Genome-wide analysis of the functions of a conserved surface on the corepressor Tup1
Genome-wide analysis of the functions of a conserved surface on the corepressor Tup1
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DOI：
10.1091/mbc.e05-02-0126
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发表时间：
2005-06-01
影响因子：
3.3
通讯作者：
Johnson, AD
中科院分区：
文献类型：
--
作者：
Green, SR;Johnson, AD
通用转录阻遏蛋白 Tup1 负责调节酿酒酵母中大量不同的基因，并且已在许多后生动物中鉴定出 Tup1 的功能同源物。 Tup1 C 端部分的晶体结构已得到解决，并且当比较真菌和后生动物的 Tup1 同源物序列时，揭示了高度保守的表面。在本文中，我们分析了这个保守表面上的五个点突变。表达微阵列的统计分析表明，突变等位基因在抑制 Tup1 调节基因的不同子集方面存在缺陷。我们能够根据抑制缺陷的严重程度对 TUP1 突变等位基因进行排序，该严重程度通过去抑制基因的数量和去抑制的程度来衡量。对于一类特定的基因，保守表面上的突变破坏了 Tup1 向受抑制启动子的募集。然而，对于大多数被 Tup1 点突变体去抑制的基因来说，Tup1 向受调节启动子的募集基本上不受影响。这些突变影响复合物募集后的抑制机制，并可能代表真菌和后生动物中保守机制的破坏。这项工作表明，Tup1 的进化保守表面与两种不同类型的蛋白质相互作用——序列特异性 DNA 结合蛋白，负责将 Tup1 招募到启动子以及可能在保守抑制机制中发挥作用的组件。
The general transcriptional repressor Tup1 is responsible for the regulation of a large, diverse set of genes in Saccharomyces cerevisiae, and functional homologues of Tup1 have been identified in many metazoans. The crystal structure for the C-terminal portion of Tup1 has been solved and, when sequences of Tup1 homologues from fungi and metazoans were compared, a highly conserved surface was revealed. In this article, we analyze five point mutations that lie on this conserved surface. A statistical analysis of expression microarrays demonstrates that the mutant alleles are deficient in the repression of different subsets of Tup1-regulated genes. We were able to rank the mutant alleles of TUP1 based on the severity of their repression defects measured both by the number of genes derepressed and by the magnitude of that derepression. For one particular class of genes, the mutations on the conserved surface disrupted recruitment of Tup1 to the repressed promoters. However, for the majority of the genes derepressed by the Tup1 point mutants, recruitment of Tup1 to the regulated promoters is largely unaffected. These mutations affect the mechanism of repression subsequent to recruitment of the complex and likely represent a disruption of a mechanism that is conserved in fungi and metazoans. This work demonstrates that the evolutionarily conserved surface of Tup1 interacts with two separate types of proteins-sequence-specific DNA-binding proteins responsible for recruiting Tup1 to promoters as well as components that are likely to function in a conserved repression mechanism.