Switch from BAX-dependent to BAX-independent germ cell loss during the development of fetal mouse ovaries
Switch from BAX-dependent to BAX-independent germ cell loss during the development of fetal mouse ovaries
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DOI：
10.1242/jcs.03332
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发表时间：
2007-02-01
影响因子：
4
通讯作者：
Taketo, Teruko
中科院分区：
文献类型：
--
作者：
Alton, Michelle;Taketo, Teruko
女性生殖寿命受到卵母细胞/卵泡池的限制，这取决于进入减数分裂的生殖细胞数量和随后的卵母细胞损失。有人认为，在整个卵子发生过程中，细胞凋亡是生殖细胞消失的原因。然而，女性生殖细胞在胎儿和新生儿生命中经历不同的细胞周期时不断丢失。目前还没有令人信服的证据表明卵母细胞在体内减数分裂前期发生凋亡。在这项研究中，我们研究了缺乏BAX（一种关键的促凋亡分子）的小鼠生殖细胞群的变化。通过GCNA 1免疫标记鉴定的生殖细胞的数量，与杂合Bax（+/-）小鼠和野生型Bax（+/+）小鼠的卵巢相比，在cobacterium后14.5天（d.p.c.）并保持较高至24.5d.p.c.。然而，从14.5-24.5 d.p.c.，Bax（-/-）卵巢中的生殖细胞迅速丧失，与Bax（+/-）和Bax（+/+）卵巢中的生殖细胞平行，大多数生殖细胞进入减数分裂前期的时期。这些结果表明，虽然通过减数分裂前期的进展，卵母细胞被淘汰的BAX独立的机制。
Female reproductive life is limited by the oocyte/follicle pool, which has been determined by the number of germ cells to enter meiosis and subsequent loss of oocytes. It has been suggested that apoptosis accounts for the elimination of germ cells throughout oogenesis. However, female germ cells are lost continuously while they undergo distinct cell cycles in fetal and neonatal life. No convincing evidence has yet been provided to show apoptotic death of oocytes during meiotic prophase in vivo. In this study, we examined the change in the germ cell population in mice deficient of BAX, a key proapoptotic molecule. The number of germ cells, identified by GCNA1 immunolabeling, approximately doubled in ovaries of Bax(-/-) mice compared with ovaries of heterozygous Bax(+/-) mice and wild-type Bax(+/+) mice by 14.5 days post coitum (d.p.c.) and remained higher up to 24.5 d.p.c. However, there was a rapid loss of germ cells in Bax(-/-) ovaries, paralleling that in Bax(+/-) and Bax(+/+) ovaries from 14.5-24.5 d.p.c., a period in which most germ cells entered and progressed in meiotic prophase. These results suggest that, while progressing through meiotic prophase, oocytes are eliminated by a BAX-independent mechanism.