Subcellular localization shapes the fate of RNA polymerase III
Kai Tian,
Rui Wang,
Jie Huang,
Hui Wang,
Xiong Ji
Affiliations
Kai Tian
Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, School of Life Sciences, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China
Rui Wang
Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, School of Life Sciences, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China
Jie Huang
Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, School of Life Sciences, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China
Hui Wang
Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, School of Life Sciences, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China
Xiong Ji
Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, School of Life Sciences, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China; Corresponding author
Summary: RNA polymerase III (Pol III) plays a vital role in transcription and as a viral-DNA sensor, but how it is assembled and distributed within cells remains poorly understood. Here, we show that Pol III is assembled with chaperones in the cytoplasm and forms transcription-dependent protein clusters upon transport into the nucleus. The largest subunit (RPC1) depletion through an auxin-inducible degron leads to rapid degradation and disassembly of Pol III complex in the nucleus and cytoplasm, respectively. This generates a pool of partially assembled Pol III intermediates, which can be rapidly mobilized into the nucleus upon the restoration of RPC1. Our study highlights the critical role of subcellular localization in determining Pol III’s fate and provides insight into the dynamic regulation of nuclear Pol III levels and the origin of cytoplasmic Pol III complexes involved in mediating viral immunity.
