Abstract
The eukaryotic cell cycle is controlled by the activities of evolutionarily conserved protein kinase complexes, which consist of cyclins and cyclin-dependent kinases (CDKs). In Arabidopsis, the A- and B-type CDKs and the A-, B-, and D-type cyclins are assumed to be crucial for cell cycle progression. Among these regulators, we have focused on a plant-specific B2-type CDK (CDKB2) and its regulatory subunit cyclin D4 (CYCD4).
We have recently proposed that the abundance of CDKB2 protein is regulated not only transcriptionally, but also through proteasome-mediated protein degradation. We have also found that CYCD4s are expressed in the upper region of hypocotyls, and this result coincides with our observation that the CYCD4 overexpression promoted cell division in the stomatal lineage in hypocotyls. For more detailed functional analysis, we are currently crossing T-DNA knockouts and CYCD4-overexpressing plants with mutants which are known to have defects in stomatal development.
