期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2010
卷号：107
期号：9
页码：4176-4181
DOI：10.1073/pnas.0914980107
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Transcription in eukaryotic nuclei is carried out by DNA-dependent RNA polymerases I, II, and III. Human RNA polymerase III (Pol III) transcribes small untranslated RNAs that include tRNAs, 5S RNA, U6 RNA, and some microRNAs. Increased Pol III transcription has been reported to accompany or cause cell transformation. Here we describe a Pol III subunit (RPC32{beta}) that led to the demonstration of two human Pol III isoforms (Pol III and Pol III{beta}). RPC32{beta}-containing Pol III{beta} is ubiquitously expressed and essential for growth of human cells. RPC32-containing Pol III is dispensable for cell survival, with expression being restricted to undifferentiated ES cells and to tumor cells. In this regard, and most importantly, suppression of RPC32 expression impedes anchorage-independent growth of HeLa cells, whereas ectopic expression of RPC32 in IMR90 fibroblasts enhances cell transformation and dramatically changes the expression of several tumor-related mRNAs and that of a subset of Pol III RNAs. These results identify a human Pol III isoform and isoform-specific functions in the regulation of cell growth and transformation.
关键词：RPC32α ; RPC32β ; ES cells ; differentiation ; transcription
