Mouse melanocortin-4 receptor gene 5′-flanking region imparts cell specific expression in vitro

Weight homeostasis is exquisitely sensitive to changes in the abundance of melanocortin-4 receptor (MC4-R). To begin to understand the factors that regulate MC4-R gene expression, we determined there are no introns in the gene. there are multiple starts of transcription. and a cluster of 3' ends. A series of MC4-R-luciferase gene reporter chimerics was developed and transfected into cell lines expressing (UMR106: GT1-7; HEK293) and not expressing (Neuro 2A) endogenous MC4-R mRNA. The longest construct, which includes approximate to3.3 kb 5'-flanking, 425 bp 5'-untranslated (UTR) and 1852 bp 3'-flanking, significantly increased luciferase reporter gene expression 24- 13-. and 3-fold compared to pGL3-basic when expressed in HEK293, UMR106, and GT1-7 cells, respectively. Deletion analysis of mMC4-R 5'-flanking cDNA identified full mMC4-R promoter activity within 178 bp upstream of the major start of transcription. The mMC4-R gene structure and reporter chimerics provide a fundamental framework for the identification of specific factors regulating MC4-R gene expression. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.