Mechanics of Sister Chromatids studied with a Polymer Model

Frontiers in Physics

Heermann, Dieter W¹  Zhang, Yang²  Isbaner, Sebastian² 

[1] German Cancer Research Center (DKFZ), Heidelberg, Germany;Heidelberg University, Institute for Theoretical Physics, Philosophenweg 19, Heidelberg, D-69120, Germany

关键词: Chromosomes;    cohesion;    sister chromatids;    polymer model;    Mechanical Properties;   

DOI  :  10.3389/fphy.2013.00016

学科分类：物理（综合）

来源: Frontiers

【 摘 要 】

Sister chromatid cohesion denotes the phenomenon that sister chromatids are initially attached to each other in mitosis to guarantee the error-free distribution into the daughter cells. Cohesion is mediated by binding proteins and only resolved after mitotic chromosome condensation is completed. However, the amount of attachement points required to maintain sister chromatid cohesion while still allowing proper chromosome condensation is not known yet. Additionally the impact of cohesion on the mechanical properties of chromosomes also poses an interesting problem. In this work we study the conformational and mechanical properties of sister chromatids by means of computer simulations. We model both protein-mediated cohesion between sister chromatids and chromosome condensation with a dynamic binding mechanisms. We show in a phase diagram that only specific link concentrations lead to connected and fully condensed chromatids that do not intermingle with each other nor separate due to entropic forces. Furthermore we show that dynamic bonding between chromatids decrease the Young's modulus compared to non-bonded chromatids.

【 授权许可】

CC BY