VIRAL RNA-BINDING ACTIVITY OF HIV-2 NUCLEOCAPSID PROTEIN IS INHIBITEDBY A SYNTHETIC PEPTIDE-CONTAINING THE FIRST ZINC-FINGER MOTIF OF HIV-2

Objective: To analyze the antigenic structure and viral RNA-binding ac tivity of HIV-2(GH-1) nucleocapsid protein (NC). Methods: Five synthet ic peptides corresponding to hydrophilic regions of HIV-2(GH-1) NC wer e prepared. The reactivity of rabbit antisera directed against these s ynthetic peptides was examined by Western blot (WB) assay, using lysat es of purified HIV-2(GH-1) virus and HIV-2(GH-1)-infected cells as ant igen. The binding activity of NC to viral RNA synthesized in vitro, wa s assessed by Northwestern blot (NWB) assay using P-32-labeled RNA as a probe. Results: One of five antisera against the peptides reacted wi th a protein of 8 kD (p8) of HIV-2(GH-1) in WB. P8 Was analyzed for th e amino-terminal amino-acid sequence and identified as a portion of NC including two zinc finger motifs (ZFM), comprising the DNA-binding re gion in the molecule. The binding of the RNA probe to p8 was observed by NWB and did not always depend on zinc. In competition experiments, the reactivity of p8 with the RNA probe ceased to be evident following preincubation of the probe with a peptide containing the first ZFM in the molecule. Conclusion: p8 of HIV-2(GH-1) NC binds to viral RNA in vitro. The first ZFM in the p8 molecule appears to be essential to bin ding activity. Functional analysis of synthetic peptides corresponding to ZFM of HIV p8 may provide important information on the development of antiviral agents.