A key role of replication factor C in DNA replication checkpoint function in fission yeast. Nucleic Acids Res

Replication factor C (RF-C) is a five subunit DNA polymerase (Pol) δ/ε accessory factor required at the replication fork for loading the essential processivity factor PCNA onto the 3′-ends of nascent DNA strands. Here we describe the genetic analysis of the rfc2+ gene of the fission yeast Schizosaccharomyces pombe encoding a structural homologue of the budding yeast Rfc2p and human hRFC37 proteins. Deletion of the rfc2+ gene from the chromosome is lethal but does not result in the checkpoint-dependent cell cycle arrest seen in cells deleted for the gene encoding PCNA or for those genes encoding subunits of either Pol δ or Pol ε. Instead, rfc2 ∆ cells proceed into mitosis with incompletely replicated DNA, indicating that the DNA replication checkpoint is inactive under these conditions. Taken together with recent results, these observations suggest a simple model in which assembly of the RF-C complex onto the 3′-end of the nascent RNA–DNA primer is the last step required for the establishment of a checkpoint-competent state