Molecular cloning of a bovine MSH receptor which is highly expressed in the testis.

A novel G protein-coupled receptor (BDF3) was isolated from bovine genomic DNA by a combined approach of polymerase chain reaction (PCR) and hybridization techniques. The predicted amino acid sequence is 317 amino acids in length and displays 80% homology to the human alpha-MSH receptor MC1. Stably transfected into CHO-K1 cells, BDF3 mediates an increase of intracellular cAMP-levels following incubation with NLE-alpha-MSH, a potent alpha-MSH analog. The stimulation with ACTH1-10 is only moderate and gamma-MSH is ineffective. Northern blot analysis of bovine tissues revealed that the BDF3 gene is highly expressed in the testis as a single 2.3 kb mRNA species, suggesting an involvement of the BDF3 receptor in spermatogenesis.