The carbamyl phosphate synthetase promoter contains multiple binding sites for C/EBP-related proteins.
The promoter of the gene (CPS) encoding rat carbamyl phosphate synthetase I has been mapped 5' to a segment of about 525 nucleotides upstream from the transcription start point and, when analyzed in liver nuclear extracts, contained six well-defined protein-recognition elements, designated CPS sites I-VI. All six elements were recognized, with varying affinities, by CAAT and enhancer-binding protein (C/EBP alpha) produced in bacteria. Oligodeoxyribonucleotides corresponding to CPS site II or to the C/EBP alpha-recognition element of the ALB promoter, site D, competed with the six CPS-promoter elements in footprinting assays. However, mutagenesis of the C/EBP alpha-recognition element, 5'-GTTGCAAC, at the core of site II was sufficient to abolish transactivation of the CPS promoter by C/EBP alpha in co-transfected HepG2 cells. These findings indicate that the CPS promoter contains multiple recognition elements for factors with DNA-binding specificities similar to C/EBP proteins. Activation by C/EBP alpha, however, requires promoter site II.
Lagacé
M
M
Department of Biochemistry, McGill University, Montreal, Quebec, Canada.
Goping
I S
IS
Mueller
C R
CR
Lazzaro
M
M
Shore
G C
GC
D000818:Animals; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D022762:CCAAT-Enhancer-Binding Proteins; D002222:Carbamoyl-Phosphate Synthase (Ammonia) / Q000235:genetics*; D003001:Cloning, Molecular; D004268:DNA-Binding Proteins / Q000378:metabolism*; D008099:Liver / Q000201:enzymology*; D008969:Molecular Sequence Data; D016296:Mutagenesis / Q000235:genetics; D009687:Nuclear Proteins / Q000378:metabolism*; D009838:Oligodeoxyribonucleotides / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000235:genetics*; D051381:Rats; D014157:Transcription Factors / Q000378:metabolism*; D014407:Tumor Cells, Cultured
D022762:CCAAT-Enhancer-Binding Proteins; C485975:DBP protein, rat; D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D009838:Oligodeoxyribonucleotides; D014157:Transcription Factors; D002222:Carbamoyl-Phosphate Synthase (Ammonia)