Mutational analysis of two Arabidopsis thaliana cyclin-dependent kinases in fission yeast

We have analyzed five mutant alleles of two cyclin-dependent kinases from A rabidopsis thaliana, CDC2aAt and CDC2bAt, in Schizosaccharomyces pombe. Two of the five mutant alleles produced similar phenotypes for both cyclin-dep endent kinases, The other three mutants caused phenotypes dependent on the particular cyclin-dependent kinase, Of all the mutant alleles, only two wer e found to possess a detectable kinase activity. Our mutational analysis le nds further support for CDC2aAt being the true orthologue of the yeast cdc2 , CDC2bAt, even though quite divergent from S, pombe cdc2, still retains th e ability to interact,vith at least some essential cell cycle regulators, s uggesting some functional homology with the yeast protein, Additionally, se demonstrated that the three amino acid deletion in the DL50 mutants result s in the loss of the ability to interact with the suc1/CKS1 proteins, (C) 1 999 Federation of European Biochemical Societies.