LWD-TCP complex activates the morning gene CCA1 in Arabidopsis

Jing Fen Wu, Huang Lung Tsai, Ignasius Joanito, Yi Chen Wu, Chin Wen Chang, Yi Hang Li, Ying Wang, Jong Chan Hong, Jhih-Wei Chu, Chao Ping Hsu, Shu Hsing Wu*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

54 Scopus citations


A double-negative feedback loop formed by the morning genes CIRCADIAN CLOCK ASSOCIATED1 (CCA1)/LATE ELONGATED HYPOCOTYL (LHY) and the evening gene TIMING OF CAB EXPRESSION1 (TOC1) contributes to regulation of the circadian clock in Arabidopsis. A 24-h circadian cycle starts with the peak expression of CCA1 at dawn. Although CCA1 is targeted by multiple transcriptional repressors, including PSEUDO-RESPONSE REGULATOR9 (PRR9), PRR7, PRR5 and CCA1 HIKING EXPEDITION (CHE), activators of CCA1 remain elusive. Here we use mathematical modelling to infer a co-activator role for LIGHT-REGULATED WD1 (LWD1) in CCA1 expression. We show that the TEOSINTE BRANCHED 1-CYCLOIDEA-PCF20 (TCP20) and TCP22 proteins act as LWD-interacting transcriptional activators. The concomitant binding of LWD1 and TCP20/TCP22 to the TCP-binding site in the CCA1 promoter activates CCA1. Our study reveals activators of the morning gene CCA1 and provides an action mechanism that ensures elevated expression of CCA1 at dawn to sustain a robust clock.

Original languageEnglish
Article number13181
Number of pages10
JournalNature Communications
StatePublished - 13 Oct 2016

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