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Alternative splicing of HIV-1 mRNA modulates viral protein expression, replication and infectivity.
Purcell DF; Englund G; Martin MA; Laboratory of Molecular Microbiology,
December 30, 1995
Natl Conf Hum Retroviruses Relat Infect (1st). 1993 Dec 12-16;:124.

Multiple RNA splicing sites exist within HIV-1 genomic RNA and these enable the synthesis of many mRNAs for each of several viral proteins. We evaluated the biological significance of the alternatively spliced mRNA species during productive HIV-1 infections of peripheral blood lymphocytes, human T cell lines, and monocyte-derived macrophage to determine the potential role of alternative RNA splicing in the regulation of HIV-1 replication and infection. Firstly, we used a semi-quantitative PCR assay to determine the relative abundance of the diverse array of alternatively spliced HIV-1 mRNAs. HIV-1 strains tropic for monocyte-derived macrophage preferentially utilize splice acceptors for rev and vpu/env that are not frequently used by T-cell tropic viruses. Secondly, the effect of altered RNA processing was measured following mutagenesis of the major 5' splice donor and several cryptic, constitutive, and competing 3' splice acceptor motifs of HIV-1NL4-3. Mutations that ablated constitutive splice sites led to the activation of new cryptic sites; some of these preserved biological function. Mutations that ablated competing splice acceptor sites caused marked alterations in the pool of virus-derived mRNAs and, in some instances, markedly altered virus infectivity and/or the profile of virus proteins. Redundant RNA splicing signals in the HIV-1 genome and alternatively spliced mRNAs provide a mechanism for regulating the relative proportions of HIV-1 proteins and, in some cases, viral infectivity.

*Alternative Splicing Cell Line Human HIV-1/*GENETICS/PATHOGENICITY Macrophages/VIROLOGY Mutation Polymerase Chain Reaction RNA Processing, Post-Transcriptional RNA, Messenger/*GENETICS T-Lymphocytes/VIROLOGY Virus Replication/*GENETICS ABSTRACT