Expression and network analysis of genes related to melanocyte development in the Silky Fowl and White Leghorn embryos

Silky Fowl is a natural mutant with hyperpigmentation of various internal tissues. Although the mechanism of hyperpigmentation remains unclear, recent studies have shown that the abnormal migration of melanoblast and the absence of environmental barrier molecules are responsible for the hyperpigmentation in Silky Fowl. In this study, 13 genes related to melanocyte development were selected to detect expression changes between Silky Fowl and White Leghorn [including SRY-box 10 (Sox10), paired box (Pax3), stem cell factor (Scf), v-kit Hardy-Zuckerman 4 feline sarcoma viral oncogene homolog (Kit), endothelin type-B receptor (Ednrb), endothelin 3 (Edn3), microphthalmia-associated transcription factor (Mitf), tyrosinase (Tyr), tyrosinase-related protein-1 (Trp1), tyrosinase-related protein-2 (Trp2), melanocortin-1 receptor (Mc1r), Agouti-related proteins (Agrp), and Proopiomelanocortin (Pomc)]. Transcript expression was detected in 11 stages from 2.5 to 15 days of incubation. In these embryonic periods, Mitf, Kit, Scf, and Agrp expressed earlier in Silky Fowl than in White Leghorn. Sox10, Ednrb, Kit, Mc1r, and Agrp, associating with the proliferation and differentiation of melanoblast, expressed higher (P < 0.05) in Silky Fowl than White Leghorn during 5-6 days of incubation. After day 8 of incubation, Mitf, Tyr, Trp1, Trp2, and Mc1r expressed higher (P < 0.05) in Silky Fowl than White Leghorn, while Agrp expressed higher (P < 0.05) in White Leghorn than Silky Fowl. Moreover, a regulatory network for melanocyte development was constructed based on the expression data. The network predicted novel regulatory relationships and confirmed relationships that have been reported. These results provide biological insight into the molecular mechanism of hyperpigmentation in the Silky Fowl. However, further investigation is needed to confirm these regulatory relationships.