| First Author | Hwang CS | Year | 1996 |
| Journal | Proc Natl Acad Sci U S A | Volume | 93 |
| Issue | 2 | Pages | 873-7 |
| PubMed ID | 8570651 | Mgi Jnum | J:31192 |
| Mgi Id | MGI:78676 | Doi | 10.1073/pnas.93.2.873 |
| Citation | Hwang CS, et al. (1996) Transcriptional activation of the mouse obese (ob) gene by CCAAT/enhancer binding protein alpha. Proc Natl Acad Sci U S A 93(2):873-7 |
| abstractText | Like other adipocyte genes that are transcriptionally activated by CCAAT/enhancer binding protein alpha (C/EBP alpha) during preadipocyte differentiation, expression of the mouse obese (ob) gene is immediately preceded by the expression of C/EBP alpha. While the 5' flanking region of the mouse ob gene contains several consensus C/EBP binding sites, only one of these sites appears to be functional. DNase I cleavage inhibition patterns (footprinting) of the ob gene promoter revealed that recombinant C/EBP alpha, as well as a nuclear factor present in fully differentiated 3T3-L1 adipocytes, but present at a much lower level in preadipocytes, protects the same region between nucleotides -58 and -42 relative to the transcriptional start site. Electrophoretic mobility-shift analysis using nuclear extracts from adipose tissue or 3T3-L1 adipocytes and an oligonucleotide probe corresponding to a consensus C/EBP binding site at nucleotides -55 to -47 generated a specific protein-oligonucleotide complex that was supershifted by antibody against C/EBP alpha. Probes corresponding to two upstream consensus C/EBP binding sites failed to generate protein-oligonucleotide complexes. Cotransfection of a C/EBP alpha expression vector into 3T3-L1 cells with a series of 5' truncated ob gene promoter constructs activated reporter gene expression with all constructs containing the proximal C/EBP binding site (nucleotides -55 to -47). Mutation of this site blocked transactivation by C/EBP alpha. Taken together, these findings implicate C/EBP alpha as a transcriptional activator of the ob gene promoter and identify the functional C/EBP binding site in the promoter. |
