Cold shock domain proteins repress transcription from the GM-CSF promoter.
The human granulocyte-macrophage colony stimulating factor (GM-CSF) gene promoter binds a sequence-specific single-strand DNA binding protein termed NF-GMb. We previously demonstrated that the NF-GMb binding sites were required for repression of tumor necrosis factor-alpha (TNF-alpha) induction of the proximal GM-CSF promoter sequences in fibroblasts. We now describe the isolation of two different cDNA clones that encode cold shock domain (CSD) proteins with NF-GMb binding characteristics. One is identical to the previously reported CSD protein dbpB and the other is a previously unreported variant of the dbpA CSD factor. This is the first report of CSD factors binding to a cytokine gene. Nuclear NF-GMb and expressed CSD proteins have the same binding specificity for the GM-CSF promoter and other CSD binding sites. We present evidence that CSD factors are components of the nuclear NF-GMb complex. We also demonstrate that overexpression of the CSD proteins leads to complete repression of the proximal GM-CSF promoter containing the NF-GMb/CSD binding sites. Surprisingly, we show that CSD overexpression can also directly repress a region of the promoter which apparently lacks NF-GMb/CSD binding sites. NF-GMb/CSD factors may hence be acting by two different mechanisms. We discuss the potential importance of CSD factors in maintaining strict regulation of the GM-CSF gene.
Coles
L S
LS
Division of Human Immunology, Hanson Centre for Cancer Research, Institute of Medical and Veterinary Science, Adelaide, South Australia, Australia.
Diamond
P
P
Occhiodoro
F
F
Vadas
M A
MA
Shannon
M F
MF
D000595:Amino Acid Sequence; D001483:Base Sequence; D022762:CCAAT-Enhancer-Binding Proteins; D002352:Carrier Proteins; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism; D003001:Cloning, Molecular; D003080:Cold Temperature; D018076:DNA, Complementary; D004277:DNA, Single-Stranded / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D015870:Gene Expression; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000235:genetics*; D006360:Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic; D014407:Tumor Cells, Cultured
D022762:CCAAT-Enhancer-Binding Proteins; D002352:Carrier Proteins; D018076:DNA, Complementary; D004277:DNA, Single-Stranded; D004268:DNA-Binding Proteins; D006360:Heat-Shock Proteins; D012097:Repressor Proteins; C094867:YBX3 protein, human; D016178:Granulocyte-Macrophage Colony-Stimulating Factor