       Document 0075
 DOCN  M9490075
 TI    Initiation of reverse transcription during cell-to-cell transmission of
       human immunodeficiency virus infection uses pre-existing reverse
       transcriptase.
 DT    9411
 AU    Li P; Stephenson AJ; Brennan PA; Karageorgos L; Kok T; Kuiper LJ; Swift
       J; Burrell CJ; National Centre for HIV Virology Research, Institute of
       Medical; and Veterinary Science, Adelaide, Australia.
 SO    J Gen Virol. 1994 Aug;75 ( Pt 8):1917-26. Unique Identifier : AIDSLINE
       MED/94321981
 AB    H3B cells, a laboratory clone of H9 cells persistently infected with the
       HTLV-IIIB strain of human immunodeficiency virus (HIV), contained
       significant levels of cell-associated reverse transcriptase (RT)
       activity measured by in vitro assays using either exogenous or
       endogenous templates. The cell-associated RT activity detected using
       exogenous template was almost wholly in a soluble (non-sedimentable)
       form whereas endogenous activity sedimented as a particulate structure
       associated with viral RNA. Despite this, H3B cells did not contain
       episomal HIV DNA detectable by Southern blot, indicating that in vivo
       reverse transcription was not occurring to any significant extent in
       these cells. However, when susceptible HUT 78 cells were infected by
       co-cultivation with H3B cells, dramatic synthesis of episomal HIV DNA
       occurred. Concurrently with this de novo initiation of reverse
       transcription, however, we found no detectable change in intracellular
       levels or cleavage profiles of immunoprecipitable RT polypeptides.
       Finally, actinomycin D pre-treatment of H3B cells to prevent de novo
       transcription from donor cell proviral DNA after co-cultivation did not
       affect the initiation of in vivo reverse transcription following
       cell-to-cell HIV infection. These results demonstrated that cells
       persistently infected with HIV contained significant fully cleaved
       cell-associated RT in a form that was active in vitro but not in vivo
       and that following cell-to-cell transmission of HIV infection to
       susceptible cells, de novo reverse transcription was initiated without
       detectable evidence of further synthesis or proteolytic processing of
       HIV RT. The nature of this initiation process requires further study.
 DE    Biological Transport  Blotting, Western  Cells, Cultured  Human
       HIV/ENZYMOLOGY/*GROWTH & DEVELOPMENT/GENETICS/ULTRASTRUCTURE
       Microscopy, Electron  Precipitin Tests  Reverse
       Transcriptase/*METABOLISM  RNA, Viral/ISOLATION & PURIF  Support,
       Non-U.S. Gov't  *Transcription, Genetic  Virus Integration  JOURNAL
       ARTICLE

       SOURCE: National Library of Medicine.  NOTICE: This material may be
       protected by Copyright Law (Title 17, U.S.Code).

