Document 0407
 DOCN  M9490407
 TI    The role of upstream U3 sequences in the pathogenesis of simian
       immunodeficiency virus-induced AIDS in rhesus monkeys.
 DT    9411
 AU    Ilyinskii PO; Daniel MD; Simon MA; Lackner AA; Desrosiers RC; New
       England Regional Primate Research Center, Harvard Medical; School,
       Southborough, Massachusetts 01772-9102.
 SO    J Virol. 1994 Sep;68(9):5933-44. Unique Identifier : AIDSLINE
       MED/94335111
 AB    The nef reading frame overlaps about 70% of the U3 region of the 3' long
       terminal repeat (LTR) in primate lentiviruses. We investigated the
       functional role of these overlapping U3 sequences by analyzing the
       properties of three mutant forms of the pathogenic SIVmac239 clone. In
       mutant UScon, 90 of 275 bp in the upstream sequences (US) of U3 were
       changed in a conservative fashion without changing the predicted nef
       coding sequence. In mutant USnon, 101 of 275 bp in this region were
       changed in a nonconservative fashion, again without changing the
       predicted nef coding sequence. In mutant delta US, 275 bp in this region
       were deleted. Full-size, immunoreactive nef protein was synthesized in
       cells infected with the UScon and USnon mutants. The USnon and delta US
       mutants replicated with similar kinetics and to similar extents as
       wild-type, parental SIVmac239 in primary rhesus monkey peripheral blood
       mononuclear cell (PBMC) cultures. The UScon mutant replicated with
       slightly delayed kinetics in rhesus monkey PBMC cultures. In the CEMx174
       cell line, the delta US mutant replicated similarly to the wild type,
       but the UScon and USnon mutants replicated with significantly delayed
       kinetics. Analysis of LTR-driven chloramphenicol acetyltransferase (CAT)
       activity and the effects of 5-azacytidine on virus replication suggested
       that the growth defect of the point mutants in CEMx174 cells was due in
       whole or in part to the introduction of multiple CG methylation sites in
       proviral DNA. Rhesus monkeys were experimentally infected with the UScon
       and USnon mutants, and the characteristics of the infection were
       compared with those of the parental SIVmac239. Analysis of the levels of
       plasma antigenemia, virus load, and CD4+ cells in PBMC revealed no
       decreased virulence of the mutant viruses. Analysis of lymph node
       biopsies taken from animals that received mutant viruses revealed
       histologic changes and levels of virus expression indistinguishable from
       those of the wild type. Furthermore, the wild-type behavior of the
       mutant viruses in rhesus monkeys occurred without any specific
       reversional events through at least 20 weeks of infection. These
       results, and the recent results of Kirchhoff et al. (F. Kirchoff, H. W.
       Kestler III, and R. C. Desrosiers, J. Virol. 68:2031-2037, 1994),
       suggest that these upstream sequences in U3 are primarily or exclusively
       nef coding sequence.
 DE    Amino Acid Sequence  Animal  Base Sequence  Comparative Study  DNA
       Primers/CHEMISTRY  Gene Expression Regulation, Viral  Gene Products,
       nef/METABOLISM  Genes, nef  Leukocyte Count  Lymph Nodes/MICROBIOLOGY
       Macaca mulatta  Methylation  Molecular Sequence Data  Repetitive
       Sequences, Nucleic Acid  RNA, Messenger/GENETICS  Sequence Alignment
       Sequence Homology, Nucleic Acid  Simian Acquired Immunodeficiency
       Syndrome/*MICROBIOLOGY  Support, U.S. Gov't, P.H.S.  SIV/*PATHOGENICITY
       T4 Lymphocytes  Virus Replication  JOURNAL ARTICLE

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