Li Taotao, Luo Ruirui, Wang Xia, Wang Huihui, Zhao Xingxu, Guo Yunxia, Jiang Haitao, Ma Youji
College of Animal Science and Technology, Gansu Agricultural University, Lanzhou, China.
College of Veterinary Medicine, Gansu Agricultural University, Lanzhou, China.
Front Cell Dev Biol. 2021 Mar 19;9:627439. doi: 10.3389/fcell.2021.627439. eCollection 2021.
Circular RNAs (circRNAs) have been shown to function in the reproductive systems including testis. However, their expression, as well as function in testicular development of sheep remain undefined. Herein, we performed RNA sequencing to reveal circRNA temporal expression patterns in testes of Tibetan sheep from different stages of maturation (3M, 3-month-old; 1Y, 1-year-old; 3Y, 3-year-old). A total of 3,982, 414, and 4,060 differentially expressed (DE) circRNAs were uncovered from 3M vs 1Y, 1Y vs 3Y, and 3M vs 3Y, respectively. Functional enrichment assessment indicated that the source genes of DE circRNAs were primarily engaged in spermatogenesis and testicular immune privilege including blood-testis barrier (BTB). We subsequently constructed the core circRNA-miRNA-mRNA interaction network for genes related to testicular function, such as spermatogenesis, germ cell development, BTB, and cell cycle/meiosis. Furthermore, we validated the target associations between either circ_024949, circ_026259 or IGF1, and oar-miR-29b in this network, and revealed their similar expression signatures in developmental testes that they were extensively expressed in germ cells, Leydig cells, and Sertoli cells, thus suggesting their broad functions in the functional maintenance of Leydig cells and Sertoli cells, as well as the development and maturation of male germ cells. Meanwhile, circ_026259 was shown to promote IGF1 expression through inhibition of oar-miR-29b in sheep Sertoli cells. This work gives the first global view for the expression and regulation of circRNAs in sheep testis, which will be helpful for providing new insights into the molecular mechanism of ovine testis function.
环状RNA（circRNAs）已被证明在包括睾丸在内的生殖系统中发挥作用。然而，它们在绵羊睾丸发育中的表达及其功能仍不明确。在此，我们进行了RNA测序，以揭示不同成熟阶段（3个月龄、1岁、3岁）的藏绵羊睾丸中circRNA的时间表达模式。分别从3个月龄与1岁、1岁与3岁、3个月龄与3岁的比较中发现了3982、414和4060个差异表达的circRNA。功能富集评估表明，差异表达circRNA的来源基因主要参与精子发生和睾丸免疫豁免，包括血睾屏障（BTB）。随后，我们构建了与睾丸功能相关基因（如精子发生、生殖细胞发育、BTB和细胞周期/减数分裂）的核心circRNA-miRNA-mRNA相互作用网络。此外，我们在该网络中验证了circ_024949、circ_026259或IGF1与oar-miR-29b之间的靶向关联，并揭示了它们在发育中的睾丸中相似的表达特征，即在生殖细胞、睾丸间质细胞和支持细胞中广泛表达，从而表明它们在睾丸间质细胞和支持细胞的功能维持以及雄性生殖细胞的发育和成熟中具有广泛的功能。同时，circ_026259在绵羊支持细胞中通过抑制oar-miR-29b促进IGF1表达。这项工作首次全面展示了circRNAs在绵羊睾丸中的表达和调控，有助于为绵羊睾丸功能的分子机制提供新的见解。
