Lin Zachary Yu-Ching, Hirano Takamasa, Shibata Shinsuke, Seki Naomi M, Kitajima Ryunosuke, Sedohara Ayako, Siomi Mikiko C, Sasaki Erika, Siomi Haruhiko, Imamura Masanori, Okano Hideyuki
Department of Physiology, School of Medicine, Keio University, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan.
Department of Molecular Biology, School of Medicine, Keio University, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan.
Dev Biol. 2015 Apr 1;400(1):43-58. doi: 10.1016/j.ydbio.2015.01.014. Epub 2015 Jan 23.
Mammalian spermatogenesis has been investigated extensively in rodents and a strictly controlled developmental process has been defined at cellular and molecular levels. In comparison, primate spermatogenesis has been far less well characterized. However, important differences between primate and rodent spermatogenesis are emerging so it is not always accurate to extrapolate findings in rodents to primate systems. Here, we performed an extensive immunofluorescence study of spermatogenesis in neonatal, juvenile, and adult testes in the common marmoset (Callithrix jacchus) to determine primate-specific patterns of gene expression that underpin primate germ cell development. Initially we characterized adult spermatogonia into two main classes; mitotically active C-KIT(+)Ki67(+) cells and mitotically quiescent SALL4(+)PLZF(+)LIN28(+)DPPA4(+) cells. We then explored the expression of a set of markers, including PIWIL1/MARWI, VASA, DAZL, CLGN, RanBPM, SYCP1 and HAPRIN, during germ cell differentiation from early spermatocytes through round and elongating spermatids, and a clear program of gene expression changes was determined as development proceeded. We then examined the juvenile marmoset testis. Markers of gonocytes demonstrated two populations; one that migrates to the basal membrane where they form the SALL4(+) or C-KIT(+) spermatogonia, and another that remains in the lumen of the seminiferous tubule. This later population, historically identified as pre-spermatogonia, expressed meiotic and apoptotic markers and were eliminated because they appear to have failed to correctly migrate. Our findings provide the first platform of gene expression dynamics in adult and developing germ cells of the common marmoset. Although we have characterized a limited number of genes, these results will facilitate primate spermatogenesis research and understanding of human reproduction.
哺乳动物精子发生在啮齿动物中已得到广泛研究，并且在细胞和分子水平上已确定了一个严格控制的发育过程。相比之下，灵长类动物的精子发生特征尚不明确。然而，灵长类动物和啮齿动物精子发生之间的重要差异正在显现，因此将啮齿动物的研究结果外推到灵长类动物系统并不总是准确的。在这里，我们对普通狨猴（Callithrix jacchus）的新生儿、幼年和成年睾丸中的精子发生进行了广泛的免疫荧光研究，以确定支持灵长类生殖细胞发育的灵长类特异性基因表达模式。最初，我们将成年精原细胞分为两大类；有丝分裂活跃的C-KIT(+)Ki67(+)细胞和有丝分裂静止的SALL4(+)PLZF(+)LIN28(+)DPPA4(+)细胞。然后，我们研究了一组标记物的表达，包括PIWIL1/MARWI、VASA、DAZL、CLGN、RanBPM、SYCP1和HAPRIN，在从早期精母细胞到圆形和伸长精子细胞的生殖细胞分化过程中，随着发育的进行，确定了一个明确的基因表达变化程序。然后，我们检查了幼年狨猴的睾丸。生殖母细胞的标记物显示出两个群体；一个迁移到基底膜，在那里它们形成SALL4(+)或C-KIT(+)精原细胞，另一个留在生精小管的管腔中。这后一个群体，历史上被鉴定为前精原细胞，表达减数分裂和凋亡标记物，并被消除，因为它们似乎未能正确迁移。我们的研究结果提供了普通狨猴成年和发育中生殖细胞基因表达动态的第一个平台。虽然我们只研究了有限数量的基因，但这些结果将有助于灵长类精子发生的研究和对人类生殖的理解。
