| First Author | Liang Y | Year | 1996 |
| Journal | J Neurochem | Volume | 67 |
| Issue | 4 | Pages | 1352-9 |
| PubMed ID | 8858915 | Mgi Jnum | J:36371 |
| Mgi Id | MGI:83804 | Doi | 10.1046/j.1471-4159.1996.67041352.x |
| Citation | Liang Y, et al. (1996) Identification of an octamer-1 transcription factor binding site in the promoter of the mouse mu-opioid receptor gene. J Neurochem 67(4):1352-9 |
| abstractText | In a previous study we showed that a region from -182 to +10 bp in the mouse mu-opioid receptor (MOR) promoter exhibited strong promoter activity. To identify protein-DNA interactions in this fragment, gel shift and DNase I footprint analyses were performed using nuclear extracts from mouse brain and the human neuroblastoma cell line, SK-N-SH. Two regions, nucleotide (nt) -121 to -100 and nt -42 to -22, were identified as being specific protein binding sites. The protein-DNA interaction in the nt -42 to -22 region was characterized in detail in this study. Methylation interference analysis of this region showed that nuclear protein from SK-N-SH cells contracted nucleotides within the sequence ATG-CAAAT, which is a binding motif for octamer trans-acting factors. An octamer-1 (Oct-1)-specific antibody super-shifted the protein-DNA complex in a gel shift assay. A UV cross-linking experiment showed that a nuclear protein, whose molecular weight is similar to that of the Oct-1 factor, bound to the octamer element in the nt -42 to -22 region. Mutagenesis of four base pairs within the octamer cis-acting element eliminated the specific protein binding in vitro. When the MOR-luciferase reporter construct (-182 to +10 bp) with the same four base pairs mutated was transiently transfected into SK-N-SH cells, a 200% increase in transcriptional activity was observed. Collectively, these data suggest that Oct-1 is binding to the octamer motif in the MOR gene and negatively modulating MOR gene expression. |
