Volume 270,
Number 23,
Issue of June 9, pp. 13637-13644, 1995
©1995 by The American Society for Biochemistry and Molecular Biology, Inc.
The
Moloney Leukemia Retroviral Long Terminal Repeat
trans-Activates AP-1-inducible Genes and AP-1 Transcription
Factor Binding
Haiqin
Weng
,
Sang-Yun
Choi
,
Douglas V.
Faller
Moloney murine leukemia virus (Mo-MuLV) is a thymotropic and
leukemogenic retrovirus which causes T lymphomas. The long terminal
repeat (LTR) of Mo-MuLV affects the regulation of a number of cellular
genes, including collagenase IV, monocyte chemoattractant protein-1,
and c-jun genes, all of which contain
12-O-tetradecanoylphorbol-13-acetate-responsive ele-ment
consensus sites within their promoters. We report here that Mo-MuLV
stimulates the collagenase IV gene through transcription factor AP-1,
and that the expression of a subgenomic portion of Mo-MuLV LTR alone is
sufficient for this effect. Transient or stable expression of the viral
LTR increases cellular AP-1 DNA binding activity. The collagenase IV
12-O-tetradecanoylphorbol-13-acetate-responsive element
consensus sequence was shown to be required for this
trans-activation. Deletions or mutations of this consensus
site which abolished AP-1 binding also abolished
trans-activation by the LTR. Transient or stable transfection
of the viral LTR into cells stimulated c-jun gene expression,
suggesting one mechanism whereby the viral LTR may induce cellular AP-1
activity. Thus, the Mo-MuLV LTR, through activation of the
transcription factor AP-1, is capable of regulating cellular gene
expression, including the induction of proto-oncogenes. This activity
may be relevant to the mechanisms whereby retroviruses which do not
contain oncogenes induce neoplasia.