A novel mechanism of repression of the vascular endothelial growth factor promoter, by single strand DNA binding cold shock domain (Y-box) proteins in normoxic fibroblasts.
Overexpression of vascular endothelial growth factor (VEGF) is implicated in a number of diseases. It is therefore critical that mechanisms exist to strictly regulate VEGF expression. A hypoxia-responsive (HR) region of the VEGF promoter which binds the HIF-1 transcription factor is a target for many signals that up-regulate VEGF transcription. Repressors targeting the HIF-1 transcription factor have been identified but no repressors directly binding the HR promoter region had been reported. We now report a novel mechanism of repression of the VEGF HR region involving DNA binding. We find that single strand DNA-specific cold shock domain (CSD or Y-box) proteins repress the HR region via a binding site downstream of the HIF-1 site. The repressor site is functional in unstimulated, normoxic fibroblasts and represents a novel means to prevent expression of VEGF in the absence of appropriate stimuli. We characterized complexes forming on the VEGF repressor site and identified a previously unreported nuclear CSD protein complex containing dbpA. Nuclear dbpA appears to bind as a dimer and we determined a means by which nuclear CSD proteins may enter double strand DNA to bind to their single strand sites to bring about repression of the VEGF HR region.
Coles
Leeanne S
LS
Division of Human Immunology, The Hanson Centre for Cancer Research, Institute of Medical and Veterinary Science, Frome Road, Adelaide, SA 5000, Australia. leeanne.coles@imvs.sa.gov.au
Diamond
Peter
P
Lambrusco
Lidia
L
Hunter
Julie
J
Burrows
Julie
J
Vadas
Mathew A
MA
Goodall
Gregory J
GJ
D016475:3T3 Cells; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D022762:CCAAT-Enhancer-Binding Proteins / Q000378:metabolism; D015687:Cell Hypoxia; D002467:Cell Nucleus / Q000378:metabolism; D004277:DNA, Single-Stranded / Q000378:metabolism; D004278:DNA, Superhelical / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism*; D019281:Dimerization; D016228:Endothelial Growth Factors / Q000096:biosynthesis / Q000235:genetics*; D005347:Fibroblasts / Q000378:metabolism; D020868:Gene Silencing; D006360:Heat-Shock Proteins / Q000378:metabolism*; D036341:Intercellular Signaling Peptides and Proteins / Q000096:biosynthesis / Q000235:genetics*; D008222:Lymphokines / Q000096:biosynthesis / Q000235:genetics*; D046911:Macromolecular Substances; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D051839:NFI Transcription Factors; D011401:Promoter Regions, Genetic; D012097:Repressor Proteins / Q000378:metabolism*; D037941:Silencer Elements, Transcriptional; D014157:Transcription Factors; D015533:Transcriptional Activation; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors
D022762:CCAAT-Enhancer-Binding Proteins; C408323:Csda protein, mouse; D004277:DNA, Single-Stranded; D004278:DNA, Superhelical; D004268:DNA-Binding Proteins; D016228:Endothelial Growth Factors; D006360:Heat-Shock Proteins; D036341:Intercellular Signaling Peptides and Proteins; D008222:Lymphokines; D046911:Macromolecular Substances; D051839:NFI Transcription Factors; D012097:Repressor Proteins; D014157:Transcription Factors; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors