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M9490407.TXT
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1994-09-19
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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).