A role for Lin28 in primordial germ-cell development and germ-cell malignancy.
A role for Lin28 in primordial germ-cell development and germ-cell malignancy.
复制标题
作者：
小鼠胚胎中最早的原始生殖细胞(PGCs)的稀有和不可及，阻碍了研究生殖细胞指定的分子机制的努力。Stella标志着细菌谱系中的微小创建者群体。在这里，我们在体外将携带Stella转基因报告的小鼠胚胎干细胞(ESCs)分化为假定的PGCs。Stella+细胞具有类似于胚胎来源的PGCs的转录特征，并且像体内的同类细胞一样，以一种时间依赖的方式丢失印记。利用抑制性RNA在体外筛选对Stella+细胞发育影响的候选基因，我们发现LIN28是let-7 microRNA加工的负调控因子，对于PGC的正常发育是必不可少的。我们进一步证明，LET-7靶标和PGC规范的主调控子Blimp1可以挽救PGC发育过程中Lin28缺陷的影响，从而建立了Lin28在PGC规范过程中的作用机制。Lin28的过表达促进了体外Stella+细胞和嵌合胚胎中PGCs的形成，并与人类生殖细胞肿瘤有关。体外从胚胎干细胞分化为PGCs的过程概括了体内配子发育的早期阶段，并为发现与生殖细胞发育和恶性相关的新基因提供了一个可访问的系统。
The rarity and inaccessibility of the earliest primordial germ cells (PGCs) in the mouse embryo thwarts efforts to investigate molecular mechanisms of germ cell specification. Stella marks the minute founder population of the germ lineage. Here we differentiate mouse embryonic stem cells (ESCs) carrying a Stella transgenic reporter into putative PGCs in vitro. The Stella+ cells possess a transcriptional profile similar to embryo-derived PGCs, and like their counterparts in vivo, lose imprints in a time-dependent manner. Using inhibitory RNAs to screen candidate genes for effects on the development of Stella+ cells in vitro, we discovered that Lin28, a negative regulator of let-7 microRNA processing, is essential for proper PGC development. We further show that Blimp1, a let-7 target and a master regulator of PGC specification, can rescue the effect of Lin28-deficiency during PGC development, thereby establishing a mechanism of action for Lin28 during PGC specification. Over-expression of Lin28 promotes formation of Stella+ cells in vitro and PGCs in chimeric embryos, and is associated with human germ cell tumours. The differentiation of putative PGCs from ESCs in vitro recapitulates the early stages of gamete development in vivo, and provides an accessible system for discovering novel genes involved in germ cell development and malignancy.