The frequency of aneuploid gamete formation increases with maternal age,yet the effects of genetic variants on meiotic chromosome segregation accuracy during aging remain poorly understood.Using the multicellular orga...The frequency of aneuploid gamete formation increases with maternal age,yet the effects of genetic variants on meiotic chromosome segregation accuracy during aging remain poorly understood.Using the multicellular organism Caenorhabditis elegans,we investigate the impact of mutations in the conserved cohesin complex on age-associated meiotic errors.Point mutations in the head domain of the cohesin component SMC-1,which alter local hydrophobicity,cause meiotic defects that vary with age.A severe mutation causes incomplete synapsis and defective crossover formation,and a minor one causes age-related diakinesis bivalent abnormalities.Notably,while the mild mutation causes defects only in aged worms,worms with the severe mutation exhibit significantly alleviated phenotypes with age.Genetic and cytological analyses suggest that this alleviation results from a slowed meiotic progression during early prophase,which restores impaired cohesin loading.These findings reveal that cohesin variants,meiotic progression speed during early prophase,and the overall duration of meiosis collectively shape the accuracy of meiotic chromosome segregation.展开更多
In eukaryotic organisms,the three-dimensional organization and epigenomic landscape of chromatin are fundamental to the regulation of gene expression.Previous studies have provided significant insights into CpG methyl...In eukaryotic organisms,the three-dimensional organization and epigenomic landscape of chromatin are fundamental to the regulation of gene expression.Previous studies have provided significant insights into CpG methylation,chromatin accessibility,and the dynamics of 3D architecture.However,a systematic delineation of how these epigenomic features regulate transcriptional activity remains limited.In this study,we develop nanoCAM-seq,a single-molecule sequencing technique designed to simultaneously profile higher-order chromatin interactions,chromatin accessibility,and endogenous CpG methylation.This approach provides an integrative view of chromatin features associated with cis-regulatory elements and reveals their coordinated dynamics during transitions of A/B compartments.Single-molecule analyses using nanoCAM-seq further reveal that promoters characterized by low CpG methylation and high chromatin accessibility more frequently interact with multiple enhancers.Collectively,our findings establish nanoCAM-seq as a powerful approach for resolving the coordinated dynamics of chromatin architecture and epigenetic modifications,offering critical insights into the regulatory mechanisms underlying gene expression.展开更多
对锦鸡儿属植物根尖染色体制片中的几种预处理、解离、染色方法进行了比较.结果表明,用0.002 m o l/L8-羟基喹啉和饱和对二氯苯混和液(1∶1)预处理,1 m o l/L HC l预热60℃解离,改良苯酚品红染色效果较好.对锦鸡儿属植物3个种的体细胞...对锦鸡儿属植物根尖染色体制片中的几种预处理、解离、染色方法进行了比较.结果表明,用0.002 m o l/L8-羟基喹啉和饱和对二氯苯混和液(1∶1)预处理,1 m o l/L HC l预热60℃解离,改良苯酚品红染色效果较好.对锦鸡儿属植物3个种的体细胞中期染色体制片,核型分析结果表明,小叶锦鸡儿(C arag ana m icrophy lla)为2n=2x=16=8m(2SAT)+4sm+4M,中间锦鸡儿(C.interm ed ia)为2n=2x=16=6m+8sm+2M,青海锦鸡儿(C.ch ing-ha iensis)为2n=2x=16=4m+8sm+4M+2B,核型不对称性为“2A”型.此外,还发现这3种植物的根尖细胞中均有内源有丝分裂现象.展开更多
基金supported by grants from the National Natural Science Foundation of China(32370780 and 32022018)the National Key Research and Development Program of China(2021YFA1101001)+1 种基金the Taishan Scholars Program Special FundSome strains were provided by the CGC,which is funded by NIH Office of Research Infrastructure Programs(P40 OD010440).
文摘The frequency of aneuploid gamete formation increases with maternal age,yet the effects of genetic variants on meiotic chromosome segregation accuracy during aging remain poorly understood.Using the multicellular organism Caenorhabditis elegans,we investigate the impact of mutations in the conserved cohesin complex on age-associated meiotic errors.Point mutations in the head domain of the cohesin component SMC-1,which alter local hydrophobicity,cause meiotic defects that vary with age.A severe mutation causes incomplete synapsis and defective crossover formation,and a minor one causes age-related diakinesis bivalent abnormalities.Notably,while the mild mutation causes defects only in aged worms,worms with the severe mutation exhibit significantly alleviated phenotypes with age.Genetic and cytological analyses suggest that this alleviation results from a slowed meiotic progression during early prophase,which restores impaired cohesin loading.These findings reveal that cohesin variants,meiotic progression speed during early prophase,and the overall duration of meiosis collectively shape the accuracy of meiotic chromosome segregation.
基金supported by grants from the Key Project Fund of National Natural Science Foundation of China(82230031)the Regional Innovation and Development Joint Fund of the National Natural Science Foundation of China(No.U24A200954)+4 种基金the Key Special Project of‘Cutting-Edge Biotechnology’in the National Key Research and Development Program of China(2024YFC3406200)Sanming Project of Medicine in Shenzhen(SZSM202411007)Guangdong Basic and Applied Basic Research Foundation Regional Joint Fund Key Program(2023B1515120051)Shenzhen Bay Laboratory Basic Research(SZBK2021080601009)to Wei Chithe Youth Fund of the National Natural Science Foundation of China(No.32300515)to Longjian Niu.
文摘In eukaryotic organisms,the three-dimensional organization and epigenomic landscape of chromatin are fundamental to the regulation of gene expression.Previous studies have provided significant insights into CpG methylation,chromatin accessibility,and the dynamics of 3D architecture.However,a systematic delineation of how these epigenomic features regulate transcriptional activity remains limited.In this study,we develop nanoCAM-seq,a single-molecule sequencing technique designed to simultaneously profile higher-order chromatin interactions,chromatin accessibility,and endogenous CpG methylation.This approach provides an integrative view of chromatin features associated with cis-regulatory elements and reveals their coordinated dynamics during transitions of A/B compartments.Single-molecule analyses using nanoCAM-seq further reveal that promoters characterized by low CpG methylation and high chromatin accessibility more frequently interact with multiple enhancers.Collectively,our findings establish nanoCAM-seq as a powerful approach for resolving the coordinated dynamics of chromatin architecture and epigenetic modifications,offering critical insights into the regulatory mechanisms underlying gene expression.
文摘对锦鸡儿属植物根尖染色体制片中的几种预处理、解离、染色方法进行了比较.结果表明,用0.002 m o l/L8-羟基喹啉和饱和对二氯苯混和液(1∶1)预处理,1 m o l/L HC l预热60℃解离,改良苯酚品红染色效果较好.对锦鸡儿属植物3个种的体细胞中期染色体制片,核型分析结果表明,小叶锦鸡儿(C arag ana m icrophy lla)为2n=2x=16=8m(2SAT)+4sm+4M,中间锦鸡儿(C.interm ed ia)为2n=2x=16=6m+8sm+2M,青海锦鸡儿(C.ch ing-ha iensis)为2n=2x=16=4m+8sm+4M+2B,核型不对称性为“2A”型.此外,还发现这3种植物的根尖细胞中均有内源有丝分裂现象.
