Epigenetic effects on yeast transcription caused by mutations in an actin-related protein present in the nucleus
Epigenetic effects on yeast transcription caused by mutations in an actin-related protein present in the nucleus
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DOI：
10.1101/gad.10.5.604
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发表时间：
1996-03-01
影响因子：
10.5
通讯作者：
Stillman, DJ
中科院分区：
文献类型：
--
作者：
Jiang, YW;Stillman, DJ
当Ty 1转座子的δ元件插入酵母HIS 4启动子（his 4 -912 δ）改变转录起始位点时，可导致基因失活。先前的工作已经确定了通过将转录起始位点恢复到天然位置来抑制这种转录缺陷的突变，并且这些突变与转录调控和染色质结构有关。我们表明，在一个sin 4突变体，这种抑制是不完全的渗透，这样，遗传相同的酵母细胞（sin 4 his 4 -912 δ）显示两种不同的表型状态，他（+）或他（-）。为了研究这种类型的基因表达的潜在表观遗传控制，我们构建了一种在his 4 -912 delta启动子控制下具有ADE 2表达的菌株，因为菌落颜色为ADE 2表达提供了方便的测定。我们分离了ACT 3基因中的突变，这些突变显示ADE 2报告基因的多样化表达。act 3 his 4 delta-ADE 2菌落显示白色和红色扇区，表明在单个菌落中可能存在两种不同的表型。这两种表型状态可以在克隆生长过程中遗传，但是可逆的。从红色或白色的单个菌落中分离的RNA的分析表明，启动子的状态，如开或关，是遗传的，并负责殖民地的颜色。act 3突变也影响HIS 4和LYS 2基因的表达;因此，Act 3 p不是δ元件特异性转录调节因子。免疫荧光显微镜实验表明，Act 3 p蛋白存在于细胞核中。Act 3 p与肌动蛋白具有明显的同源性，并讨论了肌动蛋白相关蛋白在转录中的可能作用。
Gene inactivation can result when a delta element of the Ty1 transposon inserted into the yeast HIS4 promoter (his4-912 delta) alters the transcription initiation site. Previous work has identified mutations that suppress this transcriptional defect by restoring the transcription start site to the native position, and these mutations have been implicated in transcriptional regulation and chromatin structure. We show that in a sin4 mutant such suppression is incompletely penetrant, such that genetically identical yeast cells (sin4 his4-912 delta) show either of two distinct phenotypic states, His(+) or His(-). To study this type of potential epigenetic control of gene expression, we constructed a strain with ADE2 expression under the control of the his4-912 delta promoter, as colony color provides a convenient assay for ADE2 expression. We isolated mutations in the ACT3 gene that show variegated expression of this ADE2 reporter. The act3 his4 delta-ADE2 colonies display both white and red sectors, showing that the two different phenotypes are possible in a single colony. The two phenotypic states can be inherited during clonal growth, yet are reversible. Analysis of RNA isolated from individual colonies of either red or white color demonstrates that it is the state of the promoter, as either On or Off, that is inherited and is responsible for the colony color. An act3 mutation also affects expression of the HIS4 and LYS2 genes; thus, Act3p is not a delta element-specific transcriptional regulator. Immunofluorescence microscopy experiments demonstrate that the Act3p protein is present in the nucleus. Act3p shows clear homology to actin, and possible roles for an actin-related protein in transcription are discussed.