INTERACTIONS OF THE MCM PROTEINS AT REPLICATION ORIGINS

DNA合成的起始是一个复杂的多步骤过程， 需要多个复制启动的协调操作 因素这个过程开始于有序组装一个预- 在G1期期间，在复制起点处的复制复合物（pre-RC）。 在酿酒酵母中的研究表明，前RC由以下组成： 进化上保守的复制起始因子，包括 起源识别复合物（origin recognition complex，ORC）是一种同胞亚基复合物， Mcm 2 -7蛋白，一个由6个同源蛋白组成的家族。启动DNA 合成是由组分的连续磷酸化激活的 通过至少两种Cdk（细胞周期蛋白依赖性激酶）或Cdk-1， 如激酶Cdc 28-Clb和Cdc-7-Dbf 4。DNA合成的起始 复制起点伴随着前RC到后RC的过渡。 伸长复合体当伸长复合物从 在复制起点处，前RC被复制后RC取代。 复合体（RC后），似乎包括ORC，但不包括其他 预RC的已知组件。先前的研究表明，Mcm 10 与Mcm 2 -7蛋白的成员物理相互作用。我们将 研究Mcm 10在装配和拆卸中的多重作用 的前RC和它的作用，在迁移的伸长形式， 与Mcm 2 -7蛋白结合。还将作出重大努力， 致力于分析Mcm 10与 预RC的其他组成部分。这些研究应该提供信息 关于限制DNA合成的机制， 在真核生物中。癌细胞的特征是它们的不受调节的细胞 分裂这项研究解决了一个基本问题，在控制 以酿酒酵母为载体的DNA复制和细胞分裂 模型通过了解正常的细胞过程， DNA复制，这可能是可能阐明的分子基础， 导致癌细胞疾病状态的异常或缺陷。

The initiation of DNA synthesis is a complex multi-step process that requires the coordinated actions of a number of replication initiation factors. This process begins with the ordered assembly of a pre- replication complex (pre-RC) at replication origins during the G1 phase. Studies in Saccharomyces cerevisiae indicate that the pre-RC consists of evolutionarily conserved replication initiation factors that include the origin recognition complex, ORC, a complex of sib subunits, and the Mcm2-7 proteins, a family of six homologous proteins. Initiation of DNA synthesis is activated by the successive phosphorylations of components of the pre-RC by at least two Cdks (cyclin dependent kinases) or Cdk- like kinases, Cdc28-Clb and Cdc-7-Dbf4. Initiation of DNA synthesis at replication origins is accompanied by a transition of the pre-RC to the elongation complex. As the elongation complex migrates away from the replication origin, the pre-RC is replaced by the post-replication complex (post-RC), which appears to include the ORC but not the other known components of the pre-RC. Previous studies showed that Mcm10 physically interacts with members of the Mcm2-7 proteins. We will investigate the multiple roles of Mcm10 in the assembly and disassembly of the pre-RC and its role in the migration of elongation forms in conjunction with the Mcm2-7 proteins. Significant efforts will also be devoted to the analysis of the functional relationship between Mcm10 and other components of the pre-RC. These studies should provide information about the mechanism that restricts DNA synthesis to once per cell cycle in eukaryotes. Cancer cells are characterized by their unregulated cell divisions. This study addresses a fundamental problem in the control of DNA replication and cell division using Saccharomyces cerevisiae as the model. Through understanding of normal cellular processes that regulate DNA replication, it may be possible to elucidate the molecular basis for abnormalities or defects that lead to the disease state in cancer cells.