Nature2014-06-26 5:53 PM

“Cohesin”加载方式的重现 Biochemical reconstitution of topological DNA binding by the cohesin ring


很多细胞DNA过程都要求染色体被一个名叫 “cohesin”的环形蛋白聚在一起。尽管它很重要,但这一反应以前并没有在体外被完全重现。现在,Yasuto Murayama和Frank Uhlmann用纯化的裂殖酵母蛋白成功重现了“cohesin”加载。他们的数据让我们看到了“加载体复合物”是怎样介导“cohesin”在DNA上的拓扑结合的,同时也为对姐妹染色单体的凝聚是怎样形成的做进一步的机制性研究打下了基础。


Cohesion between sister chromatids, mediated by the chromosomal cohesin complex, is a prerequisite for faithful chromosome segregation in mitosis. Cohesin also has vital roles in DNA repair and transcriptional regulation. The ring-shaped cohesin complex is thought to encircle sister DNA strands, but its molecular mechanism of action is poorly understood and the biochemical reconstitution of cohesin activity in vitro has remained an unattained goal. Here we reconstitute cohesin loading onto DNA using purified fission yeast cohesin and its loader complex, Mis4Scc2–Ssl3Scc4 (Schizosaccharomyces pombe gene names appear throughout with their more commonly known Saccharomyces cerevisiae counterparts added in superscript). Incubation of cohesin with DNA leads to spontaneous topological loading, but this remains inefficient. The loader contacts cohesin at multiple sites around the ring circumference, including the hitherto enigmatic Psc3Scc3 subunit, and stimulates cohesin’s ATPase, resulting in efficient topological loading. The in vitro reconstitution of cohesin loading onto DNA provides mechanistic insight into the initial steps of the establishment of sister chromatid cohesion and other chromosomal processes mediated by cohesion.






Nature Magazine

0 Following 27 Fans 0 Projects 626 Articles


Meristems encompass stem/progenitor cells that sustain postembryonic growth of all plant organs. How meristems are activated and sustained by nutrient

Read More

Transcription of ribosomal RNA by RNA polymerase (Pol) I initiates ribosome biogenesis and regulates eukaryotic cell growth. The crystal structure of P

Read More

Abstract The effect of anthropogenic aerosols on cloud droplet concentrations and radiative properties is the source of one of the largest uncertainti

Read More

Abstract Ecological and societal disruptions by modern climate change are critically determined by the time frame over which climates shift beyond his

Read More

Abstract Evidence from Greenland ice cores shows that year-to-year temperature variability was probably higher in some past cold periods, but there is

Read More

Abstract The land and ocean act as a sink for fossil-fuel emissions, thereby slowing the rise of atmospheric carbon dioxide concentrations1. Although t

Read More

论文摘要 人们已经非常清楚生物多样性对初级生产力等生态系统功能有一个积极影响,但它对植物凋落物的多样性和分解植物凋落物的生物的多样性的影响却不是很清楚。Stephan H?ttenschwiler及同事对从亚北极到热带、包括水生生态系统和陆地生态系统在内的五个地点所进行的并行操纵实验中的凋落物多样性进

Read More

论文摘要 FANTOM5 (即“哺乳动物基因组-5的功能注解”) 是一个大型国际合作项目的第5大阶段,其目标是分析定义每个人类细胞类型的转录调控网络。本期Nature上的两篇Articles论文发表了该项目的一些最新结果。第一篇论文利用FANTOM5项目组的组织和原代细胞样本来定义整个人体中活性的、在

Read More

论文摘要 有证据表明,血管 (尤其是它们的内皮细胞) 控制器官的生长、平衡和再生。在本期Nature上发表的两篇论文中,Ralf Adams及同事证明,骨头血管含有专门支持骨成熟和再生的内皮细胞。Anjali Kusumbe等人在小鼠骨骼系统内识别出一个在介导骨生长中起关键作用的毛细血管亚型。这些血管

Read More

论文摘要 CD4 T细胞(携带能够识别被病毒感染的细胞表面上的CD4抗原的受体的辅助T细胞)的丧失是艾滋病发病的根源。在这项研究中,Warner Greene等人识别出静止的淋巴CD4 T细胞在HIV感染过程中被耗尽的机制。利用保持了天然淋巴环境的人淋巴组织的体外培养,本文作者发现,失败的病毒复制触发

Read More