Moloney Murine Leukemia Virus Integrase Protein Augments Viral DNA Synthesis in Infected Cells

AUTOR(ES)

Lai, Lilin

FONTE

American Society for Microbiology

RESUMO

Mutations in the IN domain of retroviral DNA may affect multiple steps of the virus life cycle, suggesting that the IN protein may have other functions in addition to its integration function. We previously reported that the human immunodeficiency virus type 1 IN protein is required for efficient viral DNA synthesis and that this function requires specific interaction with other viral components but not enzyme (integration) activity. In this report, we characterized the structure and function of the Moloney murine leukemia virus (MLV) IN protein in viral DNA synthesis. Using an MLV vector containing green fluorescent protein as a sensitive reporter for virus infection, we found that mutations in either the catalytic triad (D184A) or the HHCC motif (H61A) reduced infectivity by approximately 1,000-fold. Mutations that deleted the entire IN (ΔIN) or 34 C-terminal amino acid residues (Δ34) were more severely defective, with infectivity levels consistently reduced by 10,000-fold. Immunoblot analysis indicated that these mutants were similar to wild-type MLV with respect to virion production and proteolytic processing of the Gag and Pol precursor proteins. Using semiquantitative PCR to analyze viral cDNA synthesis in infected cells, we found the Δ34 and ΔIN mutants to be markedly impaired while the D184A and H61A mutants synthesized cDNA at levels similar to the wild type. The DNA synthesis defect was rescued by complementing the Δ34 and ΔIN mutants in trans with either wild-type IN or the D184A mutant IN, provided as a Gag-IN fusion protein. However, the DNA synthesis defect of ΔIN mutant virions could not be complemented with the Δ34 IN mutant. Taken together, these analyses strongly suggested that the MLV IN protein itself is required for efficient viral DNA synthesis and that this function may be conserved among other retroviruses.

Documentos Relacionados

• Sequence-specific binding of DNA by the Moloney murine leukemia virus integrase protein.
• Virus-specific RNA synthesis in interferon-treated mouse cells productively infected with Moloney murine leukemia virus.
• Footprints on the viral DNA ends in Moloney murine leukemia virus preintegration complexes reflect a specific association with integrase
• A Chimeric Ty3/Moloney Murine Leukemia Virus Integrase Protein Is Active In Vivo
• Viral gene expression in murine sarcoma virus(murine leukemia virus)-infected cells.