Inhibition of splicing by serine-arginine rich protein 55 (SRp55) causes the appearance of partially spliced HIV-1 mRNAs in the cytoplasm

Department of Medical Biochemistry & Microbiology, Uppsala University, BMC, 75123 Uppsala, Sweden.
Virus Research (Impact Factor: 2.32). 02/2011; 157(1):82-91. DOI: 10.1016/j.virusres.2011.02.010
Source: PubMed


We have previously shown that SRp55 inhibits splicing from HIV-1 exon 3, thereby generating partially spliced mRNAs encoding HIV-1 vpr. Here we show that SRp55 also inhibits splicing from HIV-1 exon 5 to generate HIV-1 vpu/env mRNA, albeit with lower efficiency. We also show that inhibition of HIV-1 splicing by SRp55 causes the appearance of partially spliced vpu, env and vpr mRNAs in the cytoplasm. SRp55 could also induce production of extracellular p24gag from a rev-defective HIV-1 provirus. These results indicate that SRp55 aids in the generation of partially spliced and unspliced HIV-1 mRNAs.

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    • "Additional rare ‘cryptic’ splice donors (5′ splice sites) and acceptors (3′ splice sites) contribute even more mRNAs (8–13). A complex array of positive and negative cis-acting elements surrounding each splice site regulates the relative abundance of the HIV-1 mRNAs, and disrupting the balance of message ratios impairs viral replication in several models (14–21). Studies have suggested strain-specific splicing patterns may exist (7,22,23). "
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