Xavier F, Lagarrigue S, Guillomot M, Gaillard-Sanchez I
URA 1291 CNRS, Institut National de la Recherche Agronomique, Station de Physiologie Animale, Jouy-en-Josas, France.
Mol Reprod Dev. 1997 Feb;46(2):127-37. doi: 10.1002/(SICI)1098-2795(199702)46:2<127::AID-MRD3>3.0.CO;2-S.
Expression of c-fos and jun protooncogenes was analyzed in the ovine extraembryonic trophoblast from days 14-18 of gestation, using Northern and Western blotting and immunohistochemistry. This study was carried out in relation to the early implantation process and the expression of interferon-tau, which is secreted in large amounts for a few days before implantation. Our results demonstrated that c-fos, c-jun, and junB were differently expressed in the ovine trophoblast around the time of implantation. The c-fos mRNA and protein were detected at high levels prior to attachment and decreased thereafter, following the pattern of expression of interferon-tau, whereas c-jun expression was maintained at relatively high levels during the implantation process. By contrast, the levels of junB mRNA and protein decreased prior to attachment. Immunohistochemical studies indicated that JunB, like C-Fos and interferon-tau, was no longer expressed in the trophoblastic cells which had established cellular contacts with the uterine epithelium. A striking finding in this study is the temporal correlation between the accumulation of c-Fos and c-Jun proteins and the expression of the interferon-tau (days 14 and 15 of gestation). We also showed by gel-retardation assays that an AP-1-like site present in the promoter of one interferon-tau gene was functional in vitro, as judged by its ability to bind day-15 trophoblast nuclear protein extracts. Nuclear proteins binding to this site had the characteristics of AP-1, as judged by the ability to be competed efficiently by a consensus TRE (12.0-tetradecanoyl phorbol 13-acetate-responsive element)-site oligonucleotide and by antibodies to c-Fos and Jun proteins. These results suggest that Fos and Jun could form regulatory complexes of interferon-tau expression and/or are regulated by common mechanisms which are still unknown.
利用Northern印迹法、Western印迹法和免疫组织化学方法，分析了妊娠第14 - 18天绵羊胚胎外滋养层中c-fos和jun原癌基因的表达。本研究围绕早期着床过程以及着床前几天大量分泌的干扰素-tau的表达展开。我们的结果表明，c-fos、c-jun和junB在绵羊着床前后的滋养层中表达各异。在附着前可检测到高水平的c-fos mRNA和蛋白，此后随着干扰素-tau的表达模式而下降，而c-jun的表达在着床过程中维持在相对较高水平。相比之下，junB mRNA和蛋白水平在附着前下降。免疫组织化学研究表明，与C-Fos和干扰素-tau一样，JunB在已与子宫上皮建立细胞接触的滋养层细胞中不再表达。本研究中的一个显著发现是c-Fos和c-Jun蛋白的积累与干扰素-tau的表达（妊娠第14天和15天）之间存在时间相关性。我们还通过凝胶阻滞试验表明，一个干扰素-tau基因启动子中存在的类AP-1位点在体外具有功能，这是根据其与第15天滋养层核蛋白提取物结合的能力判断的。结合该位点的核蛋白具有AP-1的特征，这是根据其被共有TRE（12-O-十四烷酰佛波醇-13-乙酸酯反应元件）位点寡核苷酸以及抗c-Fos和Jun蛋白抗体有效竞争的能力判断的。这些结果表明，Fos和Jun可能形成干扰素-tau表达的调节复合物和/或受仍未知的共同机制调控。
