Conserved gene specifies germ cell Germ cells are the exclusive progenitors of gametes. In most studied animals, including humans, germ cells are produced only once during embryogenesis and are not replenished in adult life. DuBuc et al. studied germ cell induction in the clonal cnidarian Hydractinia symbiolongicarpus, an animal that forms germ cells continuously in adult life from stem cells that also generate somatic cells. A single transcription factor is capable of converting the animal's adult stem cells to germ cells. A similar gene also controls germ cell induction in mammalian embryos, but its action there is limited to a single event in early embryogenesis. Science, this issue p. 757 A single transcription factor commits adult stem cells to germ cell fate and induces gonad development in Hydractinia symbiolongicarpus. Clonal animals do not sequester a germ line during embryogenesis. Instead, they have adult stem cells that contribute to somatic tissues or gametes. How germ fate is induced in these animals, and whether this process is related to bilaterian embryonic germline induction, is unknown. We show that transcription factor AP2 (Tfap2), a regulator of mammalian germ lines, acts to commit adult stem cells, known as i-cells, to the germ cell fate in the clonal cnidarian Hydractinia symbiolongicarpus. Tfap2 mutants lacked germ cells and gonads. Transplanted wild-type cells rescued gonad development but not germ cell induction in Tfap2 mutants. Forced expression of Tfap2 in i-cells converted them to germ cells. Therefore, Tfap2 is a regulator of germ cell commitment across germ line–sequestering and germ line–nonsequestering animals.

中文翻译：

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转录因子 AP2 控制刺胞动物生殖细胞诱导


保守基因指定生殖细胞 生殖细胞是配子的唯一祖细胞。在大多数研究的动物（包括人类）中，生殖细胞在胚胎发生过程中仅产生一次，并且在成年后不会补充。杜布克等人。研究了克隆性刺胞动物 Hydractinia symbiolongicarpus 的生殖细胞诱导，这种动物在成年后不断地从干细胞形成生殖细胞，这些干细胞也产生体细胞。单个转录因子能够将动物的成体干细胞转化为生殖细胞。类似的基因也控制哺乳动物胚胎中生殖细胞的诱导，但其作用仅限于早期胚胎发生中的单个事件。科学，本期第 14 页。第 757 部分克隆动物在胚胎发生过程中不会隔离种系。相反，它们具有有助于体细胞组织或配子的成体干细胞。这些动物的生殖命运是如何诱导的，以及这个过程是否与两侧对称动物胚胎种系诱导有关，目前尚不清楚。我们发现转录因子 AP2 (Tfap2) 是哺乳动物生殖系的调节因子，在克隆性刺胞动物 Hydractinia symbiolongicarpus 中，其作用是将成体干细胞（称为 i 细胞）决定为生殖细胞的命运。 Tfap2突变体缺乏生殖细胞和性腺。移植的野生型细胞挽救了 Tfap2 突变体的性腺发育，但不能诱导生殖细胞。 Tfap2 在 i 细胞中的强制表达将其转化为生殖细胞。因此，Tfap2 是生殖系隔离和生殖系非隔离动物生殖细胞定型的调节剂。