Journal Article

Light-Dependent Regulation of DEL1 Is Determined by the Antagonistic Action of E2Fb and E2Fc

Berckmans, Barbara, De Veylder, Lieven, Bögre, Laszlo, Lammens, Tim, Magyar, Zoltan, Van Den Daele, Hilde

2011

Overview

Endoreduplication represents a variation on the cell cycle in which multiple rounds of DNA replication occur without subsequent chromosome separation and cytokinesis, thereby increasing the cellular DNA content. It is known that the DNA ploidy level of cells is controlled by external stimuli such as light; however, limited knowledge is available on how environmental signals regulate the endoreduplication cycle at the molecular level. Previously, we had demonstrated that the conversion from a mitotic cell cycle into an endoreduplication cycle is controlled by the atypical E2F transcription factor, DP-E2F-LIKE1 (DEL1), that represses the endocycle onset. Here, the Arabidopsis (Arabidopsis thaliana) DEL1 gene was identified as a transcriptional target of the classical E2Fb and E2Fc transcription factors that antagonistically control its transcript levels through competition for a single E2F cis-acting binding site. In accordance with the reported opposite effects of light on the protein levels of E2Fb and E2Fc, DEL1 transcription depended on the light regime. Strikingly, modified DEL1 expression levels uncoupled the link between light and endoreduplication in hypocotyls, implying that DEL1 acts as a regulatory connection between endocycle control and the photomorphogenic response.

• Publisher: American Society of Plant Biologists
• Subject: antagonists & inhibitors / Arabidopsis / Arabidopsis - genetics / Arabidopsis - radiation effects / Arabidopsis Proteins / Arabidopsis Proteins - antagonists & inhibitors / Arabidopsis Proteins - metabolism / Arabidopsis thaliana / Base Sequence / binding sites / Biological and medical sciences / Cell cycle / Cell division / Cell growth / chromosome segregation / Delicatessens / DNA / DNA replication / E2F Transcription Factors / E2F Transcription Factors - antagonists & inhibitors / E2F Transcription Factors - metabolism / endopolyploidy / Fundamental and applied biological sciences. Psychology / Gene Expression Regulation, Plant / Gene Expression Regulation, Plant - radiation effects / Genes / genetics / Hypocotyl / Hypocotyl - genetics / Hypocotyl - radiation effects / Hypocotyls / Light / metabolism / Models, Biological / Molecular Sequence Data / Mutation / Mutation - genetics / photoperiod / Plant cells / Plant physiology and development / Plants / Plants, Genetically Modified / Ploidies / Promoter Regions, Genetic / Promoter Regions, Genetic - genetics / Protein Binding / Protein Binding - radiation effects / radiation effects / SYSTEMS BIOLOGY, MOLECULAR BIOLOGY, AND GENE REGULATION / transcription factors / Transcription Factors - genetics / Transcription Factors - metabolism / Ubiquitin-Protein Ligases / Ubiquitin-Protein Ligases - metabolism