Postreplication Repair via Covalent Modifications of PCNA

Because previous studies demonstrated that both Radfi and Ubcl3 ubiquitination activities are required for their PRR functions, it is expected that the covalent modification of one or more critical targets by these two ubiquitination complexes signals for their respective PRR activities (Broomfield et aL, 2001). A recent study has clearly pointed to PCNA as such a critical target (Hoege et oL, 2002). 

As discussed elsewhere in this book, PCNA (or Pol30 in S. cerevisiae) is an essential component of the eukaryotic replication machinery. The most 

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