title: Characterization of the South African HIV type 1 subtype C complete 5' long terminal repeat, nef, and regulatory genes.
abstract: Human immunodeficiency virus type 1 (HIV-1) subtype C has become the major etiological agent in the global and especially African epidemic. To gain better understanding of the genetic diversity and rapid transmission of HIV-1 subtype C, we have characterized the complete 5' long terminal repeat (LTR) region along with the regulatory genes tat and rev as well as the accessory gene nef of 14 South African HIV-1 subtype C isolates. Phylogenetic analysis revealed a subtype C 5' LTR cluster, as well as subclustering of our nef sequences with various subtype C strains separate from the India and China subclusters. At least 3 NF-kappaB sites were present in the 5' LTR of most isolates and 13 isolates had the subtype C-specific Rev truncation. Some length variation in exon 2 and the absence of a critical cysteine were found in Tat. Residue variation in the myristoylation signal and motifs involved in CD4 and MHC-I downregulation was recorded in our nef gene sequences.
authors.affiliation: Department of Medical Virology, University of Stellenbosch, Tygerberg 7505, South Africa.
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Scriba
authors.forename: Tania
authors.initials: T
authors.lastname: de Villiers
authors.forename: Florette K
authors.initials: FK
authors.lastname: Treurnicht
authors.forename: Jan
authors.initials: J
authors.lastname: zur Megede
authors.forename: Susan W
authors.initials: SW
authors.lastname: Barnett
authors.forename: Susan
authors.initials: S
authors.lastname: Engelbrecht
authors.forename: Estrelita Janse
authors.initials: EJ
authors.lastname: van Rensburg
mesh_terms: D000353:Africa, Southern / Q000453:epidemiology; D000595:Amino Acid Sequence; D015754:Genes, nef; D015757:Genes, rev; D015756:Genes, tat; D015658:HIV Infections / Q000453:epidemiology / Q000821:virology*; D016325:HIV Long Terminal Repeat; D015497:HIV-1 / Q000145:classification / Q000235:genetics*; D006801:Humans; D008969:Molecular Sequence Data; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid