Identification of microRNAs in Wool Follicles During Anagen, Catagen and Telogen Phases in the Sheep

The wool quality is one of the most important economic traits in the sheep. The wool fiber is derived from the specialized skin cells that called wool follicles. In order to understand the roles of microRNAs in wool fiber growth, we detected the expression patterns of microRNAs in wool follicles at anagen, catagen and telogen stages. In this study, 244 mature miRNAs were identified. Among them, only 5 miRNAs have been submitted to the miRNAs database of sheep and the other 239 miRNAs were first reported. Further analysis indicated that 204 miRNAs were conserved among mammal species and the other 35 miRNAs were identified specifically in sheep (miRBase Database V19). Expression pattern analysis showed that 39 miRNAs were significantly changed between anagen and catagen, 34 miRNAs changed between anagen and telogen, and 20 miRNAs changed between catagen and telogen. Functional analysis results showed that 6 different expressed microRNAs could target the key genes of Wnt pathway. It has been reported that Wnt pathway was critical for wool follicles development. Therefore, these microRNAs may regulated wool development through Wnt pathway. Taken together, our results added new information to the microRNA identification and the expression in wool follicles; These would be useful for understanding of the development of wool follicle of sheep.