RNA polymerase subunit RPB5 plays a role in transcriptional activation
RNA polymerase subunit RPB5 plays a role in transcriptional activation
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DOI：
10.1073/pnas.95.26.15281
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发表时间：
1998-12-22
影响因子：
11.1
通讯作者：
Woychik, NA
中科院分区：
文献类型：
--
作者：
Miyao, T;Woychik, NA
RPB5(rpb5-9)的突变揭示了该亚单位在转录激活中的作用。RPB5(rpb5-9)是组装成RNA聚合酶I、II和III的基本RNA聚合酶亚基。突变的全细胞提取物在体外转录时，GAL4-VP16的激活作用受到损害。使用可诱导报告质粒的体内实验和Northern分析支持体外数据，并证明RPB5影响某些但不是所有启动子的激活。值得注意的是，这种突变映射到人类RPB5的一个保守区域，其他人认为这一区域在激活过程中发挥了作用。含有这个保守区的嵌合人酵母RPB5现在可以取代其酵母对应物。Rpb5-9注意到的缺陷类似于RPB1-羧基末端结构域(CTD)的截断突变体中看到的缺陷。我们证明RPB5和RPB1-CTD在激活过程中具有重叠的作用，因为双重突变体是合成致命的，并加剧了GAL1/10启动子的激活缺陷。这些研究表明，在RNA聚合酶II中存在多个激活靶点，RPB5和CTD在激活过程中具有相似的作用。
A mutation in RPB5 (rpb5-9), an essential RNA polymerase subunit assembled into RNA polymerases I, II, and III, revealed a role for this subunit in transcriptional activation. Activation by GAL4-VP16 was impaired upon in vitro transcription with mutant whole-cell extracts. In vivo experiments using inducible reporter plasmids and Northern analysis support the in vitro data and demonstrate that RPB5 influences activation at some, but not all, promoters. Remarkably, this mutation maps to a conserved region of human RPB5 implicated by others to play a role in activation. Chimeric human-yeast RPB5 containing this conserved region now can function in place of its yeast counterpart. The defects noted with rpb5-9 are similar to those seen in truncation mutants of the RPB1-carboxyl terminal domain (CTD). We demonstrate that RPB5 and the RPB1-CTD have overlapping roles in activation because the double mutant is synthetically lethal and has exacerbated activation defects at the GAL1/10 promoter. These studies demonstrate that there are multiple activation targets in RNA polymerase II and that RPB5 and the CTD have similar roles in activation.