Abstract
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.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Base Sequence
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Enhancer Elements, Genetic*
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Exons*
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Gene Expression Regulation, Viral
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Gene Products, env / genetics
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Gene Products, env / metabolism
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Gene Products, nef / genetics
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Gene Products, nef / metabolism
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Gene Products, rev / genetics
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Gene Products, rev / metabolism
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HIV-1 / classification
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HIV-1 / genetics
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HIV-1 / physiology
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HeLa Cells
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Human Immunodeficiency Virus Proteins
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Humans
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Molecular Sequence Data
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Nuclear Proteins / metabolism*
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Phosphoproteins / metabolism*
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RNA Splicing*
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RNA, Messenger / biosynthesis
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RNA, Viral / biosynthesis
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RNA-Binding Proteins
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Ribonucleoprotein, U1 Small Nuclear / metabolism
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Serine-Arginine Splicing Factors
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Spliceosomes
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Viral Regulatory and Accessory Proteins / genetics
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Viral Regulatory and Accessory Proteins / metabolism*
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nef Gene Products, Human Immunodeficiency Virus
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rev Gene Products, Human Immunodeficiency Virus
Substances
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Gene Products, env
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Gene Products, nef
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Gene Products, rev
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Human Immunodeficiency Virus Proteins
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Nuclear Proteins
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Phosphoproteins
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RNA, Messenger
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RNA, Viral
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RNA-Binding Proteins
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Ribonucleoprotein, U1 Small Nuclear
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Viral Regulatory and Accessory Proteins
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nef Gene Products, Human Immunodeficiency Virus
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rev Gene Products, Human Immunodeficiency Virus
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vpu protein, Human immunodeficiency virus 1
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Serine-Arginine Splicing Factors