CELL-CYCLE CONTROL IN ARABIDOPSIS

Although the basic mechanism of cell cycle control is conserved among eukaryotes, its regulation differs in each type of organism. Plants ha ve unique developmental Features that distinguish them from other euka ryotes. These include the absence of cell migration, the formation of organs throughout the entire life-span from specialized regions called meristems, and the potency of non-dividing cells to re-enter the cell cycle. The study of plant cell cycle control genes is expected to con tribute to the understanding of these unique developmental phenomena. The principal regulators of the eukaryotic cell cycle, the cyclin-depe ndent kinases (CDKs) and cyclins, are conserved in plants. This review focuses on cell cycle regulation in the plant Arabidopsis thaliana. W hile expression of one Arabidopsis CDK gene, Cdc2aAt, was positively c orrelated with the competence of cells to divide, expression of a mito tic-like cyclin, cyclAt, was almost exclusively confined to dividing c ells. The expression of the Arabidopsis delta-type cyclins appears to be an early stage in the response of plant cells to external and inter nal stimuli. (C) 1996 Annals of Botany Company.