Bachvarova Rosemary F, Masi Thomas, Drum Matthew, Parker Nathan, Mason Ken, Patient Roger, Johnson Andrew D
Department of Cell Biology and Development, Weill Medical College of Cornell University, New York, New York, USA.
Dev Dyn. 2004 Dec;231(4):871-80. doi: 10.1002/dvdy.20195.
Primordial germ cells (PGCs) in embryos of mammals and urodele amphibians are formed by induction in the absence of germ plasm. We describe expression of four germ cell-related genes through the germ cell cycle of the axolotl. The orthologs of vasa and daz-like are up-regulated in PGCs of tail bud embryos before the gonad forms and are expressed throughout the female germ cell cycle. Mammalian Oct-4 is a marker of pluripotency in embryonic cells. Axolotl Oct-4 has higher homology to Oct-4 than that found in other vertebrates. It is expressed in the equivalent of the mouse epiblast, in the posterior mesoderm of late gastrulae that gives rise to PGCs, and in diplotene growing oocytes, but not in presumptive PGCs after gastrulation. Finally, a c-kit homolog is expressed in gonadal oogonia and growing oocytes as in mice but is also not found in PGCs. The expression pattern in urodele gonadal germ cells is similar to that of other vertebrates, although the pattern in pregonadal PGCs is distinctly different from that of mice. We conclude that PGCs are restricted to the germ line later in urodeles than in mice or lack migration and proliferation programs.
哺乳动物和有尾两栖动物胚胎中的原始生殖细胞（PGCs）是在没有生殖质的情况下通过诱导形成的。我们描述了四种生殖细胞相关基因在蝾螈生殖细胞周期中的表达情况。vasa和daz-like的直系同源基因在性腺形成之前的尾芽胚胎的PGCs中上调，并在雌性生殖细胞周期中全程表达。哺乳动物的Oct-4是胚胎细胞多能性的标志物。蝾螈的Oct-4与Oct-4的同源性高于其他脊椎动物。它在相当于小鼠上胚层的结构中表达，在晚期原肠胚中产生PGCs的后中胚层中表达，在双线期生长的卵母细胞中表达，但在原肠胚形成后的假定PGCs中不表达。最后，一种c-kit同源物在性腺卵原细胞和生长中的卵母细胞中表达，与小鼠中的情况相同，但在PGCs中也未发现。有尾两栖动物性腺生殖细胞中的表达模式与其他脊椎动物相似，尽管性腺前PGCs中的模式与小鼠明显不同。我们得出结论，有尾两栖动物中PGCs在生殖系中的限制比小鼠晚，或者缺乏迁移和增殖程序。
