Tags

Type your tag names separated by a space and hit enter

Negative and positive mRNA splicing elements act competitively to regulate human immunodeficiency virus type 1 vif gene expression.
J Virol 2008; 82(8):3921-31JV

Abstract

Over 40 different human immunodeficiency virus type 1 (HIV-1) mRNAs are produced by alternative splicing of the primary HIV-1 RNA transcripts. In addition, approximately half of the viral RNA remains unspliced and is used as genomic RNA and as mRNA for the Gag and Pol gene products. Regulation of splicing at the HIV-1 3' splice sites (3'ss) requires suboptimal polypyrimidine tracts, and positive or negative regulation occurs through the binding of cellular factors to cis-acting splicing regulatory elements. We have previously shown that splicing at HIV-1 3'ss A1, which produces single-spliced vif mRNA and promotes the inclusion of HIV exon 2 into both completely and incompletely spliced viral mRNAs, is increased by optimizing the 5' splice site (5'ss) downstream of exon 2 (5'ss D2). Here we show that the mutations within 5'ss D2 that are predicted to lower or increase the affinity of the 5'ss for U1 snRNP result in reduced or increased Vif expression, respectively. Splicing at 5'ss D2 was not necessary for the effect of 5'ss D2 on Vif expression. In addition, we have found that mutations of the GGGG motif proximal to the 5'ss D2 increase exon 2 inclusion and Vif expression. Finally, we report the presence of a novel exonic splicing enhancer (ESE) element within the 5'-proximal region of exon 2 that facilitates both exon inclusion and Vif expression. This ESE binds specifically to the cellular SR protein SRp75. Our results suggest that the 5'ss D2, the proximal GGGG silencer, and the ESE act competitively to determine the level of vif mRNA splicing and Vif expression. We propose that these positive and negative splicing elements act together to allow the accumulation of vif mRNA and unspliced HIV-1 mRNA, compatible with optimal virus replication.

Authors+Show Affiliations

Department of Microbiology, University of Iowa, Iowa City, IA 52242, USA.No affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, N.I.H., Extramural

Language

eng

PubMed ID

18272582

Citation

Exline, C M., et al. "Negative and Positive mRNA Splicing Elements Act Competitively to Regulate Human Immunodeficiency Virus Type 1 Vif Gene Expression." Journal of Virology, vol. 82, no. 8, 2008, pp. 3921-31.
Exline CM, Feng Z, Stoltzfus CM. Negative and positive mRNA splicing elements act competitively to regulate human immunodeficiency virus type 1 vif gene expression. J Virol. 2008;82(8):3921-31.
Exline, C. M., Feng, Z., & Stoltzfus, C. M. (2008). Negative and positive mRNA splicing elements act competitively to regulate human immunodeficiency virus type 1 vif gene expression. Journal of Virology, 82(8), pp. 3921-31. doi:10.1128/JVI.01558-07.
Exline CM, Feng Z, Stoltzfus CM. Negative and Positive mRNA Splicing Elements Act Competitively to Regulate Human Immunodeficiency Virus Type 1 Vif Gene Expression. J Virol. 2008;82(8):3921-31. PubMed PMID: 18272582.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Negative and positive mRNA splicing elements act competitively to regulate human immunodeficiency virus type 1 vif gene expression. AU - Exline,C M, AU - Feng,Z, AU - Stoltzfus,C M, Y1 - 2008/02/13/ PY - 2008/2/15/pubmed PY - 2008/4/11/medline PY - 2008/2/15/entrez SP - 3921 EP - 31 JF - Journal of virology JO - J. Virol. VL - 82 IS - 8 N2 - Over 40 different human immunodeficiency virus type 1 (HIV-1) mRNAs are produced by alternative splicing of the primary HIV-1 RNA transcripts. In addition, approximately half of the viral RNA remains unspliced and is used as genomic RNA and as mRNA for the Gag and Pol gene products. Regulation of splicing at the HIV-1 3' splice sites (3'ss) requires suboptimal polypyrimidine tracts, and positive or negative regulation occurs through the binding of cellular factors to cis-acting splicing regulatory elements. We have previously shown that splicing at HIV-1 3'ss A1, which produces single-spliced vif mRNA and promotes the inclusion of HIV exon 2 into both completely and incompletely spliced viral mRNAs, is increased by optimizing the 5' splice site (5'ss) downstream of exon 2 (5'ss D2). Here we show that the mutations within 5'ss D2 that are predicted to lower or increase the affinity of the 5'ss for U1 snRNP result in reduced or increased Vif expression, respectively. Splicing at 5'ss D2 was not necessary for the effect of 5'ss D2 on Vif expression. In addition, we have found that mutations of the GGGG motif proximal to the 5'ss D2 increase exon 2 inclusion and Vif expression. Finally, we report the presence of a novel exonic splicing enhancer (ESE) element within the 5'-proximal region of exon 2 that facilitates both exon inclusion and Vif expression. This ESE binds specifically to the cellular SR protein SRp75. Our results suggest that the 5'ss D2, the proximal GGGG silencer, and the ESE act competitively to determine the level of vif mRNA splicing and Vif expression. We propose that these positive and negative splicing elements act together to allow the accumulation of vif mRNA and unspliced HIV-1 mRNA, compatible with optimal virus replication. SN - 1098-5514 UR - https://www.unboundmedicine.com/medline/citation/18272582/Negative_and_positive_mRNA_splicing_elements_act_competitively_to_regulate_human_immunodeficiency_virus_type_1_vif_gene_expression_ L2 - http://jvi.asm.org/cgi/pmidlookup?view=long&pmid=18272582 DB - PRIME DP - Unbound Medicine ER -