Identification of two cell-cycle-controlling cdc2 gene homologs in Arabidopsis thaliana

The cdc2 gene product (p34^cdc2) has been thought to play a central role in control of the mitotic cell cycle of yeasts and animals. To approach an understanding of the cell-cycle-control system in higher plants, we isolated, from an Arabidopsis thaliana cDNA library, two clones (CDC2a and CDC2b) similar to the Schizosacchawmyces pombe cdc2 gene. Genomic Southern-blot analysis with the CDC2a and CDC2b cDNA probes suggested that the A. thaliana genome contains several additional cdc2-like genes, which together with the CDC2a and CDC2b genes may constitute a CDC2 gene family. The CDC2a cDNA expressed in Sc. pombe corrected the elongated morphology, caused by the temperature-sensitive cdc2-33 mutation, to the normal shapes, indicating that the A. thaliana CDC2a gene product resembles Sc. pombe p34^cdc2 functionally as well as structurally. These results support the view that the cell cycle of higher plants is controlled by an analogue of a p34^cdc2-centered regulatory system like that of yeasts and animals.