Mitotic replication initiation proteins are not required for pre-meiotic Sphase

Initiation of mitotic DNA replication in eukaryotes requires conserved fact ors, including Cdc18/CDC6 and minichromosome maintenance (MCM) proteins. We show here that these proteins are not essential for meiotic DNA replicatio n or subsequent meiotic divisions in fission yeast. In addition, vegetative replication checkpoint genes are not required for the arrest of meiotic di visions in response to pre-meiotic S-phase delays. Genes essential for othe r aspects of vegetative DNA replication, however, including polymerases and DNA ligase, are also required for premeiotic DNA synthesis. Our results in dicate that the process of replication initiation and checkpoint control ma y be fundamentally different in mitotic and meiotic cells.