Division of Molecular Genetics and Development, Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia.
Biol Reprod. 2013 Aug 15;89(2):34. doi: 10.1095/biolreprod.113.110155. Print 2013 Aug.
MicroRNAs are important regulators of developmental gene expression, but their contribution to fetal gonad development is not well understood. We have identified the evolutionarily conserved gonadal microRNAs miR-202-5p and miR-202-3p as having a potential role in regulating mouse embryonic gonad differentiation. These microRNAs are expressed in a sexually dimorphic pattern as the primordial XY gonad differentiates into a testis, with strong expression in Sertoli cells. In vivo, ectopic expression of pri-miR-202 in XX gonads did not result in molecular changes to the ovarian determination pathway. Expression of the primary transcript of miR-202-5p/3p remained low in XY gonads in a conditional Sox9-null mouse model, suggesting that pri-miR-202 transcription is downstream of SOX9, a transcription factor that is both necessary and sufficient for male sex determination. We identified the pri-miR-202 promoter that is sufficient to drive expression in XY but not XX fetal gonads ex vivo. Mutation of SOX9 and SF1 binding sites reduced ex vivo transactivation of the pri-miR-202 promoter, demonstrating that pri-miR-202 may be a direct transcriptional target of SOX9/SF1 during testis differentiation. Our findings indicate that expression of the conserved gonad microRNA, miR-202-5p/3p, is downstream of the testis-determining factor SOX9, suggesting an early role in testis development.
微小 RNA 是发育基因表达的重要调节因子，但它们在胎儿性腺发育中的作用尚不清楚。我们已经确定了保守的性腺微小 RNA miR-202-5p 和 miR-202-3p 在调节小鼠胚胎性腺分化中具有潜在作用。这些微小 RNA 以性二态模式表达，因为原始的 XY 性腺分化为睾丸，在支持细胞中强烈表达。在体内，XX 性腺中 pri-miR-202 的异位表达不会导致卵巢决定途径的分子变化。在条件性 Sox9 缺失小鼠模型中，XY 性腺中 miR-202-5p/3p 的初级转录本的表达仍然很低，这表明 pri-miR-202 的转录是 SOX9 的下游，SOX9 是雄性性别决定所必需和充分的转录因子。我们确定了 pri-miR-202 启动子，该启动子足以在体外驱动 XY 但不能在 XX 胎儿性腺中表达。SOX9 和 SF1 结合位点的突变降低了 pri-miR-202 启动子的体外转录激活，表明 pri-miR-202 可能是睾丸分化过程中 SOX9/SF1 的直接转录靶标。我们的研究结果表明，保守的性腺微小 RNA miR-202-5p/3p 的表达是睾丸决定因子 SOX9 的下游，这表明它在睾丸发育中可能具有早期作用。
