Human immunodeficiency virus type 1 integrase mutants retain in vitro integrase activity yet fail to integrate viral DNA efficiently during infection.
AUTOR(ES)
Leavitt, A D
RESUMO
The viral integrase (IN) protein is the only viral protein known to be required for integration of the human immunodeficiency virus type 1 (HIV-1) genome into the host cell DNA, a step in the viral life cycle that is essential for viral replication. To better understand the relationship between in vitro IN activity and IN-mediated integration of viral DNA in an infected cell, we characterized the effects of 13 IN mutations on viral replication in cultured cells. Using HIV-1 genomes that express the hygromycin resistance gene and do not express the HIV-1 env gene, we generated stocks of pseudotype virus coated with the murine leukemia virus amphotropic envelope glycoprotein, containing either wild-type or mutant HIV-1 IN. All mutants produced normal amounts of physical particles, as measured by reverse transcriptase activity and capsid protein (p24) concentration, but they formed three groups based on infectious titer and synthesis of viral DNA. Changes at the three highly conserved acidic residues in the IN core domain (D-64, D-116, and E-152) impair provirus formation without affecting viral DNA synthesis or the accumulation of viral DNA in the nucleus of the infected cell, a phenotype predicted by each mutant's lack of in vitro integrase activity. Mutations at positions N-120, R-199, and W-235 minimally affect in vitro integrase activity, but infectious titers are severely reduced, despite normal synthesis of viral DNA, implying a defect during integration in vivo. Mutations in the zinc binding region (H12C, H16V, and H16C), S81R, and a deletion of residues 32 through 275 yield noninfectious particles that synthesize little or no viral DNA following infection, despite wild-type levels of reverse transcriptase activity and viral RNA in the particles. The two latter classes of mutants suggest that IN can affect DNA synthesis or integration during infection in ways that are not appreciated from currently used assays in vitro.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=189872Documentos Relacionados
- Human immunodeficiency virus type 1 integrase: effects of mutations on viral ability to integrate, direct viral gene expression from unintegrated viral DNA templates, and sustain viral propagation in primary cells.
- Evaluation of the Functional Involvement of Human Immunodeficiency Virus Type 1 Integrase in Nuclear Import of Viral cDNA during Acute Infection
- Association of integrase, matrix, and reverse transcriptase antigens of human immunodeficiency virus type 1 with viral nucleic acids following acute infection.
- Kinetics of cytokine expression during primary human immunodeficiency virus type 1 infection.
- Kinetics of human immunodeficiency virus type 1 (HIV-1) DNA and RNA synthesis during primary HIV-1 infection.