{"title":"Transcriptional repressor Gal80 recruits corepressor complex Cyc8-Tup1 to structural genes of the Saccharomyces cerevisiae GAL regulon.","authors":"Julia Lettow, Rasha Aref, Hans-Joachim Schüller","doi":"10.1007/s00294-021-01215-x","DOIUrl":null,"url":null,"abstract":"<p><p>Under non-inducing conditions (absence of galactose), yeast structural genes of the GAL regulon are repressed by Gal80, preventing interaction of Gal4 bound to UAS<sub>GAL</sub> promoter motifs with general factors of the transcriptional machinery. In this work, we show that Gal80 is also able to interact with histone deacetylase-recruiting corepressor proteins Cyc8 and Tup1, indicating an additional mechanism of gene repression. This is supported by our demonstration that a lexA-Gal80 fusion efficiently mediates repression of a reporter gene with an upstream lexA operator sequence. Corepressor interaction and in vivo gene repression could be mapped to a Gal80 minimal domain of 65 amino acids (aa 81-145). Site-directed mutagenesis of selected residues within this domain showed that a cluster of aromatic-hydrophobic amino acids (YLFV, aa 118-121) is important, although not solely responsible, for gene repression. Using chromatin immunoprecipitation, Cyc8 and Tup1 were shown to be present at the GAL1 promoter in a wild-type strain but not in a gal80 mutant strain under non-inducing (derepressing) growth conditions. Expression of a GAL1-lacZ fusion was elevated in a tup1 mutant (but not in a cyc8 mutant) grown in derepressing medium, indicating that Tup1 may be mainly responsible for this second mechanism of Gal80-dependent gene repression.</p>","PeriodicalId":10918,"journal":{"name":"Current Genetics","volume":null,"pages":null},"PeriodicalIF":1.8000,"publicationDate":"2022-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8801411/pdf/","citationCount":"5","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Current Genetics","FirstCategoryId":"99","ListUrlMain":"https://doi.org/10.1007/s00294-021-01215-x","RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"2021/10/7 0:00:00","PubModel":"Epub","JCR":"Q3","JCRName":"GENETICS & HEREDITY","Score":null,"Total":0}
引用次数: 5
Abstract
Under non-inducing conditions (absence of galactose), yeast structural genes of the GAL regulon are repressed by Gal80, preventing interaction of Gal4 bound to UASGAL promoter motifs with general factors of the transcriptional machinery. In this work, we show that Gal80 is also able to interact with histone deacetylase-recruiting corepressor proteins Cyc8 and Tup1, indicating an additional mechanism of gene repression. This is supported by our demonstration that a lexA-Gal80 fusion efficiently mediates repression of a reporter gene with an upstream lexA operator sequence. Corepressor interaction and in vivo gene repression could be mapped to a Gal80 minimal domain of 65 amino acids (aa 81-145). Site-directed mutagenesis of selected residues within this domain showed that a cluster of aromatic-hydrophobic amino acids (YLFV, aa 118-121) is important, although not solely responsible, for gene repression. Using chromatin immunoprecipitation, Cyc8 and Tup1 were shown to be present at the GAL1 promoter in a wild-type strain but not in a gal80 mutant strain under non-inducing (derepressing) growth conditions. Expression of a GAL1-lacZ fusion was elevated in a tup1 mutant (but not in a cyc8 mutant) grown in derepressing medium, indicating that Tup1 may be mainly responsible for this second mechanism of Gal80-dependent gene repression.
在非诱导条件下(缺乏半乳糖),酵母GAL调控的结构基因被Gal80抑制,阻止了与UASGAL启动子基序结合的Gal4与转录机制的一般因子的相互作用。在这项工作中,我们发现Gal80也能够与组蛋白去乙酰酶募集共抑制蛋白Cyc8和Tup1相互作用,这表明了基因抑制的另一种机制。我们证明,lexA- gal80融合有效地介导了上游lexA操作符序列对报告基因的抑制,这一点得到了支持。协同抑制因子相互作用和体内基因抑制可以定位到65个氨基酸的Gal80最小结构域(aa 81-145)。该结构域内选定残基的定点诱变表明,一簇芳香疏水氨基酸(YLFV, aa 118-121)虽然不是基因抑制的唯一原因,但也很重要。利用染色质免疫沉淀,Cyc8和Tup1在野生型菌株中存在于GAL1启动子上,而在非诱导(去抑制)生长条件下,在gal80突变菌株中不存在。在去抑制培养基中生长的tup1突变体(而不是cyc8突变体)中,GAL1-lacZ融合表达升高,表明tup1可能主要负责gal80依赖性基因抑制的第二种机制。
期刊介绍:
Current Genetics publishes genetic, genomic, molecular and systems-level analysis of eukaryotic and prokaryotic microorganisms and cell organelles. All articles are peer-reviewed. The journal welcomes submissions employing any type of research approach, be it analytical (aiming at a better understanding), applied (aiming at practical applications), synthetic or theoretical.
Current Genetics no longer accepts manuscripts describing the genome sequence of mitochondria/chloroplast of a small number of species. Manuscripts covering sequence comparisons and analyses that include a large number of species will still be considered.