MECHANISM OF HUMAN DNA POLYMERASE DELTA, RF-C AND PCNA

人类的复制器官由十几种不同的 proteins. 其中之一是PCNA，一种环状的三聚体， 完全包围着DNA PCNA环可沿着DNA自由滑动， 其功能是结合DNA聚合酶，从而将其长时间保持在DNA上 链DNA合成，一种聚合酶的行为， 来复制长染色体。 “PCNA钳”不会组装到DNA上 就其本身而言，它需要RFC复合体的匹配活动。 RFC是 一种5亚基复合物，识别引物DNA位点和PCNA， ATP水解使PCNA围绕DNA组装。 之后，DNA 聚合酶δ（和DNA聚合酶δ）可以与PCNA组装， DNA的高度进行性合成环。 这项建议是一项密集的 研究PCNA在DNA上组装的机制， 和它与DNA聚合酶δ的行为。 PCNA环如何组装 在这个过程中，ATP的作用将是 测定 此外，RFC复合物如何协调其对PCNA的作用， 将检测Pol δ对同一PCNA环的作用。 期间 在染色体的一条链上的不连续合成，DNA聚合酶 必须能够来和关闭DNA的延伸，许多滞后 链碎片。 如果这种聚合酶通过PCNA钳与DNA结合， 它能回收利用吗？ 聚合酶和聚合酶的再循环机制 PCNA环将被研究。 这些复制蛋白也参与DNA的修复， 细胞周期的调控。 因此，更深入地了解 这些蛋白质功能的分子机制也应该 推进修复和细胞周期控制领域。

The human replication apparatus consists of over a dozen different proteins. Among them is PCNA, a trimer in the shape of a ring that completely encircles DNA. The PCNA ring slides freely along DNA and its function is to bind the DNA polymerase thereby holding it to DNA for long chain DNA synthesis, a behavior one might expect of a polymerase that needs to duplicate long chromosomes. The "PCNA clamp" does not assemble onto DNA by itself, it requires the matchmaking activity of the RFC complex. RFC is a 5 subunit complex that recognizes a primed DNA site and PCNA, and couples ATP hydrolysis to assemble PCNA around the DNA. Afterward, the DNA polymerase delta (and DNA polymerase epsilon) can assemble with the PCNA ring for highly processive synthesis of DNA. This proposal is an intensive investigation into the mechanism underlying the assembly of PCNA on DNA, and its behavior with DNA polymerase delta. How the PCNA ring is assembled around DNA by RFC and the role(s) of ATP in this process will be determined. Also, how the RFC complex coordinates its action on PCNA with the action of Pol delta on the same PCNA ring will be examined. During discontinuous synthesis on one strand of the chromosome, the DNA polymerase must be capable of coming on and off DNA for extension of numerous lagging strand fragments. If this polymerase is tied to DNA by the PCNA clamp, how does it recycle? Mechanisms for recycling of both the polymerase and the PCNA ring will be studied. These replication proteins are also involved in the repair of DNA and in regulation of the cell cycle.. Hence, a deeper understanding of the molecular mechanisms underlying the function of these proteins should also advance the fields of repair and cell cycle control.