Comparative genomic approach reveals novel conserved microRNAs in Inner Mongolia cashmere goat skin and longissimus dorsi.

MicroRNA (miRNA) is a large class of non-coding RNA which usually acts a fine-tuned regulation in repressing gene expression on transcriptional and post-transcriptional level during ontogenetic development, metabolism, and occurrence of disease. Due to the lateness of goat genome investigation, registered goat microRNAs are little known and the function of it is poorly understood. In this study, we identified 5 novel miRNAs express in cashmere goat skin and longissimus dorsi using comparative genomic approach combined with expression profile analysis. Further qPCR and sequencing validation demonstrated that the novel miRNAs we identified expressed in goat skin and longissimus dorsi, three of them with the highest expression in February and two in October, indicating these novel microRNAs were involved in growth and cessation of goat hair production. Subsequently, potential target genes were explored via base-pairing with complementary sequences miRNA/mRNA interaction searching. WDR12 and CSNK1A1 involved in Notch/Wnt signal transduction pathway were finally identified. Collectively, the approach of comparative genomics combining expression profile analysis is a powerful tool to identify novel miRNA in goat and the 5 identified novel miRNAs(chi-miR-2284n, chi-miR-421*, chi-miR-421, chi-miR-1839 and chi-miR-374; Accession number: JQ002550-JQ002554) play a essential role in goat hair production of cashmere goat, both in entering growth and cessation phase. This study is also a meaningful complement to the present goat miRNA database for further understanding function of miRNAs in regulation of goat cashmere production.