Identification and Molecular Analysis of m 6 A-circRNAs from Cashmere Goat Reveal Their Integrated Regulatory Network and Putative Functions in Secondary Hair Follicle during Anagen Stage

-methyladenosine (m A) is the most abundant modification in linear RNA molecules. Over the last few years, interestingly, many circRNA molecules are also found to have extensive m A modification sites with temporal and spatial specific expression patterns. To date, however, little information is available concerning the expression profiling and functional regulatory characteristics of m A modified circRNAs (m A-circRNAs) in secondary hair follicles (SHFs) of cashmere goats. In this study, a total of fifteen m A-circRNAs were identified and characterized in the skin tissue of cashmere goats. Of these, six m A-circRNAs were revealed to have significantly higher expression in skin at anagen compared with those at telogen. The constructed ceRNA network indicated a complicated regulatory relationship of the six anagen up-regulated m A-circRNAs through miRNA mediated pathways. Several signaling pathways implicated in the physiological processes of hair follicles were enriched based on the potential regulatory genes of the six anagen up-regulated m A-circRNAs, such as TGF-beta, axon guidance, ribosome, and stem cell pluripotency regulatory pathways, suggesting the analyzed m A-circRNAs might be essentially involved in SHF development and cashmere growth in cashmere goats. Further, we showed that four m A-circRNAs had highly similar expression trends to their host genes in SHFs of cashmere goats including m A-circRNA-ZNF638, -TULP4, -DNAJB6, and -CAT. However, the expression patterns of two m A-circRNAs (m A-circRNA-STAM2 and -CAAP1) were inconsistent with the linear RNAs from their host genes in the SHFs of cashmere goats. These results provide novel information for eluci-dating the biological function and regulatory characteristics of the m A-circRNAs in SHF development and cashmere growth in goats.