HFR1 is crucial for transcriptome regulation in the cryptochrome 1-mediated early response to blue light in Arabidopsis thaliana.
Cryptochromes are blue light photoreceptors involved in development and circadian clock regulation. They are found in both eukaryotes and prokaryotes as light sensors. Long Hypocotyl in Far-Red 1 (HFR1) has been identified as a positive regulator and a possible transcription factor in both blue and far-red light signaling in plants. However, the gene targets that are regulated by HFR1 in cryptochrome 1 (cry1)-mediated blue light signaling have not been globally addressed. We examined the transcriptome profiles in a cry1- and HFR1-dependent manner in response to 1 hour of blue light. Strikingly, more than 70% of the genes induced by blue light in an HFR1-dependent manner were dependent on cry1, and vice versa. High overrepresentation of W-boxes and OCS elements were found in these genes, indicating that this strong cry1 and HFR1 co-regulation on gene expression is possibly through these two cis-elements. We also found that cry1 was required for maintaining the HFR1 protein level in blue light, and that the HFR1 protein level is strongly correlated with the global gene expression pattern. In summary, HFR1, which is fine-tuned by cry1, is crucial for regulating global gene expression in cry1-mediated early blue light signaling, especially for the function of genes containing W-boxes and OCS elements.
Zhang
Xiao-Ning
XN
Plant Science Institute, Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania, USA. xnzhang@umd.edu
Wu
Yingjie
Y
Tobias
John W
JW
Brunk
Brian P
BP
Deitzer
Gerald F
GF
Liu
Dongmei
D
D000064:Acclimatization / Q000235:genetics*; D017360:Arabidopsis / Q000235:genetics* / Q000254:growth & development / Q000502:physiology; D029681:Arabidopsis Proteins / Q000502:physiology*; D001483:Base Sequence; D003116:Color; D056931:Cryptochromes; D004251:DNA Transposable Elements / Q000502:physiology; D004268:DNA-Binding Proteins / Q000502:physiology*; D005420:Flavoproteins / Q000235:genetics* / Q000502:physiology; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D008027:Light; D055537:Light Signal Transduction / Q000235:genetics; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D009251:NADPH-Ferrihemoprotein Reductase / Q000235:genetics; D009687:Nuclear Proteins / Q000502:physiology*; D030821:Plants, Genetically Modified; D036226:Seedlings / Q000235:genetics / Q000502:physiology
D029681:Arabidopsis Proteins; D056931:Cryptochromes; D004251:DNA Transposable Elements; D004268:DNA-Binding Proteins; D005420:Flavoproteins; D009251:NADPH-Ferrihemoprotein Reductase; D009687:Nuclear Proteins; C538962:CRY1 protein, Arabidopsis; C414438:At1g02340 protein, Arabidopsis