Ssc-miR-221-3p regulates melanin production in Xiang pigs melanocytes by targeting the TYRP1 gene

Abstract

Abstract Background: MicroRNAs (miRNAs) are small non-coding RNAs of endogenous origin that down-regulate gene expression. An increasing number of studies have confirmed that miRNAs play an important role in mammalian hair color production, and the TYRP1 gene, a member of the tyrosine family, is also an important candidate gene affecting melanogenesis. The aim of this study was to screen genes and miRNAs that affect melanin in Xiang pigs by transcriptome sequencing, and to validate through experiments whether the screened genes and miRNAs have a targeted regulatory relationship with each other and whether they can jointly affect melanin production in Xiang pigs. Results: 17 miRNAs and 1230 genes were significantly differentially expressed in the black and white skin tissues of Xiang pigs（P< 0.05）, based on which the candidate miRNA-221-3p for melanin formation and its target gene TYRP1 were screened. TYRP1 gene, as a member of the TYR gene family, was evolved from the TYR gene through chromosome segmental duplication, and the gene function was highly conserved throughout the evolutionary process. overexpression of TYRP1 gene significantly increased the expression of TYR, TYRP1 and DCT genes（P< 0.01）, which in turn increased the relative content of melanin, and TYRP1-siRNA significantly decreased the expression of TYR, TYRP1, and DCT genes in Xiang pig melanocytes（P< 0.01）, which in turn decreased the relative melanin content. Validation of the targeted binding relationship between ssc-miR-221-3p and TYRP1 gene, after transfection of porcine melanocytes with ssc-miR-221-3p mimic, the expression of ssc-miR-221-3p was significantly up-regulated（P < 0.01）, TYR, TYRP1, and DCT genes were significantly down-regulated at both mRNA and protein levels（P< 0.01）, and melanin content in cells was significantly reduced（P < 0.01）. Conclusion: The TYRP1 gene can affect melanogenesis in melanocytes of the Xiang pigs, and ssc-miR-221-3p targets the TYRP1 gene to affect melanogenesis in melanocytes of the Xiang pigs.