小柯机器人

负责DNA环挤出的集缩素复合物可以穿过彼此
2020-03-07 16:21

2020年3月4日,荷兰代尔夫特理工大学Cees Dekker课题组在《自然》杂志在线发表论文,揭示了负责DNA环挤出的集缩素复合物可以穿过彼此。

研究人员使用延时单分子可视化来研究了两个DNA环挤压酵母集缩素之间的相互影响。他们发现,这些运动蛋白只能沿一个方向挤出DNA,即使彼此相距很远,它们也只能动态改变彼此的DNA环大小。
 
当它们紧密靠近时,集缩素复合物能够相互穿越并形成环状结构,这被称之为Z环-三个双链DNA螺旋,每个边缘与一个集缩素平行排列。Z环可以填补单环留下的缺口,并可以形成对称的二聚体马达,从两侧吸引DNA。
 
这些发现表明,集缩素可以使用多种环结构实现染色体紧缩。
 
据介绍,集缩素是染色体结构维持蛋白复合物的关键组成部分,最近被证明是一种挤压DNA环的马达分子。然而,目前尚不清楚集缩素蛋白复合物如何协同作用以将DNA共同包装成染色体。
 
附:英文原文

Title: DNA-loop extruding condensin complexes can traverse one another

Author: Eugene Kim, Jacob Kerssemakers, Indra A. Shaltiel, Christian H. Haering, Cees Dekker

Issue&Volume: 2020-03-04

Abstract: Condensin, a key component of the structure maintenance of chromosome (SMC) protein complexes, has recently been shown to be a motor that extrudes loops of DNA1. It remains unclear, however, how condensin complexes work together to collectively package DNA into chromosomes. Here we use time-lapse single-molecule visualization to study mutual interactions between two DNA-loop-extruding yeast condensins. We find that these motor proteins, which, individually, extrude DNA in one direction only are able to dynamically change each other’s DNA loop sizes, even when far apart. When they are in close proximity, condensin complexes are able to traverse each other and form a loop structure, which we term a Z-loop—three double-stranded DNA helices aligned in parallel with one condensin at each edge. Z-loops can fill gaps left by single loops and can form symmetric dimer motors that pull in DNA from both sides. These findings indicate that condensin may achieve chromosomal compaction using a variety of looping structures.

DOI: 10.1038/s41586-020-2067-5

Source: https://www.nature.com/articles/s41586-020-2067-5

Nature:《自然》,创刊于1869年。隶属于施普林格·自然出版集团,最新IF:43.07
官方网址:http://www.nature.com/
投稿链接:http://www.nature.com/authors/submit_manuscript.html


本期文章:《自然》:Online/在线发表

分享到:

0