Ectopic D-Type Cyclin Expression Induces Not Only DNA Replication but Also Cell Division in Arabidopsis Trichomes

Although the mechanisms controlling the two cell-cycle checkpoints G1-S and G2-M are well studied, it remains elusive how they are linked in higher eukaryotes. In animals, D-type cyclins have been implicated in the control of cell-cycle progression in mitotic as well as in endoreduplicating cells. By contrast, we show that the expression of the D-type cyclin CYCD3;1 in endoreduplicating Arabidopsis trichome cells not only induced DNA replication but also cell divisions.