Deposition-related sites K5/K12 in histone H4 are not required for nucleosome deposition in yeast
Deposition-related sites K5/K12 in histone H4 are not required for nucleosome deposition in yeast
复制标题
DOI：
10.1073/pnas.95.12.6693
复制
发表时间：
1998-06-09
影响因子：
11.1
通讯作者：
Grunstein, M
中科院分区：
文献类型：
--
作者：
Ma, XJ;Wu, JS;Grunstein, M
组蛋白H4可以在N-末端赖氨酸K5、K8、K12和K16处被乙酰化，但在不同的生物体中，新合成的H4在K5/K12处被双乙酰化。这种模式被广泛认为是重要的组蛋白沉积到复制DNA。为了研究K5/K12的重要性，我们对酵母中的这些赖氨酸进行了诱变，并测定了核小体组装。在组蛋白H_3 N端缺失的情况下进行分析，其在组蛋白沉积中具有与H_4的功能冗余的功能。因为核小体的消耗可能是致命的，所以我们检测了细胞活力。我们还通过检查全细胞中的质粒超螺旋密度和酵母细胞提取物中的超螺旋来分析体内和体外核小体组装。所有这三种方法都表明，诱变K5和K12在体内或体外不能阻止细胞生长和组蛋白沉积。因此，K5/K12不是酵母中核小体组装所必需的。只有当乙酰化的前三个位点K5、K8和K12同时被诱变时，才发生致死性，并且在体内和体外组装都最强烈地减少。这些数据证明了酵母组蛋白H4沉积中K5、K8和K12位点的冗余性。
Histone H4 can be acetylated at N-terminal lysines K5, K8, K12, and K16, but newly synthesized H4 is diacetylated at K5/K12 in diverse organisms. This pattern is widely thought to be important for histone deposition onto replicating DNA. To investigate the importance of K5/K12 we have mutagenized these lysines in yeast and assayed for nucleosome assembly. Assaying was done in the absence of the histone H3 N terminus, which has functions redundant with those of H4 in histone deposition, Nucleosome assembly was assayed by three methods. Because nucleosome depletion may be lethal,,ve examined cell viability. We also analyzed nucleosome assembly in vivo and in vitro by examining plasmid superhelicity density in whole cells and supercoiling in yeast cell extracts. All three approaches demonstrate that mutagenizing K5 and K12 together does not prevent cell growth and histone deposition in vivo or in vitro. Therefore, K5/K12 cannot be required for nucleosome assembly in yeast, It is only when the first three sites of acetylation-K5, K8, and K12-are mutagenized simultaneously that lethality occurs and assembly is most strongly decreased both irt vivo and in vitro. These data argue for the redundancy of sites K5, K8, and K12 in the deposition of yeast histone H4.