Open AccessA Bidirectional SF2/ASF- and SRp40-Dependent Splicing Enhancer Regulates Human Immunodeficiency Virus Type 1 rev , env , vpu , and nef Gene Expression
Author(s) -
Massimo Caputi,
Marcel Freund,
Susanne Kammler,
Corinna Asang,
Heiner Schaal
Publication year - 2004
Publication title -
journal of virology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.617
H-Index - 292
eISSN - 1070-6321
pISSN - 0022-538X
DOI - 10.1128/jvi.78.12.6517-6526.2004
Subject(s) - snrnp , rna splicing , biology , enhancer , splice , splice site mutation , gene , alternative splicing , virology , genetics , rna , microbiology and biotechnology , messenger rna , gene expression
The integrated human immunodeficiency virus type 1 (HIV-1) genome is transcribed in a single pre-mRNA that is alternatively spliced into more than 40 mRNAs. We characterized a novel bidirectional exonic splicing enhancer (ESE) that regulates the expression of the HIV-1 env, vpu, rev, and nef mRNAs. The ESE is localized downstream of the vpu-, env-, and nef-specific 3' splice site no. 5. SF2/ASF and SRp40 activate the ESE and are required for efficient 3' splice site usage and binding of the U1 snRNP to the downstream 5' splice site no. 4. U1 snRNP binding to the 5' splice site no. 4 is required for splicing of the rev and nef mRNAs and to increase expression of the partially spliced env mRNA. Finally, our results indicate that this ESE is necessary for the recruitment of the U1 snRNP to the 5' splice site no. 4, even when the 5' splice site and the U1 snRNA have been mutated to obtain a perfect complementary match. The ESE characterized here is highly conserved in most viral subtypes.