A novel type of silencing factor, Clr2, is necessary for transcriptional silencing at various chromosomal locations in the fission yeast Schizosaccharomyces pombe
A novel type of silencing factor, Clr2, is necessary for transcriptional silencing at various chromosomal locations in the fission yeast Schizosaccharomyces pombe
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DOI：
10.1093/nar/gkh780
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发表时间：
2004-01-01
影响因子：
14.9
通讯作者：
Thon, G
中科院分区：
文献类型：
--
作者：
Bjerling, P;Ekwall, K;Thon, G
裂殖酵母裂殖酵母的交配型区域包括三个位点：mat 1、mat 2-P和mat 3-M。mat 1被表达并确定细胞的交配类型。mat 2-P和mat 3-M是位于17 kb异染色质区的两个储存盒，具有与哺乳动物异染色质相同的特征。在筛选沉默mat 2-P-mat 3-M区所必需的因子中获得swi 6（+）、clr 1（+）、clr 2（+）、clr 3（+）、clr 4（+）和clr 6（+）基因中的突变。swi 6（+）编码染色体结构域蛋白、clr 3（+）和clr 6（+）组蛋白脱乙酰基酶，以及clr 4（+）组蛋白甲基转移酶。在这里，我们描述clr 2（+）的克隆和表征。clr 2（+）基因编码一个62 kDa的蛋白，没有明显的序列同源物。clr 2（+）的缺失不仅影响交配型区域的转录抑制，而且影响着丝粒沉默和插入rDNA重复序列中的PolII转录基因的沉默。使用染色质免疫沉淀，我们表明，Clr 2是必要的组蛋白hypoacetylation在交配型区域，这表明Clr 2的行为上游组蛋白去乙酰化酶，以促进转录沉默。
The mating-type region of the fission yeast Schizosaccharomyces pombe comprises three loci: mat1, mat2-P and mat3-M. mat1 is expressed and determines the mating type of the cell. mat2-P and mat3-M are two storage cassettes located in a 17 kb heterochromatic region with features identical to those of mammalian heterochromatin. Mutations in the swi6(+), clr1(+), clr2(+), clr3(+), clr4(+) and clr6(+) genes were obtained in screens for factors necessary for silencing the mat2-P-mat3-M region. swi6(+) encodes a chromodomain protein, clr3(+) and clr6(+) histone deacetylases, and clr4(+) a histone methyltransferase. Here, we describe the cloning and characterization of clr2(+). The clr2(+) gene encodes a 62 kDa protein with no obvious sequence homologs. Deletion of clr2(+) not only affects transcriptional repression in the mating-type region, but also centromeric silencing and silencing of a PolII-transcribed gene inserted in the rDNA repeats. Using chromatin immunoprecipitation, we show that Clr2 is necessary for histone hypoacetylation in the mating-type region, suggesting that Clr2 acts upstream of histone deacetylases to promote transcriptional silencing.