The Dr1/DRAP1 heterodimer is a global repressor of transcription in vivo
The Dr1/DRAP1 heterodimer is a global repressor of transcription in vivo
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DOI：
10.1073/pnas.94.3.820
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发表时间：
1997-02-04
影响因子：
11.1
通讯作者：
Reinberg, D
中科院分区：
文献类型：
--
作者：
Kim, S;Na, JG;Reinberg, D
在体外被广泛研究的一个普遍的抑制物是人DR1/DRAP1异二聚体复合体。为了阐明DR1和DRAP1在体内的功能，我们鉴定了酿酒酵母DR1/DRAP1阻遏蛋白复合体。阻遏复合体由两个必需基因编码，分别命名为YDR1和BUR6。通过表达人类基因，可以克服与酵母基因缺失相关的无活性。然而，只有当人DR1共表达时，人的辅阻遏子DRAP1才能在酵母中发挥作用。YDr1/Bur6复合体在重组的RNA聚合酶II转录系统中抑制体外转录。提高TATA元件结合蛋白(TBP)的浓度可以克服转录抑制。与体外结果一致的是，YDR1在体内的过表达导致了mRNA积累的减少。此外，YDR1的过度表达损害了细胞的生长，这种影响可以通过过度表达TBP来挽救。与我们之前的体外研究一致，我们发现在体内过表达DR1也影响RNA聚合酶III转录本的积累，但不影响RNA聚合酶I转录本的积累。我们的结果表明，Dr1在体内发挥转录抑制因子的作用，而且直接针对TBP，一种全球转录调节因子。
A general repressor extensively studied in vitro is the human Dr1/DRAP1 heterodimeric complex. To elucidate the function of Dr1 and DRAP1 in vivo, the yeast Saccharomyces cerevisiae Dr1/DRAP1 repressor complex was identified. The repressor complex is encoded by two essential genes, designated YDR1 and BUR6. The inviability associated with deletion of the yeast genes can be overcome by expressing the human genes. However, the human corepressor DRAP1 functions in yeast only when human Dr1 is coexpressed. The yDr1/Bur6 complex represses transcription in vitro in a reconstituted RNA polymerase II transcription system. Repression of transcription could be overcome by increasing the concentration of TATA-element binding protein (TBP). Consistent with the in vitro results, overexpression of YDR1 in vivo resulted in decreased mRNA accumulation. Furthermore, YDR1 overexpression impaired cell growth, an effect that could be rescued by overexpression of TBP. In agreement with our previous studies in vitro, we found that overexpression of Dr1 in vivo also affected the accumulation of RNA polymerase III transcripts, but not of RNA polymerase I transcripts. Our results demonstrate that Dr1functions as a repressor of transcription in vivo and, moreover, directly targets TBP, a global regulator of transcription.