染色质构象调控真核基因的表达

摘要

真核基因的表达受到各种顺式调控元件、反式作用因子、染色质DNA以及组蛋白表观遗传修饰等多因素、多层次的调控.染色质三维空间结构的变化在调控真核基因表达方面也发挥了至关重要的作用.染色质构象的变化一方面可以使增强子等调控元件与靶基因相互靠近,从而促进基因表达；同时也可能通过形成空间位阻结构阻碍调控元件作用于靶基因,抑制基因表达.虽然染色质结构变化调控真核基因表达的机制仍缺乏较为精确的分子模型,但在组蛋白修饰、核小体定位、染色体领域以及染色质间相互作用等表观遗传学研究中,已经发现有诸多证据支持染色质构象在真核基因表达调控中的重要地位.文章主要综述了染色质结构及其构象的变化等对真核基因表达调控的影响.%Gene expression in eukaryotes is regulated at multiple levels, which involves various cis-regulatory elements and trans-acting factors at transcriptional level. In addition, DNA methylation and histone modifications also play crucial roles in epigenetic regulation of eukaryotic genes. It is pivotal for evaluating the regulation of gene expression to understand the structural properties and spatial organization of chromatin at 3-D level. The dynamic alternations of chromatin conformation can either activate gene expression by facilitating the interactions between enhancers or other cis-regulatory elements and their target genes or suppress gene expression by blocking the interactions due to steric hindrance. Although the precise molecular mechanisms underlying the gene regulation via conformational changes of chromatin remain obscure, epigenetic studies including histone modification, nucleosome positioning, chromosome territories as well as chromatin interactions, have provided accumulating evidence to demonstrate the significance of chromatin conformation in eukaryotic gene regulation. Here, we reviewed the recent advances on the role of dynamic alterations of chromatin in gene regulation , which occur at different levels from the primary structure to three dimensional conformation.