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

GCMa/1是一种仅在胎盘中表达的转录因子。它是合胞细胞发育所必需的。该因子的零突变导致胚胎早期死亡。我们首先计划培养针对该蛋白的特异性抗体。从大肠杆菌中表达并纯化hGCMa蛋白，建立抗hGCMa的多克隆抗体。1)抗体检测大肠杆菌中表达的hGCMa/1。还有昆虫细胞。在正常足月胎盘中检测到真实的hGCMa/1，在小鼠胎盘中检测到mGCMa/1。抗体在已检测到芳香化酶和hCG a的胎盘绒毛膜绒毛中检测到hGCMa1。该结果进一步证实了我们之前的发现，hGCMa/1是这些基因表达所必需的（Yamada et al.）。J.Biol.Chem。1999 274 32279-32286。我们还试图获得针对该蛋白的小鼠单克隆抗体。2)获得了2个在大肠杆菌中检测到hGCMa/1的克隆。Western blotting检测正常足月胎盘中mGCMa/1和小鼠胎盘中mGCMa/1。抗体的详细特征目前正在进行中。3)利用Clontec公司的human Cancer Array检测了GCMa/1在不同正常和肿瘤组织中的表达。GCMa/1表达相当有限。在卵巢和胃的部分样品中检测到低表达。有一个结肠癌样本显示出强烈的表达。4)克隆了鸡的GCM同源物。新的GCM同源物在发育中的卵子的胚外区域表达，表明其功能与哺乳动物的GCMa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.