MiR-125b regulates the differentiation of hair follicles in Fine-wool Sheep and Cashmere goats by targeting MXD4 and FGFR2.

With the development of miRNAs identification technology, more and more miRNAs have been discovered, and the role of miRNAs in the development of animal hair follicles has become a focus of research on hair-producing animals. In the previous experiment, compare the microRNA (miRNA) trancriptomes of goats and sheep skin using Solexa sequencing and differentially expressed miR-125b was screened. However, the mechanism of miR-125b regulating hair follicle development is not clear. Therefore, in the present study, the expression of miR-125b, MXD4 and FGFR2 in skin tissue of Fine-wool Sheep and Cashmere goats and HEK-293T cells was examined by qPCR and Western blot. Furthermore, the correlation between miR-125b and the predicted target gene (MXD4, FGFR2) was verified using the Dual-luciferase Reporter assay. We demonstrated that the expression of MXD4 and FGFR2 in Cashmere goats was significantly higher than that of Fine-wool Sheep, and the expression was opposite to that of miR-125b. miR-125b can down-regulate the levels of MXD4 and FGFR2. Dual-luciferase reporter gene assay showed that miR-125b could bind to the 3'-UTR region of target genes FGFR2 and MXD4, suggesting that MXD4 and FGFR2 were target genes of miR-125b. This study has shown that the growth and development of hair follicles in skin tissue of Fine-wool Sheep and Cashmere goats from the new regulatory levels of miRNAs, and clarified the mechanism of miR-125b and its target genes in the development of hair follicles in the skin.