Hartley P S, Bayne R A L, Robinson L L L, Fulton N, Anderson R A
Medical Research Council Human Reproductive Sciences Unit, Centre for Reproductive Biology, 37 Chalmers Street, Edinburgh, Scotland, UK EH3 9ET.
J Clin Endocrinol Metab. 2002 Jul;87(7):3417-27. doi: 10.1210/jcem.87.7.8644.
The regulation of germ cell number in the developing ovary is central to female reproduction. Members of the Bcl-2 family of proapoptotic and antiapoptotic proteins have been implicated in this process in rodents. We investigated the expression of Mcl-1, Bcl-2, Bax, and BAD at 13-21 gestational wk in the human fetal ovary and of Mcl-1 in the adult ovary. mRNA expression of Mcl-1 and its short form Mcl-1s, Bcl-2, Bax, and BAD was demonstrated in fetal ovary by RT-PCR. Hybridization array analysis suggested a selective increase in Mcl-1 expression between 14 and 18 wk gestation, which was confirmed by quantitative PCR. There was a corresponding change in the expression of Mcl-1 protein, detected by immunohistochemistry, from germ cells at the periphery of the ovary at 14-16 wk to the largest germ cells, including oocytes within newly formed primordial follicles, at 21 wk. Mcl-1 was also expressed by oocytes of primordial and preantral follicles in the adult. Bax and BAD immunostaining was detected in both somatic and germ cells in the fetal ovary, whereas Bcl-2 was restricted to somatic cells: no changes in expression were observed. Apoptotic cells, detected by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling, were observed in all fetal ovaries but were infrequent. These results confirm that Bcl-2 family members are differentially expressed in several cell types within the developing human ovary. Increased mRNA expression and the changing distribution of Mcl-1 in germ cells as they develop into primordial follicles as well as persistence in the growing oocyte in the adult may indicate an important role for this survival/antiapoptotic factor throughout germ cell development and maturation.
发育中卵巢的生殖细胞数量调控是雌性生殖的核心。促凋亡和抗凋亡蛋白的Bcl-2家族成员在啮齿动物的这一过程中发挥了作用。我们研究了人胎儿卵巢妊娠13 - 21周时Mcl-1、Bcl-2、Bax和BAD的表达以及成年卵巢中Mcl-1的表达。通过RT-PCR在胎儿卵巢中证实了Mcl-1及其短形式Mcl-1s、Bcl-2、Bax和BAD的mRNA表达。杂交阵列分析表明，妊娠14至18周期间Mcl-1表达选择性增加，这通过定量PCR得到证实。通过免疫组织化学检测，Mcl-1蛋白的表达发生了相应变化，从14 - 16周时卵巢周边的生殖细胞到21周时包括新形成原始卵泡内的卵母细胞在内的最大生殖细胞。成年卵巢中原始卵泡和窦前卵泡的卵母细胞也表达Mcl-1。在胎儿卵巢的体细胞和生殖细胞中均检测到Bax和BAD免疫染色，而Bcl-2仅限于体细胞：未观察到表达变化。通过末端脱氧核苷酸转移酶介导的dUTP缺口末端标记检测到的凋亡细胞在所有胎儿卵巢中均有观察到，但数量很少。这些结果证实，Bcl-2家族成员在发育中的人卵巢的几种细胞类型中差异表达。随着生殖细胞发育成原始卵泡，Mcl-1的mRNA表达增加且分布发生变化，以及在成年生长中的卵母细胞中持续存在，这可能表明这种存活/抗凋亡因子在整个生殖细胞发育和成熟过程中发挥重要作用。
