Andrau Jean-Christophe, Van Oevelen Chris J C, Van Teeffelen Hetty A A M, Weil P Anthony, Holstege Frank C P, Timmers H Th Marc
Laboratory for Physiological Chemistry and Department of Medical Genetics, UMC Utrecht, PO Box 85060, 3508 AB Utrecht, The Netherlands.
EMBO J. 2002 Oct 1;21(19):5173-83. doi: 10.1093/emboj/cdf485.
Recruitment of TATA-binding protein (TBP) is central to activation of transcription by RNA polymerase II (pol II). This depends upon co-activator proteins including TBP-associated factors (TAFs). Yeast Mot1p was identified as a general transcriptional repressor in genetic screens and is also found associated with TBP. To obtain insight into Mot1p function in vivo, we determined the mRNA expression profile of the mot1-1 temperature-sensitive (Ts) strain. Unexpectedly, this indicated that Mot1p mostly plays a positive role for transcription. For one potential activation target, HXT2, we analyzed promoter recruitment of Mot1p, TBP, Taf1p (Taf130p) and pol II by chromatin immunoprecipitation assays. Whereas TBP becomes stably associated upon activation of the HXT2 and HXT4 promoters, Mot1p showed only a transient association. TBP recruitment was compromised in two different mot1 mutant strains, but was only moderately affected in a taf1 Ts strain. Together, our data indicate that Mot1p can assist in recruitment of TBP on promoters during gene activation in vivo.
TATA结合蛋白（TBP）的募集对于RNA聚合酶II（pol II）激活转录至关重要。这依赖于包括TBP相关因子（TAFs）在内的共激活蛋白。酵母Mot1p在遗传筛选中被鉴定为一种通用转录抑制因子，并且也被发现与TBP相关。为了深入了解Mot1p在体内的功能，我们确定了mot1-1温度敏感（Ts）菌株的mRNA表达谱。出乎意料的是，这表明Mot1p在转录中大多发挥积极作用。对于一个潜在的激活靶点HXT2，我们通过染色质免疫沉淀试验分析了Mot1p、TBP、Taf1p（Taf130p）和pol II在启动子上的募集情况。当HXT2和HXT4启动子激活时，TBP会稳定结合，而Mot1p仅显示短暂结合。在两种不同的mot1突变菌株中，TBP的募集受到损害，但在taf1 Ts菌株中仅受到中度影响。总之，我们的数据表明Mot1p在体内基因激活过程中可协助TBP在启动子上的募集。
