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Series GSE34897 Query DataSets for GSE34897
Status Public on Jan 15, 2012
Title Gene expression from Inducible TOC1 expression in Arabidopsis seedlings
Organism Arabidopsis thaliana
Experiment type Expression profiling by array
Summary The first described feedback loop of the Arabidopsis circadian clock is based on reciprocal regulation between TOC1 and CCA1/LHY. CCA1 and LHY are MYB transcription factors that bind directly to the TOC1 promoter to negatively regulate its expression. Conversely, the activity of TOC1 has remained less well characterized. Genetic data supports that TOC1 is necessary for the reactivation of CCA1/LHY, but there is little description of its biochemical function. Here we show that TOC1 occupies specific genomic regions in the CCA1 and LHY promoters. Purified TOC1 binds directly to DNA through its CCT domain, which is similar to known DNA binding domains. Chemical induction and transient overexpression of TOC1 in Arabidopsis seedlings cause repression of CCA1/LHY expression demonstrating that TOC1 can repress direct targets, and mutation or deletion of the CCT domain prevents this repression showing that DNA binding is necessary for TOC1 action. Furthermore, we use the Gal4/UAS system in Arabidopsis to show that TOC1 acts as a general transcriptional repressor, and that repression activity is in the Pseudoreceiver (PR) domain of the protein. To identify the genes regulated by TOC1 on a genomic scale, we couple TOC1 chemical induction with microarray analysis and identify new potential TOC1 targets and output pathways. Together these results define the biochemical action of the core clock protein TOC1 and refine our perspective on how plant clocks function.

Keywords: Expression profiling by array
Overall design Wildtype (Col-0) and ALC::TOC1 were sown on Murashige-Skoog with 0.8% agar, stratified for 48 hours and grown in12:12 light:dark(LD) for 12 days and either left in LD or transferred to LL and then grown for one more day before the start of the experiment. Tissue was submerged in Murashige-Skoog media supplemented with 2.5% ethanol or no ethanol (mock) and with 20mM MG132 for 3 hours and harvested at ZT1. Three replicates each of the seedlings were collected and frozen in liquid nitrogen.
Contributor(s) Doherty CJ, Gendron JM, Gross AM, Kay SA, Pruneda-Paz JL
Citation(s) 22315425
Submission date Jan 06, 2012
Last update date Aug 15, 2018
Contact name Colleen J Doherty
Organization name North Carolina State University
Department Biochemistry
Lab Colleen Doherty
Street address 128 Polk Hall CB7622
City Raleigh
State/province NC
ZIP/Postal code 27695-7622
Country USA
Platforms (1)
GPL198 [ATH1-121501] Affymetrix Arabidopsis ATH1 Genome Array
Samples (24)
GSM857259 Col_LL_1_Mock
GSM857260 Col_LL_2_Mock
GSM857261 Col_LL_3_Mock
Affiliated with GSE69995
BioProject PRJNA150181

Download family Format
SOFT formatted family file(s) SOFTHelp
MINiML formatted family file(s) MINiMLHelp
Series Matrix File(s) TXTHelp

Supplementary file Size Download File type/resource
GSE34897_RAW.tar 43.9 Mb (http)(custom) TAR (of CEL)
Raw data provided as supplementary file
Processed data included within Sample table

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