Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, Shandong Agricultural University, 61 Daizong Street, Tai'an 271018, China.
Biomolecules. 2023 May 18;13(5):860. doi: 10.3390/biom13050860.
This study conducted transcriptome sequencing of goat-mammary-gland tissue at the late lactation (LL), dry period (DP), and late gestation (LG) stages to reveal the expression characteristics and molecular functions of circRNAs during mammary involution. A total of 11,756 circRNAs were identified in this study, of which 2528 circRNAs were expressed in all three stages. The number of exonic circRNAs was the largest, and the least identified circRNAs were antisense circRNAs. circRNA source gene analysis found that 9282 circRNAs were derived from 3889 genes, and 127 circRNAs' source genes were unknown. Gene Ontology (GO) terms, such as histone modification, regulation of GTPase activity, and establishment or maintenance of cell polarity, were significantly enriched (FDR < 0.05), which indicates the functional diversity of circRNAs' source genes. A total of 218 differentially expressed circRNAs were identified during the non-lactation period. The number of specifically expressed circRNAs was the highest in the DP and the lowest in LL stages. These indicated temporal specificity of circRNA expression in mammary gland tissues at different developmental stages. In addition, this study also constructed circRNA-miRNA-mRNA competitive endogenous RNA (ceRNA) regulatory networks related to mammary development, immunity, substance metabolism, and apoptosis. These findings help understand the regulatory role of circRNAs in mammary cell involution and remodeling.
本研究对泌乳后期（LL）、干奶期（DP）和妊娠后期（LG）的山羊乳腺组织进行了转录组测序，以揭示乳腺退化过程中 circRNAs 的表达特征和分子功能。本研究共鉴定出 11756 个 circRNAs，其中 2528 个在三个阶段均有表达。外显子 circRNAs 的数量最多，而反义 circRNAs 的数量最少。circRNA 来源基因分析发现，9282 个 circRNAs 来源于 3889 个基因，127 个 circRNAs 的来源基因未知。GO 功能富集分析发现，circRNA 来源基因参与了组蛋白修饰、GTP 酶活性调节、细胞极性建立或维持等生物学过程（FDR<0.05），表明 circRNA 来源基因具有功能多样性。在非泌乳期共鉴定出 218 个差异表达的 circRNAs。在 DP 阶段特异性表达的 circRNAs 数量最多，在 LL 阶段最少，表明在不同发育阶段乳腺组织中 circRNA 的表达具有时间特异性。此外，本研究还构建了与乳腺发育、免疫、物质代谢和细胞凋亡相关的 circRNA-miRNA-mRNA 竞争性内源 RNA（ceRNA）调控网络。这些发现有助于理解 circRNAs 在乳腺细胞退化和重塑中的调控作用。
