Two isoforms of human RNA polymerase III with specific functions in cell growth and transformation

Item Type:	Article
Title:	Two isoforms of human RNA polymerase III with specific functions in cell growth and transformation
Creators Name:	Haurie, V. and Durrieu-Gaillard, S. and Dumay-Odelot, H. and Da Silva, D. and Rey, C. and Prochazkova, M. and Roeder, R.G. and Besser, D. and Teichmann, M.
Abstract:	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 (RPC32beta) that led to the demonstration of two human Pol III isoforms (Pol IIIalpha and Pol IIIbeta). RPC32beta-containing Pol IIIbeta is ubiquitously expressed and essential for growth of human cells. RPC32alpha-containing Pol IIIalpha 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 RPC32alpha expression impedes anchorage-independent growth of HeLa cells, whereas ectopic expression of RPC32alpha 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.
Keywords:	RPC32alpha, RPC32beta, ES Cells, Differentiation, Transcription
Source:	Proceedings of the National Academy of Sciences of the United States of America
ISSN:	0027-8424
Publisher:	National Academy of Sciences
Volume:	107
Number:	9
Page Range:	4176-4181
Date:	2 March 2010
Official Publication:	https://doi.org/10.1073/pnas.0914980107
PubMed:	View item in PubMed

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