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

人类复制设备由十几种不同的 蛋白质。其中包括增殖细胞核抗原，它是一种环状三聚体， 完全包围了DNA。增殖细胞核抗原环在DNA上的自由滑动及其 功能是结合DNA聚合酶，从而使其与DNA保持较长时间 链DNA合成，一种人们可能期待的聚合酶行为，需要 复制长染色体。“增殖细胞核抗原夹子”不能装配到DNA上 就其本身而言，它需要RFC复合体的撮合活动。RFC是 识别启动的DNA位点和增殖细胞核抗原的5亚基复合体，以及夫妇 三磷酸腺苷水解物使增殖细胞核抗原聚集在DNA周围。之后，DNA 聚合酶增量(和DNA聚合酶epsilon)可与增殖细胞核抗原组装 用于DNA的高度进行性合成的环。这项建议是一项密集的 研究增殖细胞核抗原在DNA上组装的潜在机制， 以及它在DNA聚合酶三角洲上的行为。增殖细胞核抗原环是如何组装的 在这个过程中，三磷酸腺苷的作用(S)将是 下定决心。此外，RFC复合体如何协调其在增殖细胞核抗原上的作用 我们将研究Pol Delta在相同的增殖细胞核抗原环上的作用。在.期间 在染色体的一条链上的不连续合成，DNA聚合酶 必须能够进出DNA以延长众多滞后时间 链条碎片。如果这个聚合酶通过增殖细胞核抗原夹子连接到DNA上， 它会循环使用吗？聚合酶和蛋白质的循环利用机制 将对增殖细胞核抗原环进行研究。 这些复制蛋白还参与DNA的修复和在 细胞周期的调节..因此，更深入地理解 这些蛋白质功能的分子机制也应该 推进修复和细胞周期调控领域。

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.