Essential and redundant functions of histone acetylation revealed by mutation of target lysines and loss of the Gcn5p acetyltransferase
Essential and redundant functions of histone acetylation revealed by mutation of target lysines and loss of the Gcn5p acetyltransferase
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DOI：
10.1093/emboj/17.11.3155
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发表时间：
1998-06-01
期刊：
影响因子：
11.4
通讯作者：
Roth, SY
中科院分区：
文献类型：
--
作者：
Zhang, WZ;Bone, JR;Roth, SY
Gcn 5 p组蛋白乙酰转移酶在体外表现出有限的底物特异性，然而，无论是在体内这种酶的特异性，也不是特定的乙酰化残基的转录或细胞生长的重要性是很好地定义。为了探讨这些问题，我们突变组蛋白H3和H4的N-末端中的特定赖氨酸，并检查这些突变在具有和不具有功能性GCN 5的酵母菌株中的影响。我们发现，在体内，除了体外重组酶识别的那些位点之外，GCN 5直接或间接地需要用于H3和H4中的几个位点的乙酰化。此外，在缺乏GCN 5的情况下，细胞在G（2）/M中积累，表明GCN 5 p功能对正常细胞周期进展很重要。H3中K14的突变作为体外重组Gcn 5 p乙酰化的主要靶点，在gcn 5细胞中赋予强烈的合成生长缺陷，在携带赖氨酸对突变的gcn 5细胞中也观察到协同生长缺陷组蛋白H4中的（K8/K16或K5/K12），引人注目的是，H3中的K14以及H4中的K8和K16同时突变为精氨酸，或者缺失H3或H4 N末端尾部，导致GCN 5细胞死亡。这三个位点突变为谷氨酰胺并不致命。事实上，这种突变的组合在很大程度上绕过了GCN 5通过Ga 14-VP 16进行转录激活的需要，支持组蛋白乙酰化在Gcn 5 p介导的转录调控中的重要作用。我们的数据表明，乙酰化组蛋白H3和H4中的特定赖氨酸提供独特的和重叠的功能，对正常细胞生长很重要，并且组蛋白乙酰化的关键总体水平是细胞活力所必需的。
The Gcn5p histone acetyltransferase exhibits a limited substrate specificity in vitro, However, neither the specificity of this enzyme in vivo nor the importance of particular acetylated residues to transcription or cell growth are well defined. To probe these questions, we mutated specific lysines in the N-termini of histones H3 and H4 and examined the effects of these mutations in yeast strains with and without functional GCN5, We found that in vivo, GCN5 is required either directly or indirectly for the acetylation of several sites in H3 and H4 in addition to those recognized by the recombinant enzyme in vitro. Moreover in the absence of GCN5, cells accumulate in G(2)/M indicating that Gcn5p functions are important for normal cell-cycle progression. Mutation of K14 in H3, which serves as the major target of recombinant Gcn5p acetylation in vitro, confers a strong, synthetic growth defect in gcn5 cells, Synergistic growth defects were also observed in gcn5 cells carrying mutations in lysine pairs (K8/K16 or K5/K12) in histone H4, Strikingly, simultaneous mutation of K14 in H3 and K8 and K16 in H4 to arginine, or deletion of either the H3 or the H4 N-terminal tail, results in the death of gcn5 cells. Mutation of these same three sites to glutamine is not lethal. Indeed, this combination of mutations largely bypasses the need for GCN5 for transcriptional activation by Ga14-VP16, supporting an important role for histone acetylation in Gcn5p-mediated regulation of transcription. Our data indicate that acetylation of particular lysines in histones H3 and H4 serves both unique and overlapping functions important for normal cell growth, and that a critical overall level of histone acetylation is essential for cell viability.