Expression and localization of GPR143 in sheep skin.

G-protein coupled receptor143 (GPR143) plays an important role in melanogenesis. In this study, we investigated the expression pattern and localization of GPR143 in skin of sheep with different coat colors and explored the correlation between GPR143 gene and coat color. The mRNA level and protein level of GPR143 in skin of sheep with different coat colors were detected by qRT-PCR and immunoblotting separately while the localization of GPR143 in sheep skin was detected by immunofluorescence assay following optical density analysis. The qRT-PCR results showed that the relative expression level of GPR143 mRNA in black sheep skin was 7.84 times of that in white sheep skin (P<0.01). Immunoblotting results demonstrated that the expression level of GPR143 protein in black sheep skin was 1.30 times of that in white sheep skin (P<0.05). Immunofluorescence assay revealed that GPR143 was primarily expressed in the outer root sheath of hair follicles and epidermal skin tissue. Optical density analysis showed that expression levels of GPR143 in the outer root sheath and epidermis of black sheep skin were significantly higher than that of white sheep skin. Our studies demonstrated that GPR143 is expressed in skin of sheep with different coat colors. However, the mRNA and protein levels of GPR143 in black sheep skin are significantly higher than that in white sheep skin, indicating that GPR143 mRNA and protein levels are upregulated in skin of black sheep while downregulated in skin of white sheep. GPR143 may participate in the formation of coat color by regulating the level of MITF and the number, size, motility and maturation of the melanosome.