Gene expression and DNA replication triggered by growth factors and their receptors

生长因子及其受体触发的基因表达和 DNA 复制

基本信息

批准号：
02404086
负责人：
ARAI Ken-ichi
金额：
$ 11.39万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (A)
财政年份：
1990
资助国家：
日本
起止时间：
1990 至 1991
项目状态：
已结题

项目摘要

We intended to clarify the intracellular mechanisms of the cell cycle transition from G1 to S. 1) Control of replication in E. coli : G1 to S phase transition is represented by the initiation of chromosomal DNA replication. The new DNA strand synthesis in E. coli, the most thoroughly studied organism, is initiated by the action of primosome, a protein complex essential for priming DNA templates for DNA polymerase. We demonstrated that two types of primosomes, phiXI74 type (priA-dependent) and ABC type (dnaA-dependent), are functionally interchangeable in the ColEl replication. Furthermore, replication of F, R6K, and Rstl plasmids requires dnaA but not priA, whereas recA-dependent and dnaA-independent stable replicafion in E coli requires priA. We proposed that there are two types of replicons in E. coli, one dependrnt on the ABC primosome, and the other dependent on the phiXI74 type primosome. 2) GI to S transition in yeast : Mating pheromone is a yeast peptide that inhibits the initia … More tion of DNA replicafion, thereby arrests the cell cycle of target cells at Gl phase. We have previously demonstrated that its effect is exerted through a specific membrane receptor and a Gprotein. We further showed that a beta-gamma fusion polypeptide is as active as the natural beta/gamma subunit of the G-protein, so that, as a complex, both subunit are the key elements to introduce the mating pheromone signal. We have been looking for proteins that interact with the core sequence of putative chromosomal replication origins of yeast, which are likely to be the initiation factors for DNA replication. We have found several proteins and purified one of them, 100kD protein, to homogeneity. The CDC7 kinase is implicated to be involved in the initiation of DNA replication in yeast. We have constructed an overproducer of the CDC7 protein, and made antibodies against CDC7. Purification and characterization of these proteins are underway. 3) G1 to S transition in hematopoietic cells : Cytokines are a set of polypeptides that are mainly secreted from activated T cells, and act on various types of cells including hematopoietic cells. They not only support cell's viability and cell cycle progression from Gl to S, but also promote subsequent differentiation. Our research has been focusing on the role of IL-3 and GM-CSF on hematopoietic progenitor cells. Both act on very early progenitor cells to stimulate their proliferation and differentiation. Such similarities in the effects of these factors can be explained by our recent finding that receptors for both cytokines are composed of two polypeptides, alpha and beta, of which beta chain is shared. Analysis of the downstream events initiated upon binding of these cytokines to their receptors are underway. T cells are largely in GO/GI phase during the cell cycle. Upon the activation by antigen, they secrete a number of cytokines including IL-3 and GM-CSF, then they start to initiate DNA replication. We have been analyzing promoter Less

我们打算从G1到S的细胞周期过渡的细胞内机制，由染色体DNA复制的启动来代表。启动DNA模板的蛋白质复合物在colel colel Replication中，我们证明了phixi74类型的类型，phixi74型（依赖PRIA依赖性）和ABC类型（DNAA依赖性）。在大肠杆菌中，我们支撑了大肠杆菌中的复制剂，一个取决于ABC原始体，Phixi74型原始体2）我们先前的靶细胞循环。假定的染色体复制起源的核心序列可能是发现其中几个均一的，它是均一的，Cdc7激酶被mplicsimplicase涉及我们在年中的DNA复制启动。 CDC7蛋白质，并对CDC7产生抗体。随后。我们的Rearch一直集中在IL-3和GM-CSF对造血细胞中的作用。 Beta链是在其受体中启动的，它们是由抗原分泌的，包括IL-3和GM-CSF，然后他们开始分析启动子。