Previous Article | Next Article ![]()
J. Virol., 02 1995, 1150-1159, Vol 69, No. 2
MS Hansen and E Barklis
We have examined structural interactions between Gag proteins within
Moloney murine leukemia virus (M-MuLV) particles by making use of the
cysteine-specific cross-linking agents iodine and bis-maleimido hexane.
Virion-associated wild-type M-MuLV Pr65Gag proteins in immature particles
were intermolecularly cross-linked at cysteines to form Pr65Gag oligomers,
from dimers to pentamers or hexamers. Following a systematic approach of
cysteine-to-serine mutagenesis, we have shown that cross-linking of Pr65Gag
occurred at cysteines of the nucleocapsid (NC) Cys-His motif, suggesting
that the Cys-His motifs within virus particles are packed in close
proximity. The M-MuLV Pr65Gag protein did not cross-link to the human
immunodeficiency virus Pr55Gag protein when the two molecules were
coexpressed, indicating either that they did not coassemble or that
heterologous Gag proteins were not in close enough proximity to be
cross-linked. Using an assembly-competent, protease- minus, cysteine-minus
Pr65Gag protein as a template, novel cysteine residues were generated in
the M-MuLV capsid domain major homology region (MHR). Cross-linking of
proteins containing MHR cysteines showed above-background levels of Gag-Gag
dimers but also identified a novel cellular factor, present in virions,
that cross-linked to MHR residues. Although the NC cysteine mutation was
compatible with M-MuLV particle assembly, deletions of the NC domain were
not tolerated. These results suggest that the Cys-His motif is held in
close proximity within immature M-MuLV particles by interactions between CA
domains and/or non- Cys-His motif domains of the NC.
Copyright © 1995, American Society for Microbiology
Structural interactions between retroviral Gag proteins examined by cysteine cross-linking
Vollum Institute for Advanced Biomedical Research, Oregon Health Sciences University, Portland 97201-3098.
This article has been cited by other articles:
Copyright © 2009 by the American Society for Microbiology. For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»