High-resolution mapping of transcribing Pol III by CRAC in the WT and C128 mutants

Here we report high-resolution analyses of transcribing RNA polymerase III (Pol III) in a wild-type (WT) strain and three C128 mutants. C128 is the second largest subunit of Pol III, which is the key subunit to recognize termination signal. Mutating key residues in C128 interferes with transcription termination in vitro and affect yeast viability as well, raising the question that whether these mutations provoke Pol III termination defects in vivo. Here we show that C128 mutants display termination defects at most PolIII-dependent genes, indicating that the most disruptive C128 mutations indeed impair Pol III transcription termination in vivo本研究报道了野生型（WT）菌株与三种C128突变体中，转录状态下RNA聚合酶III（RNA polymerase III）的高分辨率分析结果。C128是RNA聚合酶III的第二大亚基，亦是识别转录终止信号的关键亚基。对C128的关键残基进行突变，不仅会在体外干扰转录终止过程，还会影响酵母的存活力，由此引出关键科学疑问：此类突变是否会在体内引发RNA聚合酶III的终止缺陷？本研究结果显示，C128突变体在绝大多数依赖RNA聚合酶III的基因位点均表现出转录终止缺陷，这表明破坏性最强的C128突变确实会在体内损害RNA聚合酶III的转录终止功能。