Laboratory of Developmental Biology, Department of Morphology and Genetics, Federal University of Sao Paulo, Sao Paulo, Brazil.
Cells Tissues Organs. 2012;195(5):443-55. doi: 10.1159/000329245. Epub 2011 Sep 5.
Germ cells are the only cells capable of transmitting genetic information from generation to generation. Germ cell development has been widely studied in different species. Among mammals, the mouse is the model used in the majority of studies on germ cell differentiation, sex determination and genetics. In the present study, we suggest that the rat is also a very important model for the investigation of the mechanisms of germ cell development. To study rat germ cell development and compare it with that of mouse, the germ cell markers germ cell nuclear antigen 1 (GCNA1), OCT4, mouse vasa homologue (MVH) and specific surface embryonic antigen 1 (SSEA1) were immunolabeled at different phases of embryonic and postnatal development. SSEA1 and GCNA1 were not detected in rat primordial germ cells and fetal gonocytes. GCNA1 was detected postnatally and was present only in leptotene, zygotene and early pachytene spermatocytes. On the other hand, in mice, these markers were detected in germ cells as soon as 11.5 days postcoitum (dpc). MVH was detected in migrating rat primordial germ cells as well as in those that have already colonized the gonads, whereas in mice, MVH is detected only in germ cells that have reached the gonads. In rats, OCT4-positive germ cells were detected from 13 to 17 dpc, but not at 19 dpc or in postnatal testes. This is in contrast with mice that show OCT4 labeling in both embryonic and adult testes. These data suggest that primordial germ cell development in rats and mice shows considerable differences and that the rat may also be an important model to study the embryonic development of germ cells.
生殖细胞是唯一能够将遗传信息代代相传的细胞。生殖细胞的发育已在不同物种中得到广泛研究。在哺乳动物中，老鼠是用于研究生殖细胞分化、性别决定和遗传学的大多数研究的模型。在本研究中，我们认为大鼠也是研究生殖细胞发育机制的重要模型。为了研究大鼠生殖细胞的发育并将其与小鼠进行比较，我们在胚胎和出生后发育的不同阶段对生殖细胞标志物生殖细胞核抗原 1 (GCNA1)、OCT4、小鼠同源物 (MVH) 和特异性表面胚胎抗原 1 (SSEA1) 进行了免疫标记。SSEA1 和 GCNA1 在大鼠原始生殖细胞和胎儿性原细胞中未被检测到。GCNA1 在出生后被检测到，仅存在于细线期、合线期和早期粗线期精母细胞中。另一方面，在小鼠中，这些标志物在受精后 11.5 天 (dpc) 即可在生殖细胞中检测到。MVH 在迁移的大鼠原始生殖细胞以及已经定植于性腺的原始生殖细胞中均被检测到，而在小鼠中，MVH 仅在到达性腺的生殖细胞中被检测到。在大鼠中，从 13 到 17 dpc 检测到 OCT4 阳性生殖细胞，但在 19 dpc 或出生后睾丸中未检测到。这与在胚胎和成年睾丸中均显示 OCT4 标记的小鼠形成对比。这些数据表明，大鼠和小鼠的原始生殖细胞发育存在明显差异，大鼠也可能是研究生殖细胞胚胎发育的重要模型。
