Cotranscriptional spliceosome assembly dynamics and the role of U1 snRNA:5'ss base pairing in yeast

Item Type:	Article
Title:	Cotranscriptional spliceosome assembly dynamics and the role of U1 snRNA:5'ss base pairing in yeast
Creators Name:	Lacadie, S.A. and Rosbash, M.
Abstract:	To investigate the mechanism of spliceosome assembly in vivo, we performed chromatin immunoprecipitation (ChIP) analysis of U1, U2, and U5 small nuclear ribonucleoprotein particles (snRNPs) to intron-containing yeast (S. cerevisiae) genes. The snRNPs display patterns that indicate a cotranscriptional assembly model: U1 first, then U2, and the U4/U6*U5 tri-snRNP followed by U1 destabilization. cis-splicing mutations also support a role of U2 and/or the tri-snRNP in U1 destabilization. Moreover, they indicate that splicing efficiency has a major impact on cotranscriptional snRNP recruitment and suggest that cotranscriptional recruitment of U2 or the tri-snRNP is required to commit the pre-mRNA to splicing. Branchpoint (BP) mutations had a major effect on the U1 pattern, whereas 5' splice site (5'ss) mutations had a stronger effect on the U2 pattern. A 5'ss-U1 snRNA complementation experiment suggests that pairing between U1 and the 5'ss occurs after U1 recruitment and contributes to a specific U1:substrate conformation required for efficient U2 and tri-snRNP recruitment.
Keywords:	Base Pairing, {beta}-Galactosidase, Binding Sites, Biological Models, Chromatin Immunoprecipitation, Fungal Genes, Genetic Transcription, Introns, Mutation, Reporter Genes, RNA Splicing, Saccharomyces cerevisiae, Small Nuclear RNA, Spliceosomes
Source:	Molecular Cell
ISSN:	1097-2765
Publisher:	Cell Press
Volume:	19
Number:	1
Page Range:	65-75
Date:	1 July 2005
Official Publication:	https://doi.org/10.1016/j.molcel.2005.05.006
PubMed:	View item in PubMed

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