Cohesin是一种异源五聚体蛋白复合物,有助于染色体结构和功能的各个方面,如姐妹染色单体内聚力,基因组压缩,和DNA损伤反应。以前的研究提供了大量的信息,关于建筑群的建筑和区域结构,但是整个cohesin复合体的配置和结构动力学仍然是未知的,部分是由于其卷曲螺旋的灵活性。我们使用体内功能突变补偿研究了粘附蛋白的组织和动力学。具体来说,我们开发并应用了基因抑制筛选方法,以鉴定cohesin复合物基因中的第二突变,这些突变挽救了由cohesin复合物中各种位点特异性异常引起的致死性.对这些错义抑制子突变的功能分析揭示了粘附蛋白的新特征。这里,我们总结了最近的基因抑制子筛选结果和见解:1)持有染色体DNA时,粘附蛋白的结构组织;2)粘附蛋白头-kleisin和铰链之间的相互作用;3)ATP驱动的粘附蛋白构象变化用于基因组包装。
Cohesin is a heteropentameric protein complex that contributes to various aspects of chromosome structure and function, such as sister chromatid cohesion, genome compaction, and DNA damage response. Previous studies have provided abundant information on architecture and regional structures of the cohesin complex, but the configuration and structural dynamics of the whole cohesin complex are still largely unknown, partly due to flexibility of its coiled coils. We studied cohesin organization and dynamics using in vivo functional mutation compensation. Specifically, we developed and applied genetic suppressor screening methods to identify second mutations in cohesin complex genes that rescue lethality caused by various site-specific abnormalities in the cohesin complex. Functional analysis of these missense suppressor mutations revealed novel features of cohesin. Here, we summarize recent genetic suppressor screening results and insights into: 1) cohesin\'s structural organization when holding chromosomal DNAs; 2) interaction between cohesin head-kleisin and hinge; 3) ATP-driven cohesin conformational changes for genome packaging.