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Abstract
Negative sense transcripts in HIV-1: the role and regulation of vpo/Vpo
Barbagallo M.S.1, Deacon N.J.1, Mosse J.A.1
As well as the nine proteins encoded on the positive sense strand of the HIV-1 genome, a tenth, negative sense ORF (ASP or vpo), opposite the env gene and spanning the gp120/gp41 junction has also been identified. Transcription of vpo has been observed to be regulated by LTR sequences and to occur early in infection, at the same time as regulatory gene transcription. The role of the vpo transcript and/or its translation product and its mechanism of regulation are yet to be elucidated. We have compared the negative sense sequences encoding the vpo transcript across all subtypes of HIV-1. The sequence of encoded Vpo protein is highly conserved, presenting some unique sequence motifs, including several cysteine rich regions and a PxxP motif. Also highly conserved is a series of sORFs upstream of vpo, indicating their potential role in regulation of vpo expression. This region (from HIV-1NL4.3) has been cloned in front of the reporter gene EGFP. We have observed that the presence of the entire series of sORFs inhibits expression of EGFP. In contrast, EGFP is expressed if only the last sORF (immediately upstream of vpo) is present. Isolation of cDNA from HEK293 cells transfected with various combinations of these sORFs has indicated splicing of the region. Experiments in which the AUG codon of the last sORF was mutated have shown that this sORF is required for the expression of the reporter gene. These results provide evidence for a possible regulatory role of sORFs in expression of this tenth, negative sense, transcript. In addition the high conservation of vpo and its sORFs across all HIV-1 subtypes supports the argument for a possible functional role for the vpo gene product.
4th IAS Conference on HIV Pathogenesis, Treatment and Prevention
Abstract no.
WEPEA029
Suggested Citation
"BarbagalloM.S., et al.
Negative sense transcripts in HIV-1: the role and regulation of vpo/Vpo.
Poster exhibition:
4th IAS Conference on HIV Pathogenesis, Treatment and Prevention:
Abstract no.
WEPEA029"
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