Viral RNA-binding activity of HIV-2 nucleocapsid protein is inhibited by a synthetic peptide containing the first zinc finger motif of HIV-2.
OBJECTIVE
To analyze the antigenic structure and viral RNA-binding activity of HIV-2GH-1 nucleocapsid protein (NC).


METHODS
Five synthetic peptides corresponding to hydrophilic regions of HIV-2GH-1 NC were prepared. The reactivity of rabbit antisera directed against these synthetic peptides was examined by Western blot (WB) assay, using lysates of purified HIV-2GH-1 virus and HIV-2GH-1-infected cells as antigen. The binding activity of NC to viral RNA synthesized in vitro, was assessed by Northwestern blot (NWB) assay using 32P-labeled RNA as a probe.


RESULTS
One of five antisera against the peptides reacted with a protein of 8 kD (p8) of HIV-2GH-1 in WB. p8 was analyzed for the amino-terminal amino-acid sequence and identified as a portion of NC including two zinc finger motifs (ZFM), comprising the DNA-binding region 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.


CONCLUSIONS
p8 of HIV-2GH-1 NC binds to viral RNA in vitro. The first ZFM in the p8 molecule appears to be essential to binding activity. Functional analysis of synthetic peptides corresponding to ZFM of HIV p8 may provide important information on the development of antiviral agents.
Komatsu
H
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Department of Immunology, School of Hygienic Sciences, Kitasato University, Sagamihara, Japan.
Tozawa
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D000595:Amino Acid Sequence; D000818:Animals; D000956:Antigens, Viral / Q000235:genetics; D002213:Capsid / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D005260:Female; D015683:Gene Products, gag / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D015483:HIV Antibodies; D015498:HIV-2 / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D066298:In Vitro Techniques; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000138:chemical synthesis / Q000235:genetics / Q000494:pharmacology; D011485:Protein Binding / Q000187:drug effects; D012367:RNA, Viral / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000378:metabolism; D011817:Rabbits; D016335:Zinc Fingers / Q000235:genetics
D000956:Antigens, Viral; D015683:Gene Products, gag; D015483:HIV Antibodies; D010446:Peptide Fragments; D012367:RNA, Viral; D016601:RNA-Binding Proteins