Genome Damage and Stability Centre, University of Sussex, Falmer, Brighton BN1 9RQ, UK.
FEBS Lett. 2011 Sep 16;585(18):2772-9. doi: 10.1016/j.febslet.2011.06.005. Epub 2011 Jun 23.
The cell uses specialised Y-family DNA polymerases or damage avoidance mechanisms to replicate past damaged sites in DNA. These processes are under complex regulatory systems, which employ different types of post-translational modification. All the Y-family polymerases have ubiquitin binding domains that bind to mono-ubiquitinated PCNA to effect the switching from replicative to Y-family polymerase. Ubiquitination and de-ubiquitination of PCNA are tightly regulated. There is also evidence for another as yet unidentified ubiquitinated protein being involved in recruitment of Y-family polymerases to chromatin. Poly-ubiquitination of PCNA stimulates damage avoidance, and, at least in yeast, PCNA is SUMOylated to prevent unwanted recombination events at the replication fork. The Y-family polymerases themselves can be ubiquitinated and, in the case of DNA polymerase η, this results in the polymerase being excluded from chromatin.
细胞使用专门的 Y 家族 DNA 聚合酶或损伤避免机制来复制 DNA 中过去受损的部位。这些过程受到复杂的调节系统的控制，这些系统采用不同类型的翻译后修饰。所有 Y 家族聚合酶都具有泛素结合结构域，可与单泛素化 PCNA 结合，从而实现从复制聚合酶到 Y 家族聚合酶的转换。PCNA 的泛素化和去泛素化受到严格的调控。还有证据表明，另一种尚未鉴定的泛素化蛋白参与了 Y 家族聚合酶向染色质的募集。PCNA 的多泛素化可刺激损伤避免，并且至少在酵母中，PCNA 被 SUMO 化以防止复制叉处发生不必要的重组事件。Y 家族聚合酶本身可以被泛素化，在 DNA 聚合酶 η 的情况下，这会导致聚合酶从染色质中排除。
