Identification of novel cyclin-dependent kinases interacting with the CKS1protein of Arabidopsis

The SUC1/CKS1 proteins interact with cyclin-dependent kinases (CDKs) and pl ay an essential, but yet not entirely resolved, role in the regulation of t he cell cycle. With the Arabidopsis thaliana CKS1At: protein as bait in a t wo-hybrid screen. two novel Arabidopsis CDKs, Arath;CDKB1;2 and Arath;CDKB2 ;1, were isolated. A closely related homologue of Arath;CDKB2;1 was discove red in the databases and was nominated Arath;CDKB2;2. Transcript analysis o f the five known Arath;CDKA and Arath;CDKB genes revealed that they all had the highest expression in flowers and cell suspensions. Differences in the expression patterns in roots, leaves and stems suggest unique roles for ea ch CDK.