title: Effect on HIV-1 gene expression, Tat-Vpr interaction and cell apoptosis by natural variants of HIV-1 Tat exon 1 and Vpr from Northern India.
abstract: BACKGROUND
  Since HIV-1 Tat and Vpr genes are involved in promoter transactivation, apoptosis, etc, we carried out studies to find out nature and extent of natural variation in the two genes from seropositive patients from Northern India and determined their functional implications.
  
  
  METHODS
  HIV-1 tat exon 1 and vpr were amplified from the genomic DNA isolated from the blood of HIV-1 infected individuals using specific primers by Polymerase Chain reaction (PCR) and subjected to extensive genetic analysis (CLUSTAL W, Simplot etc). Their expression was monitored by generating myc fusion clones. Tat exon 1 and Vpr variants were co-transfected with the reporter gene construct (LTR-luc) and their transactivation potential was monitored by measuring luciferase activity. Apoptosis and cell cycle analysis was done by Propidium Iodide (PI) staining followed by FACS.
  
  
  RESULTS
  Exon 1 of tat was amplified from 21 samples and vpr was amplified from 16 samples. One of the Tat exon 1 variants showed phylogenetic relatedness to subtype B & C and turned out to be a unique recombinant. Two of the Vpr variants were B/C/D recombinants. These natural variations were found to have no impact on the stability of Tat and Vpr. These variants differed in their ability to transactivate B LTR and C LTR promoters. B/C recombinant Tat showed better co-operative interaction with Vpr. B/C/D recombination in Vpr was found to have no effect on its co-operativity with Tat. Recombinant Tat (B/C) induced more apoptosis than wild type B and C Tat. The B/C/D recombination in Vpr did not affect its G2 arrest induction potential but reduced its apoptosis induction ability.
  
  
  CONCLUSIONS
  Extensive sequence and region-specific variations were observed in Tat and Vpr genes from HIV-1 infected individuals from Northern India. These variations have functional implications & therefore important for the pathogenicity of virus.
authors.affiliation: Department of Microbiology, University College of Medical Sciences and Guru Teg Bahadur Hospital, Delhi, India.
authors.forename: Sneh
authors.initials: S
authors.lastname: Lata
authors.affiliation: Department of Microbiology, University College of Medical Sciences and Guru Teg Bahadur Hospital, Delhi, India ; Laboratory of Virology, National Institute of Immunology, New Delhi, India.
authors.forename: Larance
authors.initials: L
authors.lastname: Ronsard
authors.affiliation: Department of Microbiology, University College of Medical Sciences and Guru Teg Bahadur Hospital, Delhi, India ; Laboratory of Virology, National Institute of Immunology, New Delhi, India.
authors.forename: Vikas
authors.initials: V
authors.lastname: Sood
authors.affiliation: Department of Microbiology, University College of Medical Sciences and Guru Teg Bahadur Hospital, Delhi, India.
authors.forename: Sajad A
authors.initials: SA
authors.lastname: Dar
authors.affiliation: Department of Microbiology, University College of Medical Sciences and Guru Teg Bahadur Hospital, Delhi, India.
authors.forename: Vishnampettai G
authors.initials: VG
authors.lastname: Ramachandran
authors.affiliation: Department of Microbiology, University College of Medical Sciences and Guru Teg Bahadur Hospital, Delhi, India.
authors.forename: Shukla
authors.initials: S
authors.lastname: Das
authors.affiliation: Laboratory of Virology, National Institute of Immunology, New Delhi, India.
authors.forename: Akhil C
authors.initials: AC
authors.lastname: Banerjea
mesh_terms: D000293:Adolescent; D000328:Adult; D017209:Apoptosis / Q000235:genetics*; D015153:Blotting, Western; D004591:Electrophoresis, Polyacrylamide Gel; D005091:Exons / Q000235:genetics; D005260:Female; D005434:Flow Cytometry; D015967:Gene Expression Regulation, Viral / Q000235:genetics*; D016336:Gene Products, vpr / Q000235:genetics*; D015497:HIV-1 / Q000235:genetics*; D006367:HeLa Cells; D006801:Humans; D007194:India; D008297:Male; D008875:Middle Aged; D055815:Young Adult; D054322:tat Gene Products, Human Immunodeficiency Virus / Q000235:genetics*
chemical_list: D016336:Gene Products, vpr; D054322:tat Gene Products, Human Immunodeficiency Virus