Interaction between the RNA binding domains of Ser-Arg splicing factor 1 and U1-70K snRNP protein determines early spliceosome assembly

Cho, S. Y., Hoang, A., Sinha, R., Zhong, X. Y., Fu, X. D., Krainer, A. R., Ghosh, G. (May 2011) Interaction between the RNA binding domains of Ser-Arg splicing factor 1 and U1-70K snRNP protein determines early spliceosome assembly. Proceedings of the National Academy of Sciences of the United States of America, 108 (20). pp. 8233-8238. ISSN 0027-8424

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Abstract

It has been widely accepted that the early spliceosome assembly begins with U1 small nuclear ribonucleoprotein (U1 snRNP) binding to the 5' splice site (5' SS), which is assisted by the Ser/Arg (SR)-rich proteins in mammalian cells. In this process, the RS domain of SR proteins is thought to directly interact with the RS motif of U1-70K, which is subject to regulation by RS domain phosphorylation. Here we report that the early spliceosome assembly event is mediated by the RNA recognition domains (RRM) of serine/arginine-rich splicing factor 1 (SRSF1), which bridges the RRM of U1-70K to pre-mRNA by using the surface opposite to the RNA binding site. Specific mutation in the RRM of SRSF1 that disrupted the RRM-RRM interaction also inhibits the formation of spliceosomal E complex and splicing. We further demonstrate that the hypo-phosphorylated RS domain of SRSF1 interacts with its own RRM, thus competing with U1-70K binding, whereas the hyper-phosphorylated RS domain permits the formation of a ternary complex containing ESE, an SR protein, and U1 snRNP. Therefore, phosphorylation of the RS domain in SRSF1 appears to induce a key molecular switch from intra-to intermolecular interactions, suggesting a plausible mechanism for the documented requirement for the phosphorylation/dephosphorylation cycle during pre-mRNA splicing.

Item Type: Paper
Uncontrolled Keywords: RNA splicing spliceosome complex exonic splicing enhancer protein phosphorylation pre-messenger-rna sr proteins rs domain gene-expression factor asf/sf2 rich domain in-vivo phosphorylation dephosphorylation enhancer
Subjects: bioinformatics > genomics and proteomics > genetics & nucleic acid processing > protein structure, function, modification > protein types > snRMP
bioinformatics > genomics and proteomics > genetics & nucleic acid processing > protein structure, function, modification > protein types > spliceosome complex
CSHL Authors:
Communities: CSHL labs > Krainer lab
CSHL Cancer Center Program > Gene Regulation and Cell Proliferation
Depositing User: CSHL Librarian
Date: 17 May 2011
Date Deposited: 09 Nov 2011 14:46
Last Modified: 03 Jan 2018 16:22
PMCID: PMC3100968
Related URLs:
URI: https://repository.cshl.edu/id/eprint/15620

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