Estermann Martin A, Major Andrew T, Smith Craig A
Department of Anatomy and Developmental Biology, Monash Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia.
Front Cell Dev Biol. 2020 Dec 18;8:616387. doi: 10.3389/fcell.2020.616387. eCollection 2020.
The gonads of vertebrate embryos are unique among organs because they have a developmental choice; ovary or testis formation. Given the importance of proper gonad formation for sexual development and reproduction, considerable research has been conducted over the years to elucidate the genetic and cellular mechanisms of gonad formation and sexual differentiation. While the molecular trigger for gonadal sex differentiation into ovary of testis can vary among vertebrates, from egg temperature to sex-chromosome linked master genes, the downstream molecular pathways are largely conserved. The cell biology of gonadal formation and differentiation has long thought to also be conserved. However, recent discoveries point to divergent mechanisms of gonad formation, at least among birds and mammals. In this mini-review, we provide an overview of cell lineage allocation during gonadal sex differentiation in the mouse model, focusing on the key supporting and steroidogenic cells and drawing on recent insights provided by single cell RNA-sequencing. We compare this data with emerging information in the chicken model. We highlight surprising differences in cell lineage specification between species and identify gaps in our current understanding of the cell biology underlying gonadogenesis.
脊椎动物胚胎的性腺在器官中独一无二，因为它们在发育过程中有一个选择：形成卵巢或睾丸。鉴于正常性腺形成对性发育和繁殖的重要性，多年来人们进行了大量研究，以阐明性腺形成和性别分化的遗传和细胞机制。虽然脊椎动物中性腺向卵巢或睾丸分化的分子触发因素各不相同，从卵的温度到与性染色体相关的主控基因，但下游分子途径在很大程度上是保守的。长期以来，人们一直认为性腺形成和分化的细胞生物学也是保守的。然而，最近的发现表明，至少在鸟类和哺乳动物中，性腺形成的机制存在差异。在这篇小型综述中，我们概述了小鼠模型中性腺性别分化过程中的细胞谱系分配，重点关注关键的支持细胞和类固醇生成细胞，并借鉴单细胞RNA测序提供的最新见解。我们将这些数据与鸡模型中的新信息进行比较。我们强调了不同物种之间在细胞谱系特化方面令人惊讶的差异，并指出了我们目前对性腺发生背后细胞生物学理解上的空白。
