Geisberg J V, Holstege F C, Young R A, Struhl K
Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115, USA.
Mol Cell Biol. 2001 Apr;21(8):2736-42. doi: 10.1128/MCB.21.8.2736-2742.2001.
NC2 (Dr1-Drap1 or Bur6-Ydr1) has been characterized in vitro as a general negative regulator of RNA polymerase II (Pol II) transcription that interacts with TATA-binding protein (TBP) and inhibits its function. Here, we show that NC2 associates with promoters in vivo in a manner that correlates with transcriptional activity and with occupancy by basal transcription factors. NC2 rapidly associates with promoters in response to transcriptional activation, and it remains associated under conditions in which transcription is blocked after assembly of the Pol II preinitiation complex. NC2 positively and negatively affects approximately 17% of Saccharomyces cerevisiae genes in a pattern that resembles the response to general environmental stress. Relative to TBP, NC2 occupancy is high at promoters where NC2 is positively required for normal levels of transcription. Thus, NC2 is associated with the Pol II preinitiation complex, and it can play a direct and positive role at certain promoters in vivo.
NC2（Dr1-Drap1或Bur6-Ydr1）在体外已被表征为RNA聚合酶II（Pol II）转录的一般负调控因子，它与TATA结合蛋白（TBP）相互作用并抑制其功能。在此，我们表明NC2在体内与启动子结合，其方式与转录活性以及基础转录因子的占据情况相关。响应转录激活，NC2迅速与启动子结合，并且在Pol II预起始复合物组装后转录受阻的条件下仍保持结合。NC2以类似于对一般环境应激反应的模式对约17%的酿酒酵母基因产生正向和负向影响。相对于TBP，在正常转录水平正向需要NC2的启动子处，NC2的占据率较高。因此，NC2与Pol II预起始复合物相关联，并且它可以在体内某些启动子处发挥直接的正向作用。
