The NC2 repressor is dispensable in yeast mutated for the Sin4p component of the holoenzyme and plays roles similar to Mot1p in vivo
The NC2 repressor is dispensable in yeast mutated for the Sin4p component of the holoenzyme and plays roles similar to Mot1p in vivo
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DOI：
10.1046/j.1365-2958.2000.01839.x
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发表时间：
2000-04-01
影响因子：
3.6
通讯作者：
Collart, MA
中科院分区：
文献类型：
--
作者：
Lemaire, M;Xie, J;Collart, MA
NC 2（Dr 1/DRAP 1）和Mot 1 p是在酿酒酵母和人类中分离的转录全局阻遏物。NC 2是二聚体组蛋白折叠复合物，其通过与TBP结合并抑制TFIIA和TFIIB来抑制RNA聚合酶II转录。Mot 1 p是一种ATP酶，在ATP水解时去除DNA结合的TBP。在这项工作中，我们研究了核心启动子特异性的NC 2在体内使用的菌株，携带突变的NC 2 β活性。我们表明，NC 2，Mot 1 p一样，是所需的转录的HIS 3和HIS 4 TATA的核心启动子。此外，虽然Mot 1 p和NC 2似乎都没有作为抑制剂的HIS 3基因在葡萄糖中呈指数增长的细胞中发挥作用，我们发现，这两个都是必要的抑制HIS 3 TATA启动子时，细胞通过二次移位。因此，这些因子的活性根据生理条件类似地调节，并且似乎通过它们是否含有典型TATA序列来区分在体内被它们激活或抑制的核心启动子。最后，虽然NC 2是酵母生存力的一个重要因素，但我们在全酶Sin 4p的非必需组分中分离出了一个突变，该突变绕过了对NC 2的要求。
NC2 (Dr1/DRAP1) and Mot1p are global repressors of transcription that have been isolated in both Saccharomyces cerevisiae and humans. NC2 is a dimeric histone-fold complex that represses RNA polymerase II transcription through binding to TBP and inhibition of TFIIA and TFIIB. Mot1p is an ATPase that removes DNA-bound TBP upon ATP hydrolysis. In this work, we studied the core promoter specificity of NC2 in vivo using a strain that carries mutated NC2 beta activity. We show that NC2, like Mot1p, is required for transcription of the HIS3 and HIS4 TATA-less core promoters. Furthermore, whereas neither Mot1p nor NC2 appear to function as repressors of the HIS3 gene in cells growing exponentially in glucose, we find that both are required for repression of the HIS3 TATA promoter when cells go through the diauxic shift. Thus, the activity of these factors is similarly regulated depending upon the physiological conditions, and it appears that core promoters activated or repressed by them in vivo might be distinguishable by whether or not they contain a canonical TATA sequence. Finally, although NC2 is an essential factor for yeast viability, we isolated a mutation in a non-essential component of the holoenzyme, Sin4p, that bypasses the requirement for NC2.