Expression of mc4r in Developing Embryos and Larvae of Zebrafish

Severe obesity seen in human kindred bearing recessive, loss-of-function MC4R gene mutations is recapitulated by mice and rats bearing targeted and spontaneous loss-of-function alleles in orthologous Mc4r genes. These rodent models have revealed neural pathways in the hypothalamus regulating food intake and energy expenditure, with Mc4r signaling serving as major signal of satiety. Melanocortin 4 receptor is a central regulator of energy homeostasis and feeding and it is predominantly expressed in the brain. The lab I am working with has a Mc4r mutant and is performing various studies. Recently, few studies have suggested that melanocortin system is involved in regulation of peripheral lipid and glucose metabolism. In this subproject, we want to investigate the expression pattern of the mc4r in developing embryos and larvae of zebrafish.  We used whole mount in situ hybridization for this purpose. We designed three different riboprobes and using a PCR cloning kit, we cloned the probes. The riboprobes were then synthesized using the commercial kit. Standard protocol for whole mount in situ hybridization was followed and the results showed that mc4r is ubiquitously expressed with strong expression in brain. Further studies are required to determine the function of Mc4r in peripheral tissues.