Otsuka Saori, Konno Akihiro, Hashimoto Yoshiharu, Sasaki Nobuya, Endoh Daiji, Kon Yasuhiro
Laboratory of Anatomy, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo 060-0818, Japan.
Biol Reprod. 2008 Jul;79(1):9-16. doi: 10.1095/biolreprod.107.064519. Epub 2008 Mar 19.
Although mammals produce either sperm or eggs depending on their sex, we found oocytes in the testes of newborn MRL/MpJ male mice. In the present study, we report the morphological characteristics of testicular oocytes, the postnatal change of oocyte number per testis, and the expression of a few oocyte-specific genes in the testes of MRL/MpJ mice. The testicular oocytes had a diameter of 50-70 microm and were surrounded by zonae pellucidae, which were observed between oocytes and follicular epithelial cells. Ultrastructurally, the testicular oocytes contained numerous microvilli and cortical granules, receiving cytoplasmic projections from follicular epithelial cells. The testicular oocytes appeared as early as at birth, and the largest number was found on Day 14. The testicular oocytes were detected in only MRL strains and B6MRLF1, but not in C57BL/6, C3H/He, BALB/c, DBA/2, A/J, and MRLB6F1. The expression of the oocyte-specific genes Zp1, Zp2, Zp3, and Omt2a was detected in testes from MRL/MpJ mice. These results suggest that newborn male MRL/MpJ mice with XY chromosomes can produce oocytes in their testes and that one of the genes causing this exists on the Y chromosome.
尽管哺乳动物根据性别产生精子或卵子，但我们在新生MRL/MpJ雄性小鼠的睾丸中发现了卵母细胞。在本研究中，我们报告了睾丸卵母细胞的形态特征、每个睾丸中卵母细胞数量的出生后变化，以及MRL/MpJ小鼠睾丸中一些卵母细胞特异性基因的表达。睾丸卵母细胞直径为50 - 70微米，被透明带包围，在卵母细胞和卵泡上皮细胞之间可见。超微结构上，睾丸卵母细胞含有大量微绒毛和皮质颗粒，接受来自卵泡上皮细胞的细胞质突起。睾丸卵母细胞最早在出生时出现，在第14天数量最多。仅在MRL品系和B6MRLF1中检测到睾丸卵母细胞，而在C57BL/6、C3H/He、BALB/c、DBA/2、A/J和MRLB6F1中未检测到。在MRL/MpJ小鼠的睾丸中检测到了卵母细胞特异性基因Zp1、Zp2、Zp3和Omt2a的表达。这些结果表明，具有XY染色体的新生雄性MRL/MpJ小鼠能够在其睾丸中产生卵母细胞，并且导致这种现象的基因之一存在于Y染色体上。
