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1996-03-04
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Document 0662
DOCN M9640662
TI Evidence for a second function of the MA sequence in the Rous sarcoma
virus Gag protein.
DT 9604
AU Parent LJ; Wilson CB; Resh MD; Wills JW; Department of Medicine,
Pennsylvania State University College of; Medicine, Hershey 17033, USA.
SO J Virol. 1996 Feb;70(2):1016-26. Unique Identifier : AIDSLINE
MED/96135214
AB During retrovirus assembly, Gag proteins bind to the inner leaflet of
the plasma membrane to initiate the budding process. The molecular basis
of this protein-lipid interaction is poorly understood. For the human,
immunodeficiency virus type 1 Gag protein, we recently reported that the
membrane-binding domain resides within the N-terminal 31 amino acids and
consists of two components: myristate and a cluster of basic residues,
which together promote membrane binding in vitro and budding in vivo (W.
Zhou, L. J. Parent, J. W. Wills, and M. D. Resh, J. Virol. 68:2556-2569,
1994). The positively charged residues associate electrostatically with
acidic phospholipids to stabilize membrane binding, while myristate
provides membrane-binding energy via hydrophobic interactions. Here we
demonstrate that the human immunodeficiency virus type 1 Gag
membrane-binding domain can fully replace the membrane-targeting
function of the N-terminal 100 residues of the non-myristylated Rous
sarcoma virus (RSV) Gag protein. To further explore the importance of
myristate and basic residues in membrane binding, we developed a
gain-of-function assay whereby budding was restored to defective mutants
of RSV Gag. Detailed mutational analysis revealed that the position,
number, and context of charged residues are crucial to budding.
Myristate provides additional membrane-binding energy, which is critical
when a Gag protein is near the threshold of stable membrane association.
Finally, viruses with altered matrix (MA) proteins that are
noninfectious, even though they produce particles with high efficiency,
were identified. Thus, we present the first evidence that the RSV MA
sequence plays two distinct roles, membrane binding during particle
assembly and a second, as yet undefined function required for viral
infectivity.
DE Amino Acid Sequence Base Sequence Binding Sites DNA, Viral Gene
Products, gag/GENETICS/*PHYSIOLOGY Human HIV-1/GENETICS/*PHYSIOLOGY
Molecular Sequence Data Mutagenesis, Insertional Myristic
Acids/METABOLISM Sarcoma Viruses,
Avian/GENETICS/*PHYSIOLOGY/PATHOGENICITY Support, Non-U.S. Gov't
Support, U.S. Gov't, P.H.S. JOURNAL ARTICLE
SOURCE: National Library of Medicine. NOTICE: This material may be
protected by Copyright Law (Title 17, U.S.Code).