The G10BP-1 gene encoding a GC box binding protein, is a target of Myc and Jun/Fos.
BACKGROUND
G10BP, a serum-inducible factor, represses the transcription of the fibronectin gene through binding to the G-rich sequences in the promoter excluding Sp1 from binding to these sequences.


RESULTS
The 5' flanking sequence of the G10BP-1 gene was isolated by polymerase chain reaction of the adaptor-ligated genomic DNA library using the adaptor primer and the G10BP-1 cDNA primer. The elements required for activation of the G10BP-1 promoter following serum stimulation were analysed by transfection of quiescent rat 3Y1 cells with G10BP-1 promoter-luciferase cDNA constructs containing 5' sequential deletions or base substitutions. The results showed that the promoter was activated by Myc and Jun through the E box and AP1 sites. The formation of DNA-protein complexes with 32P-labelled oligonucleotides containing the E box or AP1 site with cell extracts prepared during G1 progression was correlated with the promoter activation and greatly reduced by immunodepletion of Myc or c-Jun from the extracts.


CONCLUSIONS
These results indicate that the G10BP-1 gene is a target of Myc and Jun/Fos and that these factors repress the fibronectin gene expression through induction of G10BP-1 during G1-to-S phase progression.
Department of Biological Science and Technology, Science University of Tokyo, 2641 Yamazaki, Noda 278, Japan.
K
K
Shirasuna
A
A
Takeuchi
T
T
Bando
T
T
Nakajima
K
K
Oda
D000818:Animals; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D018797:Cell Cycle Proteins; D002460:Cell Line; D003001:Cloning, Molecular; D004247:DNA / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D016193:G1 Phase; D005786:Gene Expression Regulation; D008156:Luciferases / Q000235:genetics; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic / Q000235:genetics; D011485:Protein Binding; D016755:Proto-Oncogene Proteins c-jun / Q000378:metabolism*; D016271:Proto-Oncogene Proteins c-myc / Q000378:metabolism*; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000235:genetics; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D016196:S Phase; D017384:Sequence Deletion
D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; C113768:G10BP-1 protein, rat; C072278:GCFC2 protein, human; D046911:Macromolecular Substances; D016755:Proto-Oncogene Proteins c-jun; D016271:Proto-Oncogene Proteins c-myc; D011993:Recombinant Fusion Proteins; D012097:Repressor Proteins; D004247:DNA; D008156:Luciferases