Ahearn J M, Bartolomei M S, West M L, Cisek L J, Corden J L
J Biol Chem. 1987 Aug 5;262(22):10695-705.
The genomic locus (RPII215) encoding the largest subunit of mouse RNA polymerase II has been cloned by low stringency hybridization to a Drosophila RPII215 probe. The mouse gene consists of 28 exons which span 30 kilobases. Analysis of the nucleotide and predicted protein sequences indicates that the protein is comprised of two domains. There is a 1500 residue amino-terminal domain which contains seven regions strikingly similar to those in the beta' subunit of Escherichia coli RNA polymerase, and a carboxyl-terminal domain comprised of 52 repeats of a 7-amino-acid consensus sequence Tyr-Ser-Pro-Thr-Ser-Pro-Ser. Among the seven highly conserved regions are a strongly basic domain consistent with a DNA-binding site and a consensus sequence characteristic of a potential zinc-binding domain. The 5' upstream region contains three tandem sequences similar to binding sites for the transcription factor SP1. Two of the introns in this gene splice at donor GC dinucleotides as opposed to previously described invariant GT sites. The identification of regions which are highly conserved as compared with bacterial and yeast RNA polymerase and other regions which are unique to the mouse protein suggests which domains of RNA polymerase large subunits are involved in aspects of transcription common to both procaryotes and eucaryotes and which are characteristic of transcription in higher organisms.
通过与果蝇RPII215探针进行低严谨度杂交，克隆出了编码小鼠RNA聚合酶II最大亚基的基因组位点（RPII215）。小鼠基因由28个外显子组成，跨度为30千碱基。对核苷酸和预测的蛋白质序列分析表明，该蛋白质由两个结构域组成。有一个1500个残基的氨基末端结构域，其中包含七个与大肠杆菌RNA聚合酶β'亚基中的区域非常相似的区域，以及一个由7个氨基酸共有序列Tyr-Ser-Pro-Thr-Ser-Pro-Ser的52个重复序列组成的羧基末端结构域。在这七个高度保守的区域中，有一个与DNA结合位点一致的强碱性结构域和一个潜在锌结合结构域的共有序列特征。5'上游区域包含三个与转录因子SP1结合位点相似的串联序列。该基因中的两个内含子在供体GC二核苷酸处剪接，而不是先前描述的不变GT位点。与细菌和酵母RNA聚合酶相比高度保守的区域以及小鼠蛋白质特有的其他区域的鉴定，表明了RNA聚合酶大亚基的哪些结构域参与了原核生物和真核生物共有的转录方面，以及哪些是高等生物转录的特征。
