Yuryev A, Patturajan M, Litingtung Y, Joshi R V, Gentile C, Gebara M, Corden J L
Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205-2185, USA.
Proc Natl Acad Sci U S A. 1996 Jul 9;93(14):6975-80. doi: 10.1073/pnas.93.14.6975.
Although transcription and pre-mRNA processing are colocalized in eukaryotic nuclei, molecules linking these processes have not previously been described. We have identified four novel rat proteins by their ability to interact with the repetitive C-terminal domain (CTD) of RNA polymerase II in a yeast two-hybrid assay. A yeast homolog of one of the rat proteins has also been shown to interact with the CTD. These CTD-binding proteins are all similar to the SR (serine/arginine-rich) family of proteins that have been shown to be involved in constitutive and regulated splicing. In addition to alternating Ser-Arg domains, these proteins each contain discrete N-terminal or C-terminal CTD-binding domains. We have identified SR-related proteins in a complex that can be immunoprecipitated from nuclear extracts with antibodies directed against RNA polymerase II. In addition, in vitro splicing is inhibited either by an antibody directed against the CTD or by wild-type but not mutant CTD peptides. Thus, these results suggest that the CTD and a set of CTD-binding proteins may act to physically and functionally link transcription and pre-mRNA processing.
虽然转录和前体mRNA加工在真核细胞核中是共定位的，但此前尚未描述过连接这些过程的分子。我们通过在酵母双杂交试验中与RNA聚合酶II的重复C末端结构域（CTD）相互作用的能力，鉴定出了四种新的大鼠蛋白。其中一种大鼠蛋白的酵母同源物也已被证明能与CTD相互作用。这些CTD结合蛋白都与SR（富含丝氨酸/精氨酸）蛋白家族相似，该家族蛋白已被证明参与组成型和调控型剪接。除了交替的丝氨酸-精氨酸结构域外，这些蛋白各自还含有离散的N末端或C末端CTD结合结构域。我们在一个复合物中鉴定出了与SR相关的蛋白，该复合物可用针对RNA聚合酶II的抗体从核提取物中免疫沉淀出来。此外，体外剪接可被针对CTD的抗体或野生型而非突变型CTD肽抑制。因此，这些结果表明CTD和一组CTD结合蛋白可能在物理和功能上连接转录和前体mRNA加工。
