Screening And Identification Of MicroRNAs Related To Fetal Skin Melanogenesis In Goat

MicroRNAs (miRNAs) have been described to be involved in the pigmentation process. However, little is known about the expression profiles of miRNAs in fetal skin which may control the early states of pigmentation. To better understand the role of miRNAs in control of skin color, three small RNA libraries from 100-day old black fetal skins and three of these from 100-day old white fetal skins were sequenced by Illumina sequencing technology respectively.1. A total of 317 sequences were revealed distinct miRNAs. Out of these 317miRNAs,187 were found to be reported in miRBase 20.0 for capra hircus and ovis aries,60 were homology with other mammalian miRNA, and 70 were completely new.2. Of these unique miRNAs,31 were showing markedly greater abundance in black fetal skin, and 31 were more abundantly expressed in white fetal skin. Ten out of 62 differentially expressed miRNAs were randomly selected for Q-PCR and the expression pattern was consistent with the deep sequencing results.3. A total of 86 genes targeted by the differentially expressed miRNAs wereinvolved in the melanogenesis. Remarkably, a 7-fold downregulation of miR-381 in black fetal skin was detected. Conserved binding sites for miR-381, miR-543, miR-129 in the MITF 3’UTR sequence were revealed by sequence analysis; Conserved binding sites for miR-544,miR-129 in the TYR 3’UTR sequence were revealed by sequence analysis. Moreover, a luciferase reporter assay demonstrated targeting of MITF by miR-381,miR-543 and miR-129 in HEK 293 cells and targeting of TYR by miR-544 and miR-129 in HEK 293 cells.This study represented the comprehensive survey of miRNAs expressed in fetal skin of goat with different skin colors and the results suggested important potential functions of miRNAs in early skin color regulation.