染色質(zhì)是真核生物遺傳物質(zhì)的包裝形式,。按照其包裝的致密程度,，染色質(zhì)可分為較為松散的常染色質(zhì)和較為致密的異染色質(zhì),。異染色質(zhì)的這種結(jié)構(gòu)特征不利于蛋白質(zhì)的招募，因而可能會危及到正常的異染色質(zhì)DNA代謝過程,，例如DNA復(fù)制和重組,。
1月13日，PLoS Genetics雜志發(fā)表了上海生科院生化與細胞所周金秋研究組關(guān)于釀酒酵母異染色質(zhì)組蛋白標記的文章,。他們發(fā)現(xiàn)組蛋白乙?；笍?fù)合物NuA4能夠被招募到端粒異染色質(zhì)區(qū)，并特異性地乙?；M蛋白H4第12位賴氨酸,。該位點的乙酰化對端粒異染色質(zhì)的基本DNA代謝過程起調(diào)控作用,。這一研究表明,，異染色質(zhì)并不像人們以往認為的那樣“靜默”，它同樣具備可塑性,，而這種異染色質(zhì)的可塑性直接歸因于它自身的化學(xué)性質(zhì),。
該論文是由周金秋研究組的助理研究員周波和博士研究生王珊珊等完成。該課題獲得了國家科技部和國家自然科學(xué)基金委的經(jīng)費資助,。（生物谷Bioon.com）
生物谷推薦原文出處：
PLoS Genet 7(1): e1001272. doi:10.1371/journal.pgen.1001272
Histone H4 Lysine 12 Acetylation Regulates Telomeric Heterochromatin Plasticity in Saccharomyces cerevisiae
Bo O. Zhou1, Shan-Shan Wang1, Yang Zhang1, Xiao-Hong Fu1, Wei Dang1, Brian A. Lenzmeier2, Jin-Qiu Zhou1*
1 State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China, 2 School of Science, Buena Vista University, Storm Lake, Iowa, United States of America
Abstract
Recent studies have established that the highly condensed and transcriptionally silent heterochromatic domains in budding yeast are virtually dynamic structures. The underlying mechanisms for heterochromatin dynamics, however, remain obscure. In this study, we show that histones are dynamically acetylated on H4K12 at telomeric heterochromatin, and this acetylation regulates several of the dynamic telomere properties. Using a de novo heterochromatin formation assay, we surprisingly found that acetylated H4K12 survived the formation of telomeric heterochromatin. Consistently, the histone acetyltransferase complex NuA4 bound to silenced telomeric regions and acetylated H4K12. H4K12 acetylation prevented the over-accumulation of Sir proteins at telomeric heterochromatin and elimination of this acetylation caused defects in multiple telomere-related processes, including transcription, telomere replication, and recombination. Together, these data shed light on a potential histone acetylation mark within telomeric heterochromatin that contributes to telomere plasticity.
