Thompson Winston E, Asselin Eric, Branch Alicia, Stiles Jonathan K, Sutovsky Peter, Lai Liangxue, Im Gi-Sun, Prather Randall S, Isom S Clay, Rucker Edmund, Tsang Benjamin K
Department of Obstetrics and Gynecology and Cooperative Reproductive Science Research Center, Morehouse School of Medicine, Atlanta, GA 30310, USA.
Biol Reprod. 2004 Jul;71(1):282-90. doi: 10.1095/biolreprod.103.024125. Epub 2004 Mar 17.
Prohibitin is a ubiquitous and highly conserved protein implicated as an important regulator in cell survival. Prohibitin content is inversely associated with cell proliferation, but it increases during granulosa cell differentiation as well as in earlier events of apoptosis in a temperature-sensitive granulosa cell line. In the present study, we have characterized the spatial expression patterns for prohibitin using established in vivo models for the induction of follicular development and atresia in the mammalian ovary. Comparative Western blot analyses of granulosa cell lysates from control ovaries and from ovaries primed with eCG or treated with eCG plus anti-eCG (gonadotropin withdrawal) were conducted. Prohibitin was immunolocalized in rat ovarian sections probed with antibodies against either proliferating cell nuclear antigen (PCNA) or cholesterol side-chain cleavage cytochrome P450 (P450(scc)) or in terminal deoxynucleotidyl transferase-mediated dUTP nick end labeled sections. Additionally, porcine oocytes, zygotes, and blastocyts were also immunolocalized with prohibitin antibody. Immunolocalization revealed the presence of prohibitin in granulosa cells, theca-interstitial cells, and the oocyte. The results indicate that prohibitin protein expression in the gonadotropin-treated cells was upregulated. Immunoreactivity of prohibitin was inversely related to PCNA expression during follicular maturation and colocalized with P450(scc). Prohibitin appeared to be translocated from the cytoplasm to the nucleus in atretic follicles, germinal vesicle-stage oocytes, zygotes, and blastocysts. These results suggest that prohibitin has several functional regulatory roles in granulosa and theca-interstitial cells and in the ovum during follicular maturation and atresia. It is likely that prohibitin may play an important role in determining the fate of these cells and eventual follicular destiny.
抑制素是一种普遍存在且高度保守的蛋白质，被认为是细胞存活的重要调节因子。抑制素含量与细胞增殖呈负相关，但在颗粒细胞分化过程中以及在对温度敏感的颗粒细胞系凋亡的早期事件中会增加。在本研究中，我们利用已建立的体内模型来诱导哺乳动物卵巢卵泡发育和闭锁，从而确定了抑制素的空间表达模式。对来自对照卵巢以及用促性腺激素释放激素（eCG）预处理或用eCG加抗eCG（促性腺激素撤药）处理的卵巢的颗粒细胞裂解物进行了比较蛋白质免疫印迹分析。用抗增殖细胞核抗原（PCNA）或胆固醇侧链裂解细胞色素P450（P450(scc)）抗体探测大鼠卵巢切片，或在末端脱氧核苷酸转移酶介导的dUTP缺口末端标记切片中对抑制素进行免疫定位。此外，还使用抑制素抗体对猪卵母细胞、受精卵和囊胚进行了免疫定位。免疫定位显示颗粒细胞、卵泡膜间质细胞和卵母细胞中存在抑制素。结果表明，促性腺激素处理细胞中抑制素蛋白表达上调。在卵泡成熟过程中，抑制素的免疫反应性与PCNA表达呈负相关，并与P450(scc)共定位。在闭锁卵泡、生发泡期卵母细胞、受精卵和囊胚中，抑制素似乎从细胞质转移到细胞核。这些结果表明，抑制素在卵泡成熟和闭锁过程中，在颗粒细胞和卵泡膜间质细胞以及卵子中具有多种功能调节作用。抑制素很可能在决定这些细胞的命运和最终卵泡命运方面发挥重要作用。
