Loading of PCNA - Sliding Clamp Formation

The binding of the primer recognition complex involves the loading of the proliferating cell nuclear antigen (PCNA). Replication Factor C (RFC) transiently opens the PCNA toroid in an ATP-dependent reaction, and then allows PCNA to re-close around the double helix adjacent to the primer terminus. This leads to the formation of the "sliding clamp" (Tsurimoto et al. 1990, Mossi and Hubscher 1998). In a human telomere replication model, RFC-mediated PCNA loading increases the processivity of telomeric C-strand synthesis, but does not eliminate polymerase delta stalling on the G-rich template (Lormand et al. 2013).<br>Interaction of RTEL1 with PCNA is needed for telomere replication and maintenance of telomere integrity (Vannier et al. 2013).

引物识别复合物的结合过程涉及增殖细胞核抗原（PCNA）的装载。复制因子C（RFC）通过ATP依赖性反应暂时开启PCNA的圆环结构，随后允许PCNA在引物末端相邻的双螺旋周围重新闭合。这一过程导致“滑动钳”结构（Tsurimoto等，1990；Mossi和Hubscher，1998）的形成。在人类端粒复制模型中，RFC介导的PCNA装载增加了端粒C链合成的持续性，但并未消除聚合酶δ在富含G模板上的停滞（Lormand等，2013）。RTEL1与PCNA的相互作用对于端粒复制以及端粒完整性的维持至关重要（Vannier等，2013）。