Function of placenta-specific transcription factor GCMa in the development of the placenta

GCMa/1是仅在胎盘中表达的转录因子。它是合胞母细胞发育所必需的。该因子的零突变导致胚胎早期死亡，我们首先计划制备针对该蛋白的特异性抗体。从大肠杆菌中表达并纯化了hGCMa蛋白，制备了hGCMa的多克隆抗体。杆菌1)抗体检测大肠杆菌表达的hGCMa/1。杆菌和昆虫细胞。在正常足月胎盘中检测到真实的hGCMa/1，在小鼠胎盘中也检测到mGCMa/1。该抗体在胎盘的绒毛膜绒毛中检测到hGCMa 1，其中已检测到芳香化酶和hCG a。该结果进一步证实了我们先前的发现，即hGCMa/1对于这些基因的表达是必需的（Yamada等，J.Biol.Chem. 1999 274 32279-32286）。我们还试图获得针对该蛋白质的小鼠单克隆抗体。2)在E.大肠杆菌，昆虫细胞，正常足月胎盘中的真实hGCMa/1，以及小鼠胎盘中的mGCMa/1。目前正在对抗体进行详细的鉴定。3)我们使用人类癌症阵列（Clontec）研究了GCMa/1在各种正常和肿瘤组织中的表达。GCMa/1表现出相当有限的表达。在卵巢和胃的部分样品中检测到低表达。有一个来自结肠癌的样品显示出强表达。4)我们从鸡中克隆了一个GCM直向同源物。新的GCM直系同源物在发育卵的胚外区域表达，这表明与哺乳动物GCMa的功能相似。

GCMa/1 is a transcription factor that solely expresses in the placenta. It is required for the development of syncytioblast. Null-mutation of the factor results early embryonic death due to the.We first planned to raise specific antibody for the protein. Polyclonal antibody was raised against hGCMa protein expressed and purified from E. coli. 1)The antibody detected hGCMa/1 expressed in E. coli. and insect cells. It detected authentic hGCMa/1 in normal term placenta and also mGCMa/1 in mouse placenta in Western blotting. The antibody detected hGCMa1 in chorionic villi of the placenta where aromatase and hCG a have been detected. The result further confirms our previous finding that hGCMa/1 is necessary for the expression of these genes (Yamada et al. J.Biol.Chem. 1999 274 32279-32286. We also tried to get mouse monoclonal antibodies against the protein. 2) We got 2 clones that detected hGCMa/1 in E. coli., insect cells, authentic hGCMa/1 in normal term placenta and also mGCMa/1 in mouse placenta in Western blotting. Detailed characterization of the antibodies are currently on-going. 3) We investigated the expression of GCMa/1 in various normal and tumor tissues using human Cancer Array (Clontec). GCMa/1 showed quite limited expression. Low expression was detected in some samples from ovary and stomach. There was one sample from colon cancer which showed strong expression. 4) We cloned a GCM orthologue from chicken. The new GCM ortholog expresses in the extra-embryonic region of developing egg, that suggest similar function to that of mammalian GCMa.