通知：暂时取消！2024.4.19 俞洋研究员（广州医科大学附属广州市妇女儿童医疗中心/中国科学院生物物理研究所）学术报告

报告题目：Eukaryotic CRISPR: a piRNA-guided “innate immune” system in genome defence
报告人：俞   洋 研究员 
主持人：任艾明 研究员
时   间：2024年4月19日（周五）下午2点
地   点：纳米楼457报告厅
报告人简介：

       俞洋研究员，博导，现就职于广州医科大学附属广州市妇女儿童医疗中心，并为中国科学院生物物理研究所客座教授。2002年毕业于武汉大学病毒学专业，2007年获得美国凯斯西储大学博士学位。2010-2016在美国冷泉港实验室博士后。2016-2022年受聘于中国科学院生物物理研究所任研究员。

       非编码RNA在胚胎早期发育和生殖过程中调控表观遗传的功能和分子机制。迄今为止以通讯或第一作者在Nature Cell Biology、Science、Cell、RNA和GPB等杂志发表论文，文章总引用次数超过500。近年来获得过“青年千人”、“国家自然科学基金面上项目”、“基金委重大研究计划培育/集成项目”、“科技部重点研发”、“中科院先导B”等科研基金的资助。

讲座摘要：

The repression of transposons by the Piwi-interacting RNA (piRNA) pathway is essential to protect animal germ cells. In Drosophila ovaries, Panoramix (Panx) enforces transcriptional silencing by binding to the target-engaged Piwi-piRNA complex, although the precise mechanisms by which this occur remain elusive. Previously, we identified a Pandas (Panoramix-dNxf2 dependent TAP silencing) complex, which counteract the canonical RNA exporting machinery (TAP/p15) and restrict transposons within nucleus. Interestingly, Chen Hong and colleagues recently showed that TAP/Nxf1 is required for efficient RNA polymerase II (Pol II) elongation, suggesting that Pandas complex may directly block Pol II elongation. In fact, we identified Pcf11 as a key factor required Panx-mediated silencing.

Transcription termination of RNA polymerase II (Pol II) is a fundamental process required for gene expression. The large subunit of Pol II contains an intrinsically disordered C-terminal domain that regulates transcriptional initiation and elongation via phase separation. However, it is not clear if pol II termination is regulated by phase separation. Here, we show that a key termination factor, Pcf11, can form phase-separated condensates that are induced by direct binding to the C-terminal domain of Pol II. Most importantly, the region of Pcf11 that induces condensate formation is essential for Pcf11-mediated Pol II termination. In addition, Pcf11 form condensates with phosphorylated C-terminal domain, encompassing SR proteins. Taken together, we propose that Pcf11 facilitate transcriptional termination by driving phase-separated elongating Pol II into the termination condensates.