Display Settings:


Send to:

Choose Destination
See comment in PubMed Commons below
Plant Cell. 2010 Mar;22(3):594-605. doi: 10.1105/tpc.109.072892. Epub 2010 Mar 16.

PSEUDO-RESPONSE REGULATORS 9, 7, and 5 are transcriptional repressors in the Arabidopsis circadian clock.

Author information

  • 1RIKEN Plant Science Center, Plant Productivity Systems Research Group, Tsurumi, Yokohama 230-0045, Japan. nnakamichi@psc.riken.jp


An interlocking transcriptional-translational feedback loop of clock-associated genes is thought to be the central oscillator of the circadian clock in plants. TIMING OF CAB EXPRESSION1 (also called PSEUDO-RESPONSE REGULATOR1 [PRR1]) and two MYB transcription factors, CIRCADIAN CLOCK ASSOCIATED1 (CCA1) and LATE ELONGATED HYPOCOTYL (LHY), play pivotal roles in the loop. Genetic studies have suggested that PRR9, PRR7, and PRR5 also act within or close to the loop; however, their molecular functions remain unknown. Here, we demonstrate that PRR9, PRR7, and PRR5 act as transcriptional repressors of CCA1 and LHY. PRR9, PRR7, and PRR5 each suppress CCA1 and LHY promoter activities and confer transcriptional repressor activity to a heterologous DNA binding protein in a transient reporter assay. Using a glucocorticoid-induced PRR5-GR (glucorticoid receptor) construct, we found that PRR5 directly downregulates CCA1 and LHY expression. Furthermore, PRR9, PRR7, and PRR5 associate with the CCA1 and LHY promoters in vivo, coincident with the timing of decreased CCA1 and LHY expression. These results suggest that the repressor activities of PRR9, PRR7, and PRR5 on the CCA1 and LHY promoter regions constitute the molecular mechanism that accounts for the role of these proteins in the feedback loop of the circadian clock.

[PubMed - indexed for MEDLINE]
Free PMC Article

Images from this publication.See all images (7)Free text

Figure 1.
Figure 2.
Figure 3.
Figure 4.
Figure 5.
Figure 6.
Figure 7.
PubMed Commons home

PubMed Commons

How to join PubMed Commons

    Supplemental Content

    Icon for HighWire Icon for PubMed Central Icon for Faculty of 1000
    Loading ...
    Write to the Help Desk