Characterisation of new full-length HIV-1 subtype D viruses from South Africa

Loxton, Andre Gareth ; Janse van Rensburg, E. ; Engelbrecht, S. (2004-12)

Thesis (MSc (Medical Virology )--University of Stellenbosch, 2004.

150 leaves printed on single pages, preliminary pages i-vii and numberd pages 1-143. Includes bibliography and figures digitized at 300 dpi grayscale and 300 dpi 24-bit Color to pdf format (OCR), using a Hp Scanjet 8250 Scanner and digitized at 600 dpi grayscale to pdf format (OCR), using a Bizhub 250 Konica Minolta Scanner.

Thesis

ENGLISH ABSTRACT: The first episode of HIV-1 in South Africa was documented in 1982. Homosexual transmission of the virus was the predominate mode of transmission in an epidemic of mainly HIV-1 subtype Band D infections. To date, no full-length sequences of Subtype D strains from South Africa has been reported. Here we describe the characterization and some of the unique features of the Tygerberg HIV-1 subtype D strains. A near full-length 9 kb fragment was obtained through a one step PCR using high molecular weight DNA. Cloning was done successfully with the pCR-XLTapa cloning kit. Large quantities of plasmid DNA was grown and sequenced on both strands of the DNA. ORF determination and subtyping was followed by standard phylogenetic methods to construct evolutionary phylogenetic trees. Subtyping and similarity plots revealed that the sequences from Tygerberg are pure subtype D. All the Tygerberg strains had intact genes with no premature stop codons. At the tip of the V3 loop, the Tygerberg strains have the GOGO motif. R214 has a more variable vpu gene than the rest of the Tygerberg strains, but is still subtype D in this region. No premature stop codons have been observed in the tat gene and the glycosilation of the strains are less than the subtype D consensus. We are the first to report full-length sequences of HIV-1 subtype D strains from South Africa. The sequences represent non-mosaic genomes of subtype D. Our results confirm that the subtype D sequences from the beginning of the HIV-1 epidemic differ from the Subtype D sequences from recent isolates.

AFRIKAANSE OPSOMMING: Die eerste episode van HIV-1 infeksie in Suid Afrika is in 1982 gedokumenteer. Die epidemie het hoofsaaklik uit subtipe B en D bestaan en was deur homoseksuele kontak oorgedra. Geen vollengte subtipe D DNS volgordes van Suid-Afrika is tans beskryf nie. Hier beskryf ons die karakterisering van vollengte subtipe D stamme asook sommige van die unieke eienskappe van die virusse. Die vollengte 9 kb genoom volgorde was verkry deur 'n eenstap PKR reaksie met hoë molekulêre gewig DNS uit te voer. Die 9 kb fragment was suksesvol gekloneer met behulp van die peR-Xl-TOPO klonerings toetsstel. Groot hoeveelhede plasmied DNS was opgegroei en die nukleotied volgorde bepaal op beide stringe van die genoom. Die stamme was gesubtipeer en filogenetiese analise was uitgevoer met standaard metodes. Die volledige DNS volgordes was bepaal en subtipering het daarop gedui dat die stamme van Tygerberg suiwer subtipe D is. Geen premature stop kodons is in die nukleotied volgordes van die Tygerberg stamme gevind nie. By die draai van die varieerbare deel (V3) het al die Tygerberg stamme die GQGQ motief gehad. R214 het 'n meer varieerbare vpu geen, maar behoort steeds tot die subtipe D groep in die gedeelte. Daar was geen premature stop kodons in die tat geen gevind nie en die glikosilasie van die stamme is minder as die van die konsensus subtipe D stam. Ons is die eerste groep om vollengte subtipe D stamme van Suid-Afrika te karakteriseer. Die DNS volgordes verteenwoordig suiwer subtipe D genome. Ons resultate bevestig die van ander dat die nukleotied volgordes van die ouer subtipe D stamme verskil van die nuwer stamme.

Please refer to this item in SUNScholar by using the following persistent URL: http://hdl.handle.net/10019.1/3266
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