Zebrafish dazl regulates cystogenesis and germline stem cell specification during the primordial germ cell to germline stem cell transition
Zebrafish dazl regulates cystogenesis and germline stem cell specification during the primordial germ cell to germline stem cell transition
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DOI：
10.1242/dev.187773
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发表时间：
2021-04-01
期刊：
影响因子：
4.6
通讯作者：
Marlow, Florence L.
中科院分区：
文献类型：
--
作者：
Bertho, Sylvain;Clapp, Mara;Marlow, Florence L.
生殖力和配子储备通过生殖系干细胞的不对称分裂来维持，以产生新的干细胞或分化为配子的子代。在进入减数分裂之前，有性动物的分化生殖细胞（GC）通常经历囊形成。这个进化上保守的过程涉及GC子细胞（成囊细胞）的同步且不完全的有丝分裂，以产生通过细胞间桥连接的姐妹细胞，这些细胞促进物质交换，以支持配子祖细胞群体的快速扩张。在这里，我们研究了斑马鱼的囊形成，发现早期GC由环形通道连接，并表明无精子症样蛋白（Dazl），一种保守的脊椎动物RNA结合蛋白（Rbp），是这一过程的调节剂。对dazl突变体的分析揭示了Dazl在减数分裂转变前调节不完全胞质分裂、生殖系囊肿形成和生殖系干细胞特化中的重要作用。因此，dazl突变GC形成有缺陷的环管，并最终保持为不能分化为性母细胞的单个细胞。除了促进成囊细胞分裂和减数分裂进入，dazl是生殖系干细胞建立和生育所必需的。
Fertility and gamete reserves are maintained by asymmetric divisions of the germline stem cells to produce new stem cells or daughters that differentiate as gametes. Before entering meiosis, differentiating germ cells (GCs) of sexual animals typically undergo cystogenesis. This evolutionarily conserved process involves synchronous and incomplete mitotic divisions of a GC daughter (cystoblast) to generate sister cells connected by intercellular bridges that facilitate the exchange of materials to support rapid expansion of the gamete progenitor population. Here, we investigated cystogenesis in zebrafish and found that early GCs are connected by ring canals, and show that Deleted in azoospermia-like (Dazl), a conserved vertebrate RNA-binding protein (Rbp), is a regulator of this process. Analysis of dazl mutants revealed the essential role of Dazl in regulating incomplete cytokinesis, germline cyst formation and germline stem cell specification before the meiotic transition. Accordingly, dazl mutant GCs form defective ring canals, and ultimately remain as individual cells that fail to differentiate as meiocytes. In addition to promoting cystoblast divisions and meiotic entry, dazl is required for germline stem cell establishment and fertility.