cDNA cloning of the recepters for the members of TGFbeta superfamily

这些因子是tgf - β超家族的成员，特别是tgf - β被认为在细胞复制和分化、伤口愈合、骨重塑和造血过程中起着关键作用。其中，tgf - β对细胞生长的抑制作用已被许多研究者特别是从癌症研究的角度进行了研究。为了分析这些因子的作用机制，我们尝试对这些因子的受体进行cDNA克隆。我们利用TGFbeta 2型受体的高度同源区域克隆了2-3个克隆。我们将进一步分析这些克隆。另一方面，我们发现TGF β可以改变人肺癌细胞系A549的细胞形态，使其由上皮样细胞转变为成纤维梭形扁平细胞。虽然这一事实已有报道，但也发现TGF β可以转化细胞的形态，并同时抑制转化后的细胞表型，即在软琼脂和单层培养中的生长能力，单层培养中的饱和密度。人们注意到，形态学的改变与转化表型的丧失有关。当CHO-K1细胞暴露于cAMP的衍生物时，也观察到转化的表型被强烈抑制，同时细胞形态也以类似的方式改变。这种现象称为逆变换或再微分。我们提出TGF β引起的效应与反向转化密切相关。此外，我们将分析该超家族的其他成员，即骨形态发生蛋白激活素A所造成的影响。

The factors, which are members of TGFbeta superfamily, especially TGFbeta are thought to be playing key roples in the regulation of cellular replication and defferentiation, wound healing, remodeling of the bone and hoematopoiesis. Among them, inhibitory effect of TGFbeta on the cellular growth has been studied by many investigators especially from the viewpoint of cancer research. The cDNA cloning of the receptors of these factors have been tried in order to analyze the mechanism of these factors. We cloned 2-3 clones using the highly homologous region of the type 2 recepter of TGFbeta. We are going to analyze these clones futher.On the other hand, it was found that TGF beta alter the cellular morphology of the human lung carcinoma cell line A549 from epithelial-like cells to the fibroblastic spindle shaped flat cells. Although this fact is already reported, it was also found that TGF beta can converted the morphology and concomitantly suppress the transformed phenotype of the cells, namely growth ability in the soft agar and in monolayr culture, saturation density in monolayr culture. And it was noticed that the alteration in morphology is related to the loss of the transformed phenotype.When CHO-K1 cells are exposed to the derivatives of cAMP,it was also observed that transformed phenotype is strongly suppressed and concomitantly cell morphology is altered in a similar way. This phenomenon is called reverse transformation or redifferentiation. It is proposed by us that the effect caused by TGF beta is closely related to the reverse transformation. Further, we are going to analyze the effects caused by other members of this superfamily, namely bone morphogenetic protein, activin A.