This Article Full Text Full Text (PDF) Supplemental Data All Versions of this Article: 20/3/580    most recent tpc.108.058172v1 Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Google Scholar Articles by Pien, S. Articles by Grossniklaus, U. PubMed PubMed Citation Articles by Pien, S. Articles by Grossniklaus, U. Agricola Articles by Pien, S. Articles by Grossniklaus, U.

ARABIDOPSIS TRITHORAX1 Dynamically Regulates FLOWERING LOCUS C Activation via Histone 3 Lysine 4 Trimethylation^[W]

^a Institute of Plant Biology, Zürich-Basel Plant Science Center, University of Zürich, Zurich CH-8008, Switzerland
^b Institut für Pflanzenwissenschaften, Zürich-Basel Plant Science Centre, Eidgenössische Technische Hochschule-Zentrum, Zurich CH-8092, Switzerland
^c Department of Plant Systems Biology, Ghent University/Vlaams Instituut voor Biotechnologie, B-9052, Belgium
^d Department of Cell and Development Biology, John Innes Centre, Norwich NR4 7UH, United Kingdom
^e School of Biological Sciences, University of Nebraska, Lincoln, Nebraska 68588-0118

¹ Address correspondence to pien{at}botinst.uzh.ch.

Trithorax function is essential for epigenetic maintenance of gene expression in animals, but little is known about trithorax homologs in plants. ARABIDOPSIS TRITHORAX1 (ATX1) was shown to be required for the expression of homeotic genes involved in flower organogenesis. Here, we report a novel function of ATX1, namely, the epigenetic regulation of the floral repressor FLOWERING LOCUS C (FLC). Downregulation of FLC accelerates the transition from vegetative to reproductive development in Arabidopsis thaliana. In the atx1 mutant, FLC levels are reduced and the FLC chromatin is depleted of trimethylated, but not dimethylated, histone 3 lysine 4, suggesting a specific trimethylation function of ATX1. In addition, we found that ATX1 directly binds the active FLC locus before flowering and that this interaction is released upon the transition to flowering. This dynamic process stands in contrast with the stable maintenance of homeotic gene expression mediated by trithorax group proteins in animals but resembles the dynamics of plant Polycomb group function.