Platelet-derived growth factor induction of the immediate-early gene MCP-1 is mediated by NF-kappaB and a 90-kDa phosphoprotein coactivator.
A broad panel of agents including serum, interleukin-1, double-stranded RNA, and platelet-derived growth factor (PDGF) stimulate transcription of the "slow" immediate-early gene MCP-1. These disparate inducers act through a tight cluster of regulatory elements in the distal 5'-flanking sequences of the MCP-1 gene. We describe a 22-base element in this cluster which, in single copy, confers PDGF-inducibility to a tagged MCP-1 reporter gene. In mobility shift assays, the element binds a PDGF-activated form of NF-kappaB, and a 90-kDa protein (p90) which binds constitutively. Antibody supershift and UV cross-linking experiments indicate that the PDGF-activated NF-kappaB species is a Rel A homodimer. The DNA binding form of p90 is a nuclear-restricted serine/threonine phosphoprotein. Mutagenesis of the 22-base element shows that the NF-kappaB and p90 binding sites overlap, but binding of the two species is mutually independent. Both sites, however, are required for optimum PDGF induction of MCP-1. Therefore, p90 appears to be a coactivator with NF-kappaB in PDGF-mediated induction of MCP-1.
Freter
R R
RR
Department of Microbiology, Harvard Medical School and the Dana-Farber Cancer Institute, Boston, Massachusetts 02115, USA.
Alberta
J A
JA
Hwang
G Y
GY
Wrentmore
A L
AL
Stiles
C D
CD
D016475:3T3 Cells; D000818:Animals; D001483:Base Sequence; D000077214:Becaplermin; D002467:Cell Nucleus / Q000378:metabolism; D018932:Chemokine CCL2 / Q000096:biosynthesis* / Q000235:genetics; D018983:DNA Footprinting; D004742:Enhancer Elements, Genetic; D005091:Exons; D015870:Gene Expression / Q000187:drug effects; D017781:Genes, Immediate-Early / Q000187:drug effects*; D051379:Mice; D008969:Molecular Sequence Data; D008970:Molecular Weight; D016297:Mutagenesis, Site-Directed; D016328:NF-kappa B / Q000096:biosynthesis / Q000378:metabolism*; D009838:Oligodeoxyribonucleotides; D010750:Phosphoproteins / Q000096:biosynthesis / Q000378:metabolism*; D010982:Platelet-Derived Growth Factor / Q000494:pharmacology*; D020574:Proto-Oncogene Proteins c-sis; D015347:RNA Probes; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000378:metabolism / Q000494:pharmacology; D014162:Transfection
D018932:Chemokine CCL2; D016328:NF-kappa B; D009838:Oligodeoxyribonucleotides; D010750:Phosphoproteins; D010982:Platelet-Derived Growth Factor; D020574:Proto-Oncogene Proteins c-sis; D015347:RNA Probes; D011994:Recombinant Proteins; D000077214:Becaplermin