Profiling and Functional Analysis of long non-coding RNAs in yak healthy and atretic follicles.

Yak is the livestock on which people live in plateau areas, but its fecundity is low. Follicular development plays a decisive role in yak reproductive performance. As an important regulatory factor, the expression of long non-coding RNA (lncRNAs) in yak follicular development and its regulatory mechanism remains unclear. To explore the differentially expressed lncRNAs between healthy and atretic follicular in yaks. We used RNA-seq to construct lncRNA, miRNA, and mRNA expression profiles in yak atretic and healthy follicles, and the RNA sequence results were identified by qPCR. In addition, the correlation of lncRNA and targeted mRNA was also analyzed by Starbase software. Moreover, lncRNA/miRNA/mRNA networks were constructed by Cytoscape software, and the network was verified by dual-luciferase analysis. A total of 682 novel lncRNAs, 259 bta-miRNAs, and 1704 mRNAs were identified as differentially expressed between healthy and atretic follicles. Among them, 135 mRNAs were positively correlated with lncRNA expression and 97 were negatively correlated, which may be involved in the yak follicular development. In addition, pathway enrichment analysis of differentially expressed lncRNA host genes by Kyoto Genome Encyclopedia (KEGG) showed that host genes were mainly involved in hormone secretion, granulosa cell apoptosis, and follicular development. In conclusion, we identified a series of novel lncRNAs, constructed the lncRNA ceRNA regulatory network, and provided comprehensive resources for exploring the role of lncRNAs in yak ovarian follicular development.