GENETIC-EVIDENCE FOR AN INTERACTION BETWEEN SIR3 AND HISTONE-H4 IN THE REPRESSION OF THE SILENT MATING LOCI IN SACCHAROMYCES-CEREVISIAE
GENETIC-EVIDENCE FOR AN INTERACTION BETWEEN SIR3 AND HISTONE-H4 IN THE REPRESSION OF THE SILENT MATING LOCI IN SACCHAROMYCES-CEREVISIAE
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DOI：
10.1073/pnas.87.16.6286
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发表时间：
1990-08-01
影响因子：
11.1
通讯作者：
GRUNSTEIN, M
中科院分区：
文献类型：
--
作者：
JOHNSON, LM;KAYNE, PS;GRUNSTEIN, M
沉默交配位点（HML.alpha）的转录抑制。和HMRa)对酿酒酵母的交配能力至关重要。这种沉默已知需要至少5种蛋白（SIR1、sirr2、SIR3、SIR4和组蛋白H4），并伴随着染色质结构的改变。我们在这里展示了组蛋白H4的四个位置（n末端残基16,17,18和19）对沉默至关重要。HML.alpha。当这些位置被碱性氨基酸占据时，HMRa被有效抑制，而当这些位置被甘氨酸取代时，HMRa被抑制。这些结果表明Lys-16的乙酰化会导致沉默交配位点的抑制。后H4突变的三个强外基因抑制子被分离出来并确定位于SIR3中。这些抑制因子在表达野生型H4或含有单氨基酸取代的H4的细胞中具有很高的交配效率。他们不允许在含有H4 n末端缺失的菌株中进行有效交配。这些结果表明SIR3突变不会绕过对H4 N末端的要求，而是允许在不理想的H4 N末端存在时进行抑制。这提供了一种SIR蛋白和染色质成分之间的联系。
Repression of transcription from the silent mating loci (HML.alpha. and HMRa) is essential for mating ability in Saccharomyces cerevisiae. This silencing is known to require at least five proteins (SIR1, SIR2, SIR3, SIR4, and histone H4) and is accompanied by a change in chromatin structure. We show here that four positions of histone H4 (N-terminal residues 16, 17, 18, and 19) are crucial to silencing. HML.alpha. and HMRa are efficiently repressed when these positions are occupied by basic amino acids but are derepressed when substituted with glycine. These results suggest that acetylation of Lys-16 would lead to derepression of the silent mating loci. Three strong extragenic suppressors of the latter H4 mutations were isolated and determined to be located in SIR3. These suppressors allow high mating efficiencies in cells expressing either wild-type H4 or H4 containing single amino acid substitutions. They did not allow efficient mating in a strain that contained an H4 N-terminal deletion. These results indicate that the SIR3 mutations do not bypass the requirement for the H4 N terminus but, rather, allow repression in the presence of a less than optimal H4 N terminus. This provides a link between one of the SIR proteins and a component of chromatin.