Faculty Collaboration Database

Serine/arginine-rich proteins contribute to negative regulator of splicing element-stimulated polyadenylation in rous sarcoma virus. J Virol 2007 Oct;81(20):11208-17

Date

08/03/2007

Pubmed ID

17670832

Pubmed Central ID

PMC2045511

DOI

10.1128/JVI.00919-07

Scopus ID

2-s2.0-35148860145 (requires institutional sign-in at Scopus site)   32 Citations

Abstract

Rous sarcoma virus (RSV) requires large amounts of unspliced RNA for replication. Splicing and polyadenylation are coupled in the cells they infect, which raises the question of how viral RNA is efficiently polyadenylated in the absence of splicing. Optimal RSV polyadenylation requires a far-upstream splicing control element, the negative regulator of splicing (NRS), that binds SR proteins and U1/U11 snRNPs and functions as a pseudo-5' splice site that interacts with and sequesters 3' splice sites. We investigated a link between NRS-mediated splicing inhibition and efficient polyadenylation. In vitro, the NRS alone activated a model RSV polyadenylation substrate, and while the effect did not require the snRNP-binding sites or a downstream 3' splice site, SR proteins were sufficient to stimulate polyadenylation. Consistent with this, SELEX-binding sites for the SR proteins ASF/SF2, 9G8, and SRp20 were able to stimulate polyadenylation when placed upstream of the RSV poly(A) site. In vivo, however, the SELEX sites improved polyadenylation in proviral clones only when the NRS-3' splice site complex could form. Deletions that positioned the SR protein-binding sites closer to the poly(A) site eliminated the requirement for the NRS-3' splice site interaction. This indicates a novel role for SR proteins in promoting RSV polyadenylation in the context of the NRS-3' splice site complex, which is thought to bridge the long distance between the NRS and poly(A) site. The results further suggest a more general role for SR proteins in polyadenylation of cellular mRNAs.

Author List

Maciolek NL, McNally MT

Author

Mark T. McNally PhD Associate Professor in the Microbiology and Immunology department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Arginine
Binding Sites
HeLa Cells
Humans
Polyadenylation
Proteins
RNA Splicing
RNA, Viral
Rous sarcoma virus
Serine