title: Transcriptional regulation of LUX by CBF1 mediates cold input to the circadian clock in Arabidopsis.
abstract: Circadian clocks allow organisms to anticipate daily changes in the environment to enhance overall fitness. Transcription factors (TFs) play a prominent role in the molecular mechanism but are incompletely described possibly due to functional redundancy, gene family proliferation, and/or lack of context-specific assays. To overcome these, we performed a high-throughput yeast one-hybrid screen using the LUX ARRYHTHMO (LUX) gene promoter as bait against an Arabidopsis TF library. LUX is a unique gene because its mutation causes severe clock defects and transcript maintains high-amplitude cycling in the cold. We report the well-characterized cold-inducible C-repeat (CRT)/drought-responsive element (DRE) binding factor CBF1/DREB1b is a transcriptional regulator of LUX. We show that CBF1 binds the CRT in the LUX promoter, and both genes overlap in temporal and spatial expression. CBF1 overexpression causes upregulation of LUX and also alters other clock gene transcripts. LUX promoter regions including the CRT and Evening Element (EE) are sufficient for high-amplitude transcriptional cycling in the cold, and cold-acclimated lux seedlings are sensitive to freezing stress. Our data show cold signaling is integrated into the clock by CBF-mediated regulation of LUX expression, thereby defining a new transcriptional mechanism for temperature input to the circadian clock.
authors: University of Southern California, Molecular and Computational Biology, Department of Biology Dana and David Dornsife College of Letters, Arts and Sciences, Los Angeles, CA 90089, USA.
authors: Brenda Y
authors: BY
authors: Chow
authors: University of Southern California, Molecular and Computational Biology, Department of Biology Dana and David Dornsife College of Letters, Arts and Sciences, Los Angeles, CA 90089, USA.
authors: Sabrina E
authors: SE
authors: Sanchez
authors: Section of Cell and Developmental Biology, Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA.
authors: Ghislain
authors: G
authors: Breton
authors: Section of Cell and Developmental Biology, Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA.
authors: Jose L
authors: JL
authors: Pruneda-Paz
authors: American University, Department of Biology, Washington, DC 20016, USA.
authors: Naden T
authors: NT
authors: Krogan
authors: University of Southern California, Molecular and Computational Biology, Department of Biology Dana and David Dornsife College of Letters, Arts and Sciences, Los Angeles, CA 90089, USA. Electronic address: alestell@dornsife.usc.edu.
authors: Steve A
authors: SA
authors: Kay
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000378:metabolism*; D057906:Circadian Clocks / Q000502:physiology*; D003080:Cold Temperature; D018506:Gene Expression Regulation, Plant / Q000235:genetics / Q000502:physiology*; D015723:Gene Library; D057166:High-Throughput Screening Assays; D015534:Trans-Activators / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism*; D020798:Two-Hybrid System Techniques
chemical_list: D029681:Arabidopsis Proteins; C104387:CBF1 protein, Arabidopsis; C504848:Lux Arrhythmo protein, Arabidopsis; D015534:Trans-Activators; D014157:Transcription Factors