The balance sheet for transcription: an analysis of nuclear RNA metabolism in mammalian cells

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Item Type:	Review
Title:	The balance sheet for transcription: an analysis of nuclear RNA metabolism in mammalian cells
Creators Name:	Jackson, D.A., Pombo, A. and Iborra, F.
Abstract:	The control of RNA synthesis from protein-coding genes is fundamental in determining the various cell types of higher eukaryotes. The activation of these genes is driven by promoter complexes, and RNA synthesis is performed by an enzyme mega-complex-the RNA polymerase II holoenzyme. These two complexes are the fundamental components required to initiate gene expression and generate the primary transcripts that, after processing, yield mRNAs that pass to the cytoplasm where protein synthesis occurs. But although this gene expression pathway has been studied intensively, aspects of RNA metabolism remain difficult to comprehend. In particular, it is unclear why >95% of RNA polymerized by polymerase II remains in the nucleus, where it is recycled. To explain this apparent paradox, this review presents a detailed description of nuclear RNA (nRNA) metabolism in mammalian cells. We evaluate the number of active transcription units, discuss the distribution of polymerases on active genes, and assess the efficiency with which the products mature and pass to the cytoplasm. Differences between the behavior of mRNAs on this productive pathway and primary transcripts that never leave the nucleus lead us to propose that these represent distinct populations. We discuss possible roles for nonproductive RNAs and present a model to describe the metabolism of these RNAs in the nuclei of mammalian cells.-Jackson, D. A., Pombo, A., Iborra, F. The balance sheet for transcription: an analysis of nuclear RNA metabolism in mammalian cells.
Keywords:	Gene Expression, RNA Polymerase, Nascent Transcripts, Transcript Profiles, Nuclear Structure, Animals, Mammals
Source:	FASEB Journal
ISSN:	0892-6638
Publisher:	Federation of American Societies for Experimental Biology
Volume:	14
Number:	2
Page Range:	242-54
Date:	February 2000
Official Publication:	https://doi.org/10.1096/fasebj.14.2.242
PubMed:	View item in PubMed

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