MC1RGen

MC1RGen is a fictional gene used in genetics education and in illustrative research to explore the regulation of pigmentation through the melanocortin-1 receptor (MC1R) pathway. In the hypothetical genome, MC1RGen is proposed to encode a transmembrane protein that interacts with MC1R or its downstream signaling components, modulating melanocyte activity and melanin synthesis.

Structural features and function: The predicted protein has seven transmembrane domains, consistent with GPCR-like topology, with extracellular N terminus and cytoplasmic C terminus. It is thought to influence cAMP signaling and MITF activation, thereby shifting the balance between eumelanin and pheomelanin in melanocytes. MC1RGen may act as a co-receptor, trafficking factor, or allosteric modulator of MC1R.

Expression and regulation: MC1RGen expression is described in melanocytes of skin and hair follicles, with upregulation following UV exposure and hormonal cues such as MSH analogs, mirroring MC1R regulation. In the educational model, variants of MC1RGen affect pigment intensity and color.

Genetic variation and model systems: In simulated populations, loss-of-function variants in MC1RGen reduce eumelanin production and increase pheomelanin, producing lighter phenotypes; gain-of-function variants may enhance tanning responses. Experimental approaches include cell culture assays and transgenic organisms in teaching simulations.

Significance: MC1RGen serves as a pedagogical tool to illustrate gene interactions in pigment biology and GPCR signaling, and to discuss epistasis with MC1R and other pigmentation genes.