Transcriptome identification and characterization of long non-coding RNAs in the ovary of hens at four stages.

Long non-coding RNAs (lncRNAs) play important roles in transcriptional and post-transcriptional regulation. LncRNAs, which are defined as non-coding RNAs more than 200 bp in length, are involved in key biological processes, such as cell proliferation and differentiation, epigenetic regulation, and gene transcriptional translation. Recent studies have shown that lncRNAs also play major regulatory roles in the reproduction of mammals. However, knowledge of the roles of lncRNAs in the chicken ovary lacking. In this study, we performed RNA-seq analyses of ovarian tissue from Hy-Line brown laying hens at four physiological stages [15, 20, 30, and 68 weeks of age (W)]. We identified 657 lncRNA transcripts that were differentially expressed during ovarian development, the number of down-regulated lncRNAs was higher than the number of up-regulated lncRNAs during development. We predicted the cis and trans target genes of the DE lncRNAs and constructed a lncRNA-mRNA interaction network, which indicated that the DE genes (DEGs) and the target genes of the DE lncRNAs are mainly involved in signaling pathways associated with ovarian development, including oocyte meiosis, calcium signaling pathways, ECM-receptor interactions, and ribosome and focal adhesion. Overall, we found that twelve lncRNAs were strongly involved in ovarian development: LNC_013443, LNC_001029, LNC_005713, LNC_016762, ENSGALT00000101857, LNC_003913, LNC_013692, LNC_012219, LNC_004140, ENSGALT00000096941, LNC_009356, and ENSGALT00000098716. In summary, our study utilized RNA-seq analysis of hen ovaries to explore key lncRNAs involved in ovarian development and function. Furthermore, the comprehensive analysis identified the target genes of these lncRNAs providing a better understanding of the mechanisms underlying ovarian development in hens and a theoretical basis for further research.