Our long-term goals are to develop a detailed mechanistic understanding of HIV-1 proteins using large-scale mutagenesis to probe structure/function relationships. We have developed technologies that have allowed us to make the HIV-1 protease one of the most thoroughly characterized proteins analyzed by genetic techniques. The continued application of these techniques will provide an important source of information that can be combined with other approaches, such as biochemical and structural analysis, to yield important insight into key enzymes in the viral replication cycle. The specific focus of the proposed research is to carry out a detailed genetic analysis of several of the HIV-1 pol gene products: protease, reverse transcriptase, and RNase H. The basis for this work is our previous mutational mapping of the viral protease in which we characterized mutants with substitutions at each amino acid of the protease. We will continue to define the sequence requirements for protease activity and search for novel or conditional mutant phenotypes that give insight into the role of specific amino acids in protease function. We will also characterize the processing pathway in the maturation of virions, and use mutagenesis to define the sequence requirements of the protease cleavage sites placed within the natural substrate. The role of the protease in cell killing will also be explored. We will extend our genetic analysis to the reverse transcriptase and RNase H activities of HIV-1. Through large-scale mutagenesis, functionally important domains of these proteins will be identified and novel phenotypes uncovered. These studies will provide important information about the function organization of these two poorly understood enzymes.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
5R01AI025321-08
Application #
2062954
Study Section
Special Emphasis Panel (ARR (V1))
Project Start
1987-09-30
Project End
1995-05-31
Budget Start
1994-06-01
Budget End
1995-05-31
Support Year
8
Fiscal Year
1994
Total Cost
Indirect Cost
Name
University of North Carolina Chapel Hill
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
078861598
City
Chapel Hill
State
NC
Country
United States
Zip Code
27599
Resch, Wolfgang; Parkin, Neil; Watkins, Terri et al. (2005) Evolution of human immunodeficiency virus type 1 protease genotypes and phenotypes in vivo under selective pressure of the protease inhibitor ritonavir. J Virol 79:10638-49
Watkins, Terri; Resch, Wolfgang; Irlbeck, David et al. (2003) Selection of high-level resistance to human immunodeficiency virus type 1 protease inhibitors. Antimicrob Agents Chemother 47:759-69
Resch, Wolfgang; Ziermann, Rainer; Parkin, Neil et al. (2002) Nelfinavir-resistant, amprenavir-hypersusceptible strains of human immunodeficiency virus type 1 carrying an N88S mutation in protease have reduced infectivity, reduced replication capacity, and reduced fitness and process the Gag polyprotein precursor ab J Virol 76:8659-66
Pettit, Steve C; Henderson, Gavin J; Schiffer, Celia A et al. (2002) Replacement of the P1 amino acid of human immunodeficiency virus type 1 Gag processing sites can inhibit or enhance the rate of cleavage by the viral protease. J Virol 76:10226-33
Resch, W; Parkin, N; Stuelke, E L et al. (2001) A multiple-site-specific heteroduplex tracking assay as a tool for the study of viral population dynamics. Proc Natl Acad Sci U S A 98:176-81
Shehu-Xhilaga, M; Kraeusslich, H G; Pettit, S et al. (2001) Proteolytic processing of the p2/nucleocapsid cleavage site is critical for human immunodeficiency virus type 1 RNA dimer maturation. J Virol 75:9156-64
Wrobel, J A; Conrad, M J; Bloedon, E et al. (2000) Analysis of HIV type 1 reverse transcriptase: comparing sequences of viral isolates with mutational data. AIDS Res Hum Retroviruses 16:2049-54
Vaillancourt, M; Irlbeck, D; Smith, T et al. (1999) The HIV type 1 protease inhibitor saquinavir can select for multiple mutations that confer increasing resistance. AIDS Res Hum Retroviruses 15:355-63
Wrobel, J A; Chao, S F; Conrad, M J et al. (1998) A genetic approach for identifying critical residues in the fingers and palm subdomains of HIV-1 reverse transcriptase. Proc Natl Acad Sci U S A 95:638-45
Pettit, S C; Sheng, N; Tritch, R et al. (1998) The regulation of sequential processing of HIV-1 Gag by the viral protease. Adv Exp Med Biol 436:15-25

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