High-resolution mapping of transcribing RNAPIII by CRAC upon mutation of Sen1 in the G1 phase of the cell cycle [Experiment 3]

Here we report high-resolution analyses of transcribing RNAPIII in either a wild-type (WT) background or a sen1-3 mutant in the G1 phase of the cell cycle. The mutations in Sen1-3 prevent the interaction of Sen1 with both RNAPIII and the replisome, raising the question whether the role of Sen1 in RNAPIII transcription termination could depend on the association of Sen1 with the replisome. Our data show that in the G1 phase of the cell cycle, where the replisome is not assembled, the sen1-3 mutant also exhibits transcription termination defects at RNAPIII-dependent genes, as in asynchronous cells. This result indicates that the role of Sen1 in termination at RNAPIII-dependent genes is independent on the association of Sen1 with the replisome.本研究报道了细胞周期G1期下，野生型（WT）背景或sen1-3突变体背景中，转录中的RNA聚合酶III（RNAPIII）的高分辨率分析结果。Sen1-3突变会阻断Sen1与RNA聚合酶III以及复制体（replisome）的相互作用，由此提出科学问题：Sen1在RNA聚合酶III转录终止中的功能是否依赖于其与复制体的结合。我们的实验数据显示，在复制体尚未组装的细胞周期G1期中，sen1-3突变体与异步培养细胞中一致，同样在RNA聚合酶III依赖型基因上表现出转录终止缺陷。该结果表明，Sen1在RNA聚合酶III依赖型基因的转录终止过程中所发挥的功能，并不依赖于其与复制体的结合。