Ness J M, Kasson B G
Department of Pharmacology, College of Medicine, University of Iowa, Iowa City 52242.
Mol Cell Endocrinol. 1992 Dec;90(1):17-25. doi: 10.1016/0303-7207(92)90096-o.
c-Fos and c-jun are immediate early proto-oncogenes encoding proteins for the heterodimer AP-1, a DNA binding complex which regulates gene transcription. In order to investigate the presence and potential gonadotropin regulation of mRNAs for these proto-oncogenes in rat granulosa cells, we used Northern blotting of total RNA from cultured cells. Granulosa cells obtained from diethylstilbestrol (DES)-treated weanling rats were challenged with follicle-stimulating hormone (FSH), luteinizing hormone (LH), human chorionic gonadotropin (hCG), dibutyryl cAMP ((Bu)2cAMP) or tetradecanoyl-13-phorbol acetate (TPA) either 2.5 h after cell isolation (day 0) or following a 2-day pretreatment with FSH (day 2). Freshly isolated cells treated with FSH exhibited 4-fold and 3-fold increases in c-fos and c-jun mRNAs, respectively, within 30 min. Two hours after FSH treatment, both c-fos and c-jun message levels diminished to near control levels. Granulosa cells pretreated for 2 days with FSH, then re-challenged with FSH, showed similar increases in both c-fos and c-jun messages. These effects were dose- and time-dependent on both day 0 and day 2. Likewise, (Bu)2cAMP also increased c-fos and c-jun mRNAs in a time- and dose-dependent manner on both day 0 and day 2. In contrast, LH or hCG minimally increased c-fos and c-jun mRNAs on day 0, but on day 2, both hormones markedly increased message levels in a manner similar to that seen with FSH. Analogous effects were observed with TPA which minimally stimulated c-fos and c-jun mRNAs on day 0, but markedly increased these messages on day 2. These studies demonstrate that c-fos and c-jun mRNAs can be induced in cultured rat granulosa cells by acute gonadotropin, (Bu)2cAMP or phorbol ester treatment and suggest that these immediate early proto-oncogenes may play a role in granulosa cell function.
c-Fos和c-jun是即刻早期原癌基因，它们编码异二聚体AP-1的蛋白质，AP-1是一种调节基因转录的DNA结合复合物。为了研究大鼠颗粒细胞中这些原癌基因mRNA的存在情况及其潜在的促性腺激素调节作用，我们对培养细胞的总RNA进行了Northern印迹分析。从己烯雌酚（DES）处理的断奶大鼠获得的颗粒细胞，在细胞分离后2.5小时（第0天）或用促卵泡激素（FSH）预处理2天（第2天）后，用促卵泡激素（FSH）、促黄体生成素（LH）、人绒毛膜促性腺激素（hCG）、二丁酰环磷酸腺苷（(Bu)2cAMP）或十四酰佛波醇乙酸酯（TPA）进行刺激。新鲜分离的细胞用FSH处理后，在30分钟内c-fos和c-jun mRNA分别增加了4倍和3倍。FSH处理2小时后，c-fos和c-jun的mRNA水平均降至接近对照水平。用FSH预处理2天的颗粒细胞，再用FSH刺激，c-fos和c-jun的mRNA也有类似的增加。这些效应在第0天和第2天都呈剂量和时间依赖性。同样，(Bu)2cAMP在第0天和第2天也以时间和剂量依赖性方式增加c-fos和c-jun mRNA。相比之下，LH或hCG在第0天对c-fos和c-jun mRNA的增加作用最小，但在第2天，这两种激素均以类似于FSH的方式显著增加mRNA水平。TPA也观察到类似的效应，它在第0天对c-fos和c-jun mRNA的刺激作用最小，但在第2天显著增加这些mRNA。这些研究表明，急性促性腺激素、(Bu)2cAMP或佛波酯处理可诱导培养的大鼠颗粒细胞中的c-fos和c-jun mRNA，提示这些即刻早期原癌基因可能在颗粒细胞功能中发挥作用。
