AMINO-ACID SUBSTITUTIONS IN THE STRUCTURED DOMAINS OF HISTONES H3 AND H4 PARTIALLY RELIEVE THE REQUIREMENT OF THE YEAST SWI/SNF COMPLEX FOR TRANSCRIPTION
AMINO-ACID SUBSTITUTIONS IN THE STRUCTURED DOMAINS OF HISTONES H3 AND H4 PARTIALLY RELIEVE THE REQUIREMENT OF THE YEAST SWI/SNF COMPLEX FOR TRANSCRIPTION
复制标题
DOI：
10.1101/gad.9.22.2770
复制
发表时间：
1995-11-15
影响因子：
10.5
通讯作者：
HERSKOWITZ, I
中科院分区：
文献类型：
--
作者：
KRUGER, W;PETERSON, CL;HERSKOWITZ, I
许多酵母基因的转录需要SWI/SNF调控复合体。先前的研究表明，在swi和snf突变体中，HO基因转录的减少可以通过SIN1和SIN2基因的突变部分缓解。在这里，我们发现SIN2与HHT1是相同的，HHT1是编码组蛋白H3的两个基因之一，任何一个基因的突变都可以导致Sin（-）表型。这些突变部分优势于野生型，并导致组蛋白H3结构域中三个保守位置的氨基酸取代。我们还发现了部分显性的sin突变，影响组蛋白H4的组蛋白折叠域的两个保守位置。三个sin突变影响与DNA相互作用的表面残基，并可能降低DNA对组蛋白八聚体的亲和力。两个sin突变影响组蛋白八聚体（H2A-H2B）二聚体和（H3-H4）(2)四聚体亚基之间的界面或附近的残基，并可能影响核小体的稳定性或构象。突变影响组蛋白八聚体结构以减轻对SWI和SNF产物的需求的能力支持了SWI/SNF复合物通过改变染色质结构刺激转录的建议，并可以解释除酵母外的真核生物中SWI和SNF蛋白的明显保护。
Transcription of many yeast genes requires the SWI/SNF regulatory complex. Prior studies show that reduced transcription of the HO gene in swi and snf mutants is partially relieved by mutations in the SIN1 and SIN2 genes. Here we show that SIN2 is identical to HHT1, one of the two genes coding for histone H3, and that mutations in either can result in a Sin(-) phenotype. These mutations are partially dominant to wild type and cause amino acid substitutions in three conserved positions in the structured domain of histone H3. We have also identified partially dominant sin mutations that affect two conserved positions in the histone-fold domain of histone H4. Three sin mutations affect surface residues proposed to interact with DNA and may reduce affinity of DNA for the histone octamer. Two sin mutations affect residues at or near interfaces between (H2A-H2B) dimer and (H3-H4)(2) tetramer subunits of the histone octamer and may affect nucleosome stability or conformation. The ability of mutations affecting the structure of the histone octamer to relieve the need for SWI and SNF products supports the proposal that the SWI/SNF complex stimulates transcription by altering chromatin structure and can account for the apparent conservation of SWI and SNF proteins in eukaryotes other than yeast.