Journal Article

plant-specific cyclin-dependent kinase CDKB1;1 and transcription factor E2Fa-DPa control the balance of mitotically dividing and endoreduplicating cells in Arabidopsis

Magyar, Z, Veylder, L. de, Vlieghe, K, Acosta, J.A.T, Schueren, E. van der, Maes, S, Beemster, G.T.S, Boudolf, V

2004

Overview

Transgenic Arabidopsis thaliana plants overproducing the E2Fa-DPa transcription factor have two distinct cell-specific phenotypes: some cells divide ectopically and others are stimulated to endocycle. The decision of cells to undergo extra mitotic divisions has been postulated to depend on the presence of a mitosis-inducing factor (MIF). Plants possess a unique class of cyclin-dependent kinases (CDKs; B-type) for which no ortholog is found in other kingdoms. The peak of CDKB1;1 activity around the G2-M boundary suggested that it might be part of the MIF. Plants that overexpressed a dominant negative allele of CDKB1;1 underwent enhanced endoreduplication, demonstrating that CDKB1;1 activity was required to inhibit the endocycle. Moreover, when the mutant CDKB1;1 allele was overexpressed in an E2Fa-DPa-overproducing background, it enhanced the endoreduplication phenotype, whereas the extra mitotic cell divisions normally induced by E2Fa-DPa were repressed. Surprisingly, CDKB1;1 transcription was controlled by the E2F pathway, as shown by its upregulation in E2Fa-DPa-overproducing plants and mutational analysis of the E2F binding site in the CDKB1;1 promoter. These findings illustrate a cross talking mechanism between the G1-S and G2-M transition points.

• Publisher: American Society of Plant Biologists
• Subject: Arabidopsis / Arabidopsis - cytology / Arabidopsis - enzymology / Arabidopsis - metabolism / Arabidopsis Proteins / Arabidopsis Proteins - metabolism / Arabidopsis thaliana / Base Sequence / Cell cycle / Cell Cycle Proteins / Cell Cycle Proteins - metabolism / Cell division / Cyclin-Dependent Kinases / Cyclin-Dependent Kinases - metabolism / cytology / DNA / DNA ploidy / DNA Primers / DNA replication / DNA-Binding Proteins / DNA-Binding Proteins - metabolism / E2F Transcription Factors / enzyme activity / enzymology / Epidermal cells / gene expression / gene overexpression / leaf development / Leaves / messenger RNA / metabolism / Mitosis / Plant cells / Plant Leaves / Plant Leaves - cytology / Plant Leaves - enzymology / Plant Leaves - metabolism / Plants / Ploidies / Reverse Transcriptase Polymerase Chain Reaction / Sowing / transcription (genetics) / transcription factors / Transcription Factors - metabolism / Transgenic plants