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Virol J. 2008; 5: 99.
Published online 2008 August 23. doi: 10.1186/1743-422X-5-99.
PMCID: PMC2553080
A comprehensive analysis of the naturally occurring polymorphisms in HIV-1 Vpr: Potential impact on CTL epitopes
Alagarsamy Srinivasan,corresponding author1 Velpandi Ayyavoo,corresponding author2 Sundarasamy Mahalingam,3 Aarthi Kannan,1,4 Anne Boyd,1 Debduti Datta,3 Vaniambadi S Kalyanaraman,5 Anthony Cristillo,5 Ronald G Collman,6 Nelly Morellet,7 Bassel E Sawaya,8 and Ramachandran Murali9
1Thomas Jefferson University, Department of Microbiology and Immunology, Jefferson Alumni Hall Rm 461, 1020 Locust Street, Philadelphia, PA 19107, USA
2University of Pittsburgh, Department of Infectious Diseases & Microbiology, Parran Hall Rm 439, 130 DeSoto Street, Pittsburgh, PA 15261, USA
3Department of Biotechnology, Indian Institute of Technology Madras, Chennai 600036, India
4Wellesley College, 21 Wellesley College Rd Unit 7430, Wellesley, MA 02481, USA
5Advanced Bioscience Laboratories, Inc., 5510 Nicholson Lane, Kensington, MD 20895, USA
6University of Pennsylvania School of Medicine, 522 Johnson Pavilion, 36th and Hamilton Walk, Philadelphia PA 19104, USA
7Unite de Pharmacologie Chimique et Genetique, INSERM, Avenue de l'Observatoire, Paris Cedex 06, France
8Department of Neuroscience, Center for Neurovirology, Temple University School of Medicine, Philadelphia, PA 19122, USA
9University of Pennsylvania School of Medicine, Dept of Pathology and Laboratory Medicine, 243 John Morgan, Philadelphia PA 19104, USA
corresponding authorCorresponding author.
Alagarsamy Srinivasan: alagarsamy.srinivasan/at/gmail.com; Velpandi Ayyavoo: velpandi/at/pitt.edu; Sundarasamy Mahalingam: Mahalingam/at/iitm.ac.in; Aarthi Kannan: akannan/at/wellesley.edu; Anne Boyd: annekboyd/at/gmail.com; Debduti Datta: debduti.datta/at/gmail.com; Vaniambadi S Kalyanaraman: vs.kaly/at/ablinc.com; Anthony Cristillo: Anthony.cristillo/at/ablinc.com; Ronald G Collman: collmanr/at/mail.med.upenn.edu; Nelly Morellet: Morellet/at/pharmacie.univ-paris5.fr; Bassel E Sawaya: sawaya/at/temple.edu; Ramachandran Murali: murali/at/xray.med.upenn.edu
Received July 7, 2008; Accepted August 23, 2008.
Abstract
The enormous genetic variability reported in HIV-1 has posed problems in the treatment of infected individuals. This is evident in the form of HIV-1 resistant to antiviral agents, neutralizing antibodies and cytotoxic T lymphocytes (CTLs) involving multiple viral gene products. Based on this, it has been suggested that a comprehensive analysis of the polymorphisms in HIV proteins is of value for understanding the virus transmission and pathogenesis as well as for the efforts towards developing anti-viral therapeutics and vaccines. This study, for the first time, describes an in-depth analysis of genetic variation in Vpr using information from global HIV-1 isolates involving a total of 976 Vpr sequences. The polymorphisms at the individual amino acid level were analyzed. The residues 9, 33, 39, and 47 showed a single variant amino acid compared to other residues. There are several amino acids which are highly polymorphic. The residues that show ten or more variant amino acids are 15, 16, 28, 36, 37, 48, 55, 58, 59, 77, 84, 86, 89, and 93. Further, the variant amino acids noted at residues 60, 61, 34, 71 and 72 are identical. Interestingly, the frequency of the variant amino acids was found to be low for most residues. Vpr is known to contain multiple CTL epitopes like protease, reverse transcriptase, Env, and Gag proteins of HIV-1. Based on this, we have also extended our analysis of the amino acid polymorphisms to the experimentally defined and predicted CTL epitopes. The results suggest that amino acid polymorphisms may contribute to the immune escape of the virus. The available data on naturally occurring polymorphisms will be useful to assess their potential effect on the structural and functional constraints of Vpr and also on the fitness of HIV-1 for replication.