Temporal repression of core circadian genes is mediated through EARLY FLOWERING 3 in Arabidopsis. (2011)

First Author: Dixon LE

Abstract

The circadian clock provides robust, ~24 hr biological rhythms throughout the eukaryotes. The clock gene circuit in plants comprises interlocking transcriptional feedback loops, reviewed in [1], whereby the morning-expressed transcription factors CIRCADIAN CLOCK-ASSOCIATED 1 (CCA1) and LATE ELONGATED HYPOCOTYL (LHY) repress the expression of evening genes, notably TIMING OF CAB EXPRESSION 1 (TOC1). EARLY FLOWERING 3 (ELF3) has been implicated as a repressor of light signaling to the clock [2, 3] and, paradoxically, as an activator of the light-induced genes CCA1 and LHY [4, 5]. We use cca1-11 lhy-21 elf3-4 plants to separate the repressive function of ELF3 from its downstream targets CCA1 and LHY. We further demonstrate that ELF3 associates physically with the promoter of PSEUDO-RESPONSE REGULATOR 9 (PRR9), a repressor of CCA1 and LHY expression, in a time-dependent fashion. The repressive function of ELF3 is thus consistent with indirect activation of LHY and CCA1, in a double-negative connection via a direct ELF3 target, PRR9. This mechanism reconciles the functions of ELF3 in the clock network during the night and points to further effects of ELF3 during the day.

Bibliographic Information

Digital Object Identifier: http://dx.doi.org/10.1016/j.cub.2010.12.013

PubMed Identifier: 21236675

Publication URI: http://europepmc.org/abstract/MED/21236675

Type: Journal Article/Review

Volume: 21

Parent Publication: Current biology : CB

Issue: 2

ISSN: 0960-9822