       Document 0103
 DOCN  M9630103
 TI    Single amino acid substitution in constant region 1 or 4 of gp120 causes
       the phenotype of a human immunodeficiency virus type 1 variant with
       mutations in hypervariable regions 1 and 2 to revert.
 DT    9603
 AU    Wang WK; Essex M; Lee TH; Department of Cancer Biology, Harvard School
       of Public Health,; Boston, Massachusetts 02115, USA.
 SO    J Virol. 1996 Jan;70(1):607-11. Unique Identifier : AIDSLINE
       MED/96099479
 AB    The second major cysteine loop of human immunodeficiency virus type 1
       envelope glycoprotein gp120 contains 5 to 11 consensus N-linked
       glycosylation sites, which is disproportionately higher than the number
       of such sites found in other regions of gp120. Amino acid substitutions
       introduced at three of six N-linked glycosylation sites in this region
       of an infectious molecular clone, HXB2, resulted in severe impairment of
       virus infectivity. Isolation and genetic characterization of a revertant
       of this mutant revealed an isoleucine-for-valine substitution at
       position 84 in constant region 1 and an isoleucine-for-methionine
       substitution at position 434 in constant region 4. Further mutational
       analysis indicated that either isoleucine substitution was sufficient to
       confer the revertant phenotype. These findings demonstrate that V1/V2
       not only functionally interacts with C4, as previously reported, but
       also interacts with C1. The observation that compensatory changes do not
       involve regeneration of N-linked glycosylation sites in the second major
       cysteine loop suggests that replication of human immunodeficiency virus
       type 1 in vitro is independent of the presence of a disproportionate
       number of N-linked glycosylation sites within this loop.
 DE    Amino Acid Sequence  Animal  Base Sequence  Binding Sites  Cell Line
       Cloning, Molecular  DNA Primers  Glycosylation  Human  HIV Envelope
       Protein gp120/*GENETICS/METABOLISM  HIV-1/*GENETICS/METABOLISM
       Molecular Sequence Data  Mutagenesis, Site-Directed  *Mutation
       Phenotype  Support, U.S. Gov't, Non-P.H.S.  Support, U.S. Gov't, P.H.S.
       Variation (Genetics)  JOURNAL ARTICLE

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

