Tyrosine-1 of RNA polymerase II CTD controls global termination of gene transcription in mammals

The aim of the project was to analyse the functional role of Tyrosine-1 of mammalian RNA polymerase II CTD in the regulation of transcription-coupled processes. We studied mammalian CTD mutants to analyze the function of tyrosine1 residues. Mutation of 3/4 of the tyrosine residues in a mutant YFFF resulted in a massive read-through transcription phenotype. Read-through was observed for 3’ processed and polyadenylated RNAs. The YFFF mutant shows a loss of interaction with the Mediator and Integrator complexes in MS analysis.

本项目旨在解析哺乳动物RNA聚合酶II（RNA polymerase II）羧基末端结构域（C-terminal domain, CTD）的酪氨酸-1位点在转录偶联过程调控中的功能作用。我们通过构建哺乳动物CTD突变体，对酪氨酸1残基的功能开展分析。其中，将3/4的酪氨酸残基突变为苯丙氨酸的YFFF突变体，呈现出显著的通读转录（read-through transcription）表型。实验观察到，经3'端加工及多聚腺苷酸化修饰的RNA均存在通读转录现象。质谱（mass spectrometry, MS）分析结果显示，YFFF突变体丧失了与中介体（Mediator）复合物及整合器（Integrator）复合物的相互结合能力。