High impact information on cdc21

• Orp1p forms protein complexes with both cdc18p and cdc21p in vivo, suggesting that interactions between these proteins and ORC are important for controlling the initiation of DNA replication at the onset of S phase [1].
• Chromatin binding of the fission yeast replication factor mcm4 occurs during anaphase and requires ORC and cdc18 [2].
• Fission yeast cdc21+ belongs to a family of proteins involved in an early step of chromosome replication [3].
• Here we show that the cdc21+ gene product belongs to a family of proteins implicated in DNA replication [3].
• The cdc21 mutant is defective in the mitotic maintenance of some plasmids, like mcm2 and mcm3 [3].

Biological context of cdc21

• The cdc21+ gene of Schizosaccharomyces pombe was originally identified in a screen for cdc mutants affecting S phase and nuclear division [3].
• In the case of cdc 17 the defect is in the ligation of Okazaki fragments. cdc 23 is required for bulk DNA synthesis, whilst cdc 21 may possibly be required for the initiation of a particular sub-set of replicons [4].

References