Rpb7 subunit of RNA polymerase II interacts with an RNA-binding protein involved in processing of transcripts
Rpb7 subunit of RNA polymerase II interacts with an RNA-binding protein involved in processing of transcripts
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DOI：
10.1093/nar/gkg688
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发表时间：
2003-08-15
影响因子：
14.9
通讯作者：
Ishihama, A
中科院分区：
文献类型：
--
作者：
Mitsuzawa, H;Kanda, E;Ishihama, A
Rpb 4-Rpb 7是RNA聚合酶II（pol II）的可解离亚复合物，是转录起始所必需的。为了了解Rpb 7在转录起始或转录中的其他过程中的作用，我们进行了双杂交筛选与裂殖酵母裂殖酵母的Rpb 7相互作用的蛋白质。筛选鉴定了酿酒酵母Nrd 1的粟酒裂殖酵母同源物，Nrd 1是一种RNA结合蛋白，参与由pol II转录的小核仁和小核RNA的3'端形成。粟酒裂殖酵母的蛋白质，命名为Seb 1的七个结合，是细胞活力所必需的，并在体外直接结合到Rpb 7。酿酒酵母Rpb 7也与Nrd 1相互作用，表明这种相互作用在进化中是保守的。发现粟酒裂殖酵母Rpb 7的Glu 166和/或Asp 167（靠近172个氨基酸的蛋白质的C-末端的残基）对于其与Seb 1的相互作用是重要的。我们的研究结果表明，Rpb 7的功能可能是锚加工因子的pol II装置，从而耦合RNA加工转录。Rpb 7的作用是一致的，它的位置在聚合酶II复合物确定最近的结构研究。
Rpb4-Rpb7, a dissociable subcomplex of RNA polymerase II (pol II), is required for transcription initiation. To understand the role of Rpb7 in transcription initiation or other processes in transcription, we carried out a two-hybrid screen for proteins that interact with Rpb7 of the fission yeast Schizosaccharomyces pombe. The screen identified the S.pombe homolog of the Saccharomyces cerevisiae Nrd1, an RNA-binding protein implicated in 3' end formation of small nucleolar and small nuclear RNAs transcribed by pol II. The S.pombe protein, named Seb1 for seven binding, was essential for cell viability, and bound directly to Rpb7 in vitro. Saccharomyces cerevisiae Rpb7 also interacted with Nrd1, indicating that the interaction is conserved in evolution. Glu166 and/or Asp167 of S.pombe Rpb7, residues near the C-terminus of the 172 amino acid protein, were found to be important for its interaction with Seb1. Our results suggest that Rpb7 may function to anchor a processing factor to the pol II apparatus, thereby coupling RNA processing to transcription. The role for Rpb7 is consistent with its location in the pol II complex determined by recent structural studies.