bursts of transposable elements(TEs)can occur as a consequence or concomitant to hybridization or genome duplication(Parisod et al.,2010).This raises an important scientific question regarding how the TEs-rich centromere region copes with genomic shock(McClintock,1984).The Triticum-Aegilops species complexes,particularly in the F1,So,and subsequent early generations resulting from successive selfcrossing,offer an opportunity to investigate whether the centromere environment undergoes reconstruction and the associated mechanisms that maintain genomic stability.展开更多
The aneuploid with isochromosome or telochromosome is ideal material for exploring the position of centromere in lingkage map. FOr obtaining these aneuploids in rice, the primary trisomics from triplo-1 to triplo-12 a...The aneuploid with isochromosome or telochromosome is ideal material for exploring the position of centromere in lingkage map. FOr obtaining these aneuploids in rice, the primary trisomics from triplo-1 to triplo-12 and the aneuploids derived from a triploid of indica rice variety Zhongxian 3037 were carefully investigated. From the offsprings of triplo-10, a primary trisomic of chromosome 10 of the variety, an isotetrasomic "triplo-10-1" was obtained. Cytological investigation revealed that a pair of extra isochromosomes of triplo-10-1 were come from the short arm of chromosome 10. In the offsprings of the isotetrasomic, a secondary trisomic "triplo-10-2" 5 in which the extra- chromosome was an isochromosome derived from the short arm of chromosome 10, was identified. With the isotetrasomic, secondary trisomic, primary trisomic and diploid of variety Zhongxian 3037, different molecular markers were used for exploring the position of the centromere of chromosome 10. Based on the DNA dosage effect, it was verified that the molecular markers G1125, G333 and L169 were located on the short arm, G1084 and other 16 available molecular markers were on the long arm of chromosome 10. So the centromere of chromosome 10 was located somewhere betweenG1125 and G1084 according to the RFLP linkage map given by Kurata et al[1]. The distance from G1125 to G1084 was about 3.2cM.展开更多
The centromere of eukaryotic chromosomes is the crucial locus responsible for sister chromatid cohesion and for correct segregation of chromosomes to daughter cells during cell division. In the structural genomics era...The centromere of eukaryotic chromosomes is the crucial locus responsible for sister chromatid cohesion and for correct segregation of chromosomes to daughter cells during cell division. In the structural genomics era, centromeres represent the last frontiers of higher eukaryotic genomes because of their densely methylated, highly repetitive and, heterochromatic DNA （Hall et al., 2004）. Although these functions are conserved among all eukaryotes, centromeric DNA sequences are evolving rapidly （Jiang et al., 2003）.展开更多
Polyploidization is recognized as a powerful driver of plant evolution and domestication.In the genus Gossypium,the natural hybridization of an A-genome ancestor and a D-genome ancestor gave rise to allopolyploid cott...Polyploidization is recognized as a powerful driver of plant evolution and domestication.In the genus Gossypium,the natural hybridization of an A-genome ancestor and a D-genome ancestor gave rise to allopolyploid cottons(Huang et al.,2024),such as Gossypium hirsutum and Gossypium barbadense.Previous cotton reference genomes(Du et al.,2018;Hu et al.,2019;Huang et al.,2020;Li et al.,2015;Wang et al.,2019;Yang et al.,2019;Zhang et al.,2015),although instrumental to cotton genetics and breeding,contained large assembly gaps,especially repetitive regions like centromeres.展开更多
Dear Editor,Spinach(Spinacia oleracea L.)is a diploid plant with n=6 chromosomes(2n=12)and is one of the world’s most important green leafy vegetables.The genus Spinacia is well suited for studying sex chromosome evo...Dear Editor,Spinach(Spinacia oleracea L.)is a diploid plant with n=6 chromosomes(2n=12)and is one of the world’s most important green leafy vegetables.The genus Spinacia is well suited for studying sex chromosome evolution because it is dioecious,has an XY sex determination system,and includes two wild species(She et al.,2023).The first chromosome-level spinach genome,assembled using next-generation sequencing reads in 2017,had only 47%of the sequence anchored to the chromosomes(Xu et al.,2017).展开更多
Dear Editor,Legumes,including soybean and alfalfa,are vital agricultural crops worldwide,providing high-quality protein and oil sources for humans and animals.In addition,legumes also provide nitrogen for soil improve...Dear Editor,Legumes,including soybean and alfalfa,are vital agricultural crops worldwide,providing high-quality protein and oil sources for humans and animals.In addition,legumes also provide nitrogen for soil improvement,benefiting from their symbiotic associations with nitrogen-fixing bacteria.展开更多
R-loops play various roles in many physiological processes,however,their role in meiotic division remains largely unknown.Here we show that R-loops and their regulator RNase H1 are present at centromeres during oocyte...R-loops play various roles in many physiological processes,however,their role in meiotic division remains largely unknown.Here we show that R-loops and their regulator RNase H1 are present at centromeres during oocyte meiotic divisions.Proper centromeric R-loops are essential to ensure chromosome alignment in oocytes during metaphase I(MI).Remarkably,both Rnaseh1 knockout and overexpression in oocytes lead to severe spindle assembly defects and chromosome misalignment due to dysregulation of R-loops at centromeres.Furthermore,we find that replication protein A(RPA)is recruited to centromeric R-loops,facilitating the deposition of ataxia telangiectasia-mutated and Rad3-related(ATR)kinase at centromeres by interacting with the ATR-interaction protein(ATRIP).The ATR kinase deposition triggers the activity of CHK1,stimulating the phosphorylation of Aurora B to finally promote proper spindle assembly and chromosome alignment at the equatorial plate.Most importantly,the application of ATR,CHK1,and Aurora B inhibitors could efficiently rescue the defects in spindle assembly and chromosome alignment due to RNase H1 deficiency in oocytes.Overall,our findings uncover a critical role of R-loops during mouse oocyte meiotic divisions,suggesting that dysregulation of R-loops may be associated with female infertility.Additionally,ATR,CHK1,and Aurora B inhibitors may potentially be used to treat some infertile patients.展开更多
The centromere is a highly organized structure mainly composed of repeat sequences,which make this region extremely difficult for sequencing and other analyses.It plays a conserved role in equal division of chromosome...The centromere is a highly organized structure mainly composed of repeat sequences,which make this region extremely difficult for sequencing and other analyses.It plays a conserved role in equal division of chromosomes into daughter cells in both mitosis and meiosis.However,centromere sequences show notable plasticity.In a dicentric chromosome,one of the centromeres can become inactivated with the underlying DNA unchanged.Furthermore,formerly inactive centromeres can regain activity under certain conditions.In addition,neocentromeres without centromeric repeats have been found in a wide spectrum of species.This evidence indicates that epigenetic mechanisms together with centromeric sequences are associated with centromere specification.展开更多
During cell division,the accurate capture of sister kinetochores that are built on the centromeres of chromosomes by microtubules emanating from opposite spindle poles governs faithful chromosome segregation.To ensure...During cell division,the accurate capture of sister kinetochores that are built on the centromeres of chromosomes by microtubules emanating from opposite spindle poles governs faithful chromosome segregation.To ensure sister chromatids separate correctly,sister centromeres undergo resolution to achieve bipolar orientation prior to microtubule attachments.Failure of centromere resolution increases the frequency of merotelic attachments,with microtubules from opposite poles attaching to the same sister kinetochore,causing lagging chromosome,aneuploidy,and even cancer progression.The Aurora B-mediated tension-sensing machinery to correct erroneous kinetochore-microtubule attachments has been well studied.However,preventative mechanisms to avoid merotelic attachments that occurin the earlier mitotic stage are poorly understood.In this study,we found that inactivation of mitotickinase Aurora B/AIR-2 increases merotelic attachments in Caenorhabditis elegans.On one hand,Aurora B/AIR-2-deficient cells exhibit a delay in the occurrence of centromere resolution and a disruption in targeting condensin Il components to chromatin.On the other hand,loss of Aurora B/AIR-2 results in an increased localization of centromeric proteins CENP-A/HCP-3 and M18BP1/KNL-2 as well as the kinetochore protein MiS-12 on chromatin,which may generate ectopic kinetochores causing erroneous attachments.To conclude,this study elucidated that Aurora B/AIR-2 regulates sister centromere resolution and CENP-A/HCP-3 deposition to actively prevent merotely and chromosome instability in cells.展开更多
Rice(Oryza sativa),a major staple throughout the world and a model system for plant genomics and breeding,was the first crop genome sequenced almost two decades ago.However,reference genomes for all higher organisms t...Rice(Oryza sativa),a major staple throughout the world and a model system for plant genomics and breeding,was the first crop genome sequenced almost two decades ago.However,reference genomes for all higher organisms to date contain gaps and missing sequences.Here,we report the assembly and analysis of gap-free reference genome sequences for two elite O.sativa xian/indica rice varieties,Zhenshan 97 and Minghui 63,which are being used as a model system for studying heterosis and yield.Gap-free reference genomes provide the opportunity for a global view of the structure and function of centromeres.We show that all rice centromeric regions share conserved centromere-specific satellite motifs with different copy numbers and structures.In addition,the similarity of CentO repeats in the same chromosome is higher than across chromosomes,supporting a model of local expansion and homogenization.Both genomes have over 395 non-TE genes located in centromere regions,of which∼41%are actively transcribed.Two large structural variants at the end of chromosome 11 affect the copy number of resistance genes between the two genomes.The availability of the two gap-free genomes lays a solid foundation for further understanding genome structure and function in plants and breeding climate-resilient varieties.展开更多
Although the centromeres of some plants have been investlgated prevlously, our knowledge of the wheat centromere Is still very llmlted. To understand the structure and functlon of the wheat centromere, we used two cen...Although the centromeres of some plants have been investlgated prevlously, our knowledge of the wheat centromere Is still very llmlted. To understand the structure and functlon of the wheat centromere, we used two centromeric repeats （RCS1 and CCS1-5ab） to obtain some centromere-assoclated bacterial artificial chromosome （BAC） clones in 32 RCS1-related BAC clones that had been screened out from a diploid wheat （Triticum boeoticum Boiss.; 2n=2x=14） BAC library. Southern hybridization results indicated that, of the 32 candidates, there were 28 RCS1-positive clones. Based on gel blot patterns, the frequency of RCS1 was approximately one copy every 69.4 kb in these 28 RCS1-positive BAC clones. More bands were detected when the same filter was probed with CCS1-5ab. Furthermore, the CCS1 bands covered all the bands detected by RCS1, which suggests that some CCS1 repeats were distributed together with RCS1. The frequency of CCS1 families was once every 35.8 kb, nearly twice that of RCS1. Fluorescence in situ hybridization （FISH） analysis Indicated that the five BAC clones containing RCS1 and CCS1 sequences all detected signals at the centromerlc regions in hexaplold wheat, but the signal intensities on the A-genome chromosomes were stronger than those on the B- and/or Dgenome chromosomes. The FISH analysis among nine Triticeae cereals indicated that there were A-genomespecific （or rich） sequences dispersing on chromosome arms in the BAC clone TbBACS. In addition, at the interphase cells, the centromeres of diploid species usually clustered at one pole and formed a ring-like allocation In the period before metaphase.展开更多
基金This study was reviewed and approved by the Ethic Committee of Medical College of Henan Vocational University of Science and Technology(Approval No.HVUYL414101416920231017001)all participants signed a written informed consent.
文摘BACKGROUND Centromere protein A(CENPA)exhibits an increased expression level in primary human rectal cancer tissues,but its role has not been investigated.AIM To clarify the specific role and mechanism of CENPA in rectal cancer progression.METHODS CENPA protein expression in rectal cancer tissues and cell lines were detected.CENPA was overexpressed and knocked down in SW837 and SW480 cells,and proliferation,invasion,apoptosis and epithelial-mesenchymal transition(EMT)marker protein levels were examined.O6-methylguanine DNA methyltransferase(MGMT)promoter methylation was assessed with methylation-specific poly-merase chain reaction.Co-immunoprecipitation assay verified the interaction between MGMT and protein tyrosine phosphatase nonreceptor type 4(PTPN4).SW837 cells with CENPA knockdown were injected subcutaneously into mice,and tumor growth was examined.RESULTS CENPA was upregulated in rectal cancer tissues and cell lines.CENPA overex-pression promoted proliferation,invasion and EMT,and inhibited apoptosis in rectal cancer cells.Whereas CENPA knockdown showed the opposite results.Moreover,CENPA inhibited MGMT expression by promoting DNA methyltrans-ferase 1-mediated MGMT promoter methylation.MGMT knockdown abolished the CENPA knockdown-mediated inhibition of rectal cancer cell progression.MGMT increased PTPN4 protein stability by inhibiting PTPN4 ubiquitination degradation via competing with ubiquitin-conjugating enzyme E2O for interacting with PTPN4.PTPN4 knockdown abolished the inhibitory effects of MGMT overexpression on rectal cancer cell progression.Moreover,CENPA knockdown inhibited xenograft tumor growth in vivo.CONCLUSION CENPA knockdown inhibited rectal cancer cell growth and attenuated xenograft tumor growth through regulating the MGMT/PTPN4 axis.
文摘A thermo-insensitive pale green leaf mutant （pgl2） was isolated from T-DNA inserted transgenic lines of rice （Oryza sativa L. subsp, japonica cv. Nipponbare）. Genetic analysis indicated that the phenotype was caused by a recessive mutation in a single nuclear-encoded gene. To map the PGL2gene, an F2 population was constructed by crossing the mutant with Longtefu （Oryza sativa L. subsp, indica）. The PGL2 locus was roughly linked to SSR marker RM331 on chromosome 8. To finely map the gene, 14 new InDel markers were developed around the marker, and PGL2 was further mapped to a 2.37 Mb centromeric region. Analysis on chlorophyll contents of leaves showed that there was no obvious difference between the mutant and the wild type in total chlorophyll （Chl） content, while the ratio of Chl a / Chl b in the mutant was only about 1, which was distinctly lower than that in the wild type, suggesting that the PGL2 gene was related to the conversion between Chl a and Chl b. Moreover, the method of primer design around the centromeric region was discussed, which would provide insight into fine mapping of the functional genes in plant centromeres.
基金supported by the grants from the National Natural Science Foundation of China (Nos.31071083 and 31130033)the National Science Foundation of USA (No.DBI 0922703)
文摘Plant centromeres are generally composed of tandem arrays of simple repeats that form a complex chromosome locus where the kinetochore forms and microtubules attach during mitosis and meiosis. Each chromosome has one centromere region, which is essential for accurate division of the genetic material. Recently, chromosomes containing two centromere regions （called dicentric chromosomes） have been found in maize and wheat. Interestingly, some dicentric chromosomes are stable because only one centromere is active and the other one is inactivated. Because such arrays maintain their typical structure for both active and inactive centromeres, the specification of centromere activity has an epigenetic component independent of the DNA sequence. Under some circumstances, the inactive centromeres may recover centromere function, which is called centromere reactivation. Recent studies have highlighted the important changes, such as DNA methylation and histone modification, that occur during centromere inactivation and reactivation.
文摘Using indirect immunofluorescence (IIF), an anti-centromere protein CenpG-serum was verified. Western blot of the protein extracts of 31 samples of breast cancer tissues and their normal (not cancerous ) tissues a little far away from them in the same individuals showed that, in the majority of the tests (71%), centromere protein CenpG over expressed in breast cancer tissues. And moreover, a kind of protein component whose molecular weight is 43 kd, and which can be recognized by anti-CenpG serum was found in two of the cancer samples. The results suggested that CenpG (together whith it, there may be other relative components),which has been found and named recently, may be related to cancer,and its differential expressing is probably related to malignant cell proliferation.
基金supported by the Program for New Century Excellent Talents in University (No. NCET-07-0811)the Natural Science Foundation of China (No. 30771208)
文摘The centromere is a defining region that mediates chromosome attachment to kinetochore microtubules and proper segregation of the sister chromatids. Intriguingly, satellite DNA and centromeric retrotransposon as major DNA constituents of centromere showed baffling diversification and species-specific. However, the key kinetochore proteins are conserved in both plants and animals, particularly the centromere-specific histone H3-1ike protein （CENH3） in all functional centromeres. Recent studies have highlighted the importance of epigenetic mechanisms in the establishment and maintenance of centromere identity. Here, we review the progress and compendium of research on plant centromere in the light of recent data.
文摘The centromere is an essential chromosome site at which the kinetochore forms and loads proteins needed for faithful segregation during the cell cycle and meiosis（Houben et al., 1999;Cleveland et al.,2003;Ma et al.,2007;Birchler and Han,2009）.Centromere specific sequences such as tandem repeats or transposable elements evolve quickly both within and between the species but have conserved kinetochore proteins（Henikoff and Furuyama,2010）.
基金supported by the Natural Science Foundation of Shanxi province[2012021035-1]
文摘Objective To investigate the expression of centromere protein-C （CENP-C） in villus tissue of the first-trimester spontaneous abortion （SA） and the correlation study of CENP-C expression with chromosome segregation. Methods Fluorescence in situ hybridization （FISH） and G-banded karyotype analysis were used to detect the numerical chromosome abnormality in 94 villus tissues of women with SA. The participants were separated into case group （n=30） and control group （n--30） according to the results with FISH. The qRT-PCR and Western blotting analysis were used to assess the expression level of CENP-C. Results Forty-eight （51.06%） cases had observed the numerical chromosome abnormality, including 30positive cases and the positive rate was 31.91%. The main types of variation included trisomy 16, 21, 22, X monosomy and triploid. The expression levels of CENP-C mRNA and protein in case group were statistically higher than that in control group （P〈0.05）. Conclusion Expression of CENP-C in the villus tissues of women might be related to SA induced by chromosomal aneuploid.
文摘Recently the antichromosome antisera from several scleroderma patients have been found to recognize the pellicle of metaphase and anaphase chromosomes. In order to identify the pellicle components, we used these antichromosome antisera to screen a human embryonic cDNA library. The sequences of the positive clones are identical to the cDNA gene sequence of CENP-C (centromere protein C), a human centromere autoantigen. This result suggusts that CENP-C is a component of the pellicle of human metaphase and anaphase chromosomes.
基金supported by grants from the National Natural Science Foundation of China (Nos. U1302261, 31360260 and 31401357).
文摘An awned rice（Oryza sativa） plant carrying a tiny extra chromosome was discovered among the progeny of a telotrisomic line 2nt4L. Fluorescence in situ hybridization（FISH） using chromosome specific BAC clones revealed that this extra chromosome was a ring chromosome derived from part of the long arm of chromosome 4. So the aneuploidy plant was accordingly named as 2nt4L ring. We did not detect any Cent O FISH signals on the ring chromosome, and found only the centromeric probe Centromeric Retrotransposon of Rice（CRR） was co-localized with the centromere-specific histone CENH3 as revealed by sequential FISH after immunodetection. The extra ring chromosome exhibited a unique segregation pattern during meiosis, including no pairing between the ring chromosome and normal chromosome 4during prophase I and pre-separation of sister chromatids at anaphase I.
基金the National Natural Science Foundation of China(31991212)the National Key Research and Development Program of China(2022YFF1003303).
文摘The Triticum-Aegilops complex groups demonstrated high cross-affinity with each other to overcome the barriers of distant hybridization(Loureiro et al.,2023).Distant hybridization involves two distinct yet closely related events:hybridization and genome doubling.Previous studies have indicated that bursts of transposable elements(TEs)can occur as a consequence or concomitant to hybridization or genome duplication(Parisod et al.,2010).This raises an important scientific question regarding how the TEs-rich centromere region copes with genomic shock(McClintock,1984).The Triticum-Aegilops species complexes,particularly in the F1,So,and subsequent early generations resulting from successive selfcrossing,offer an opportunity to investigate whether the centromere environment undergoes reconstruction and the associated mechanisms that maintain genomic stability.
文摘The aneuploid with isochromosome or telochromosome is ideal material for exploring the position of centromere in lingkage map. FOr obtaining these aneuploids in rice, the primary trisomics from triplo-1 to triplo-12 and the aneuploids derived from a triploid of indica rice variety Zhongxian 3037 were carefully investigated. From the offsprings of triplo-10, a primary trisomic of chromosome 10 of the variety, an isotetrasomic "triplo-10-1" was obtained. Cytological investigation revealed that a pair of extra isochromosomes of triplo-10-1 were come from the short arm of chromosome 10. In the offsprings of the isotetrasomic, a secondary trisomic "triplo-10-2" 5 in which the extra- chromosome was an isochromosome derived from the short arm of chromosome 10, was identified. With the isotetrasomic, secondary trisomic, primary trisomic and diploid of variety Zhongxian 3037, different molecular markers were used for exploring the position of the centromere of chromosome 10. Based on the DNA dosage effect, it was verified that the molecular markers G1125, G333 and L169 were located on the short arm, G1084 and other 16 available molecular markers were on the long arm of chromosome 10. So the centromere of chromosome 10 was located somewhere betweenG1125 and G1084 according to the RFLP linkage map given by Kurata et al[1]. The distance from G1125 to G1084 was about 3.2cM.
基金supported by the grants from the National Natural Science Foundation of China(Nos.31576124,31071382 and 30771210)the National Basic Research Program of China(973 Program,Nos.2010CB125904 and 2013CBA01405)
文摘The centromere of eukaryotic chromosomes is the crucial locus responsible for sister chromatid cohesion and for correct segregation of chromosomes to daughter cells during cell division. In the structural genomics era, centromeres represent the last frontiers of higher eukaryotic genomes because of their densely methylated, highly repetitive and, heterochromatic DNA （Hall et al., 2004）. Although these functions are conserved among all eukaryotes, centromeric DNA sequences are evolving rapidly （Jiang et al., 2003）.
基金supported by the National Key Research and Development Program of China(2023YFD2301201)the Key Research and Development Project of Henan Province(231111110400)+1 种基金Major Science and Technology Projects of Xinjiang Uygur Autonomous Region(2023A02001)the Fundamental Research Funds of State Key Laboratory of Cotton Bio-breeding and Integrated Utilization(CB202406)。
文摘Polyploidization is recognized as a powerful driver of plant evolution and domestication.In the genus Gossypium,the natural hybridization of an A-genome ancestor and a D-genome ancestor gave rise to allopolyploid cottons(Huang et al.,2024),such as Gossypium hirsutum and Gossypium barbadense.Previous cotton reference genomes(Du et al.,2018;Hu et al.,2019;Huang et al.,2020;Li et al.,2015;Wang et al.,2019;Yang et al.,2019;Zhang et al.,2015),although instrumental to cotton genetics and breeding,contained large assembly gaps,especially repetitive regions like centromeres.
基金supported by the Central Public-Interest Scientific Institution Basal Research Fund(Y2023QC07)the Chinese Academy of Agricultural Sciences Innovation Project(CAAS-ASTIP-IVFCAAS)the China Agricultural Research System(CARS-23-A-17).
文摘Dear Editor,Spinach(Spinacia oleracea L.)is a diploid plant with n=6 chromosomes(2n=12)and is one of the world’s most important green leafy vegetables.The genus Spinacia is well suited for studying sex chromosome evolution because it is dioecious,has an XY sex determination system,and includes two wild species(She et al.,2023).The first chromosome-level spinach genome,assembled using next-generation sequencing reads in 2017,had only 47%of the sequence anchored to the chromosomes(Xu et al.,2017).
基金supported by grants from the Biological Breeding-National Science and Technology Major Project(2024ZD04079)the National Natural Science Foundation of China(32370261).
文摘Dear Editor,Legumes,including soybean and alfalfa,are vital agricultural crops worldwide,providing high-quality protein and oil sources for humans and animals.In addition,legumes also provide nitrogen for soil improvement,benefiting from their symbiotic associations with nitrogen-fixing bacteria.
基金supported by the National Natural Science Foundation of China(32230029,81925015,32270898,32400709,and 32400714)the National Key Research and Development Program of China(2022YFC2702600)+2 种基金the China Postdoctoral Science Foundation(2024M760638 and 2024M760640)the Science and Technology Project of Guangzhou(2023A03J0886)the plan on enhancing scientific research in GMU.
文摘R-loops play various roles in many physiological processes,however,their role in meiotic division remains largely unknown.Here we show that R-loops and their regulator RNase H1 are present at centromeres during oocyte meiotic divisions.Proper centromeric R-loops are essential to ensure chromosome alignment in oocytes during metaphase I(MI).Remarkably,both Rnaseh1 knockout and overexpression in oocytes lead to severe spindle assembly defects and chromosome misalignment due to dysregulation of R-loops at centromeres.Furthermore,we find that replication protein A(RPA)is recruited to centromeric R-loops,facilitating the deposition of ataxia telangiectasia-mutated and Rad3-related(ATR)kinase at centromeres by interacting with the ATR-interaction protein(ATRIP).The ATR kinase deposition triggers the activity of CHK1,stimulating the phosphorylation of Aurora B to finally promote proper spindle assembly and chromosome alignment at the equatorial plate.Most importantly,the application of ATR,CHK1,and Aurora B inhibitors could efficiently rescue the defects in spindle assembly and chromosome alignment due to RNase H1 deficiency in oocytes.Overall,our findings uncover a critical role of R-loops during mouse oocyte meiotic divisions,suggesting that dysregulation of R-loops may be associated with female infertility.Additionally,ATR,CHK1,and Aurora B inhibitors may potentially be used to treat some infertile patients.
基金supported by the National Natural Science Foundation of China(Grant No.31071083)National Science Foundation(No.DBI0922703).
文摘The centromere is a highly organized structure mainly composed of repeat sequences,which make this region extremely difficult for sequencing and other analyses.It plays a conserved role in equal division of chromosomes into daughter cells in both mitosis and meiosis.However,centromere sequences show notable plasticity.In a dicentric chromosome,one of the centromeres can become inactivated with the underlying DNA unchanged.Furthermore,formerly inactive centromeres can regain activity under certain conditions.In addition,neocentromeres without centromeric repeats have been found in a wide spectrum of species.This evidence indicates that epigenetic mechanisms together with centromeric sequences are associated with centromere specification.
基金supported by the National Key Research and Development Program of China(2021YFA0909300)the General Research Fund(17124922)from Hong Kong Research Grants Councilthe University of Hong Kong Seed Funds for Basic Research(funded in 2019).
文摘During cell division,the accurate capture of sister kinetochores that are built on the centromeres of chromosomes by microtubules emanating from opposite spindle poles governs faithful chromosome segregation.To ensure sister chromatids separate correctly,sister centromeres undergo resolution to achieve bipolar orientation prior to microtubule attachments.Failure of centromere resolution increases the frequency of merotelic attachments,with microtubules from opposite poles attaching to the same sister kinetochore,causing lagging chromosome,aneuploidy,and even cancer progression.The Aurora B-mediated tension-sensing machinery to correct erroneous kinetochore-microtubule attachments has been well studied.However,preventative mechanisms to avoid merotelic attachments that occurin the earlier mitotic stage are poorly understood.In this study,we found that inactivation of mitotickinase Aurora B/AIR-2 increases merotelic attachments in Caenorhabditis elegans.On one hand,Aurora B/AIR-2-deficient cells exhibit a delay in the occurrence of centromere resolution and a disruption in targeting condensin Il components to chromatin.On the other hand,loss of Aurora B/AIR-2 results in an increased localization of centromeric proteins CENP-A/HCP-3 and M18BP1/KNL-2 as well as the kinetochore protein MiS-12 on chromatin,which may generate ectopic kinetochores causing erroneous attachments.To conclude,this study elucidated that Aurora B/AIR-2 regulates sister centromere resolution and CENP-A/HCP-3 deposition to actively prevent merotely and chromosome instability in cells.
基金This research was supported by the Natinal Key Research and Development Program of China(2016YFD0100904 and 2016YFD0100802)the National Natural Science Foundation of China(31871269)+1 种基金the Hubei Provincial Natural Science Foundation of China(2019CFA014)Fundamental Research Funds for the Central Universities(2662020SKPY010 to J.Z.).
文摘Rice(Oryza sativa),a major staple throughout the world and a model system for plant genomics and breeding,was the first crop genome sequenced almost two decades ago.However,reference genomes for all higher organisms to date contain gaps and missing sequences.Here,we report the assembly and analysis of gap-free reference genome sequences for two elite O.sativa xian/indica rice varieties,Zhenshan 97 and Minghui 63,which are being used as a model system for studying heterosis and yield.Gap-free reference genomes provide the opportunity for a global view of the structure and function of centromeres.We show that all rice centromeric regions share conserved centromere-specific satellite motifs with different copy numbers and structures.In addition,the similarity of CentO repeats in the same chromosome is higher than across chromosomes,supporting a model of local expansion and homogenization.Both genomes have over 395 non-TE genes located in centromere regions,of which∼41%are actively transcribed.Two large structural variants at the end of chromosome 11 affect the copy number of resistance genes between the two genomes.The availability of the two gap-free genomes lays a solid foundation for further understanding genome structure and function in plants and breeding climate-resilient varieties.
文摘Although the centromeres of some plants have been investlgated prevlously, our knowledge of the wheat centromere Is still very llmlted. To understand the structure and functlon of the wheat centromere, we used two centromeric repeats （RCS1 and CCS1-5ab） to obtain some centromere-assoclated bacterial artificial chromosome （BAC） clones in 32 RCS1-related BAC clones that had been screened out from a diploid wheat （Triticum boeoticum Boiss.; 2n=2x=14） BAC library. Southern hybridization results indicated that, of the 32 candidates, there were 28 RCS1-positive clones. Based on gel blot patterns, the frequency of RCS1 was approximately one copy every 69.4 kb in these 28 RCS1-positive BAC clones. More bands were detected when the same filter was probed with CCS1-5ab. Furthermore, the CCS1 bands covered all the bands detected by RCS1, which suggests that some CCS1 repeats were distributed together with RCS1. The frequency of CCS1 families was once every 35.8 kb, nearly twice that of RCS1. Fluorescence in situ hybridization （FISH） analysis Indicated that the five BAC clones containing RCS1 and CCS1 sequences all detected signals at the centromerlc regions in hexaplold wheat, but the signal intensities on the A-genome chromosomes were stronger than those on the B- and/or Dgenome chromosomes. The FISH analysis among nine Triticeae cereals indicated that there were A-genomespecific （or rich） sequences dispersing on chromosome arms in the BAC clone TbBACS. In addition, at the interphase cells, the centromeres of diploid species usually clustered at one pole and formed a ring-like allocation In the period before metaphase.
