HFR1, a putative bHLH transcription factor, mediates both phytochrome A and cryptochrome signalling

Duek, Paula D.; Fankhauser, Christian

doi:10.1046/j.1365-313x.2003.01770.x

Cited by 143 publications

(148 citation statements)

References 52 publications

(114 reference statements)

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“…Among those, HFR1, PRE6/KIDARI, PAR1, and PAR2 encode HLH proteins that function positively in light signaling pathways Fankhauser and Chory, 2000;Duek and Fankhauser, 2003;Hyun and Lee, 2006;Roig-Villanova et al, 2006;Zhou et al, 2014). All four proteins play major roles in shade avoidance response (Roig-Villanova et al, 2007;Lorrain et al, 2008).…”

Section: Discussionmentioning

confidence: 99%

A Negative Feedback Loop between PHYTOCHROME INTERACTING FACTORs and HECATE Proteins Fine-Tunes Photomorphogenesis in Arabidopsis

Zhu

Xin

et al. 2016

Plant Cell

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The phytochrome interacting factors (PIFs), a small group of basic helix-loop-helix transcription factors, repress photomorphogenesis both in the dark and light. Light signals perceived by the phytochrome family of photoreceptors induce rapid degradation of PIFs to promote photomorphogenesis. Here, we show that HECATE (HEC) proteins, another small group of HLH proteins, antagonistically regulate PIFs to promote photomorphogenesis. HEC1 and HEC2 heterodimerize with PIF family members. PIF1, HEC1, and HEC2 genes are spatially and temporally coexpressed, and HEC2 is localized in the nucleus. hec1, hec2, and hec3 single mutants and the hec1 hec2 double mutant showed hyposensitivity to light-induced seed germination and accumulation of chlorophyll and carotenoids, hallmark processes oppositely regulated by PIF1. HEC2 inhibits PIF1 target gene expression by directly heterodimerizing with PIF1 and preventing DNA binding and transcriptional activation activity of PIF1. Conversely, PIFs directly activate the expression of HEC1 and HEC2 in the dark, and light reduces the expression of these HECs possibly by degrading PIFs. HEC2 is partially degraded in the dark through the ubiquitin/26S-proteasome pathway and is stabilized by light. HEC2 overexpression also reduces the light-induced degradation of PIF1. Taken together, these data suggest that PIFs and HECs constitute a negative feedback loop to fine-tune photomorphogenesis in Arabidopsis thaliana.

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Section: Discussionmentioning

confidence: 99%

A Negative Feedback Loop between PHYTOCHROME INTERACTING FACTORs and HECATE Proteins Fine-Tunes Photomorphogenesis in Arabidopsis

Zhu

Xin

et al. 2016

Plant Cell

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“…Therefore, the contribution of the three main groups of photoreceptors to the light-dependent induction of the four candidate genes under hypoxia was tested in double mutants for phototropins (phot1-5 phot2-1; de Carbonnel et al, 2010), cryptochromes (cry2-1 cry1-304; Duek and Fankhauser, 2003), and phytochromes (phyA-211 phyB-9; Cerdán and Chory, 2003). The genes MGD3, MGD2, PAP17, and At5g20790 showed no difference in their expression during normoxic or hypoxic conditions in the photoreceptor mutants compared with the wild type (Supplemental Fig.…”

Section: Phr1 Activity Is Potentially Regulated By a Chloroplast-derimentioning

confidence: 99%

A Shoot-Specific Hypoxic Response of Arabidopsis Sheds Light on the Role of the Phosphate-Responsive Transcription Factor PHOSPHATE STARVATION RESPONSE1

et al. 2014

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Plant responses to biotic and abiotic stresses are often very specific, but signal transduction pathways can partially or completely overlap. Here, we demonstrate that in Arabidopsis (Arabidopsis thaliana), the transcriptional responses to phosphate starvation and oxygen deficiency stress comprise a set of commonly induced genes. While the phosphate deficiency response is systemic, under oxygen deficiency, most of the commonly induced genes are found only in illuminated shoots. This jointly induced response to the two stresses is under control of the transcription factor PHOSPHATE STARVATION RESPONSE1 (PHR1), but not of the oxygen-sensing N-end rule pathway, and includes genes encoding proteins for the synthesis of galactolipids, which replace phospholipids in plant membranes under phosphate starvation. Despite the induction of galactolipid synthesis genes, total galactolipid content and plant survival are not severely affected by the up-regulation of galactolipid gene expression in illuminated leaves during hypoxia. However, changes in galactolipid molecular species composition point to an adaptation of lipid fluxes through the endoplasmic reticulum and chloroplast pathways during hypoxia. PHR1-mediated signaling of phosphate deprivation was also light dependent. Because a photoreceptor-mediated PHR1 activation was not detectable under hypoxia, our data suggest that a chloroplast-derived retrograde signal, potentially arising from metabolic changes, regulates PHR1 activity under both oxygen and phosphate deficiency.

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“…To identify phyA signaling intermediates involved in the regulation of PEX11b, we further examined null mutants of several well-characterized players in the phyA signaling pathway, including the novel nuclear protein FHY1, the homologous nuclear proteins FHY3 and FAR1, the GRAS family member PAT1, and the basic helix-loop-helix (bHLH) transcription factor HFR1 (Hudson et al, 1999;Bolle et al, 2000;Fairchild et al, 2000;Desnos et al, 2001;Wang and Deng, 2002b;Duek and Fankhauser, 2003). After far-red light treatment, the expression of PEX11b in these mutants did not differ significantly from that of the wild type, in contrast to the strongly decreased induction in phyA (Supplemental Fig S2).…”

Section: Light Induces Peroxisome Proliferationmentioning

confidence: 99%

Light Induces Peroxisome Proliferation in Arabidopsis Seedlings through the Photoreceptor Phytochrome A, the Transcription Factor HY5 HOMOLOG, and the Peroxisomal Protein PEROXIN11b

Desai

2008

Plant Physiology

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Peroxisomes are single membrane-delimited subcellular organelles that carry out numerous vital metabolic reactions in nearly all eukaryotes. Peroxisomes alter their morphology, abundance, and enzymatic constituents in response to environmental cues, yet little is known about the underlying mechanisms. In this work, we investigated the regulatory role of light in peroxisome proliferation in Arabidopsis (Arabidopsis thaliana). We provide evidence that light induces proliferation of peroxisomes in Arabidopsis seedlings and that the peroxisomal protein PEX11b plays an important role in mediating this process. The far-red light receptor phytochrome A (phyA) and the bZIP transcription factor HY5 HOMOLOG (HYH) are both required for the up-regulation of PEX11b in the light. We further demonstrate that the phyA and hyh mutants exhibit reduced peroxisome abundance, a phenotype that can be rescued by overexpressing PEX11b in these plants. The HYH protein is able to bind to the promoter of PEX11b, suggesting that the PEX11b gene is a direct target of HYH. We conclude that HYH and PEX11b constitute a novel branch of the phyA-mediated light signaling cascade, which promotes peroxisome proliferation during seedling photomorphogenesis.

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HFR1, a putative bHLH transcription factor, mediates both phytochrome A and cryptochrome signalling

Cited by 143 publications

References 52 publications

A Negative Feedback Loop between PHYTOCHROME INTERACTING FACTORs and HECATE Proteins Fine-Tunes Photomorphogenesis in Arabidopsis

A Negative Feedback Loop between PHYTOCHROME INTERACTING FACTORs and HECATE Proteins Fine-Tunes Photomorphogenesis in Arabidopsis

A Shoot-Specific Hypoxic Response of Arabidopsis Sheds Light on the Role of the Phosphate-Responsive Transcription Factor PHOSPHATE STARVATION RESPONSE1

Light Induces Peroxisome Proliferation in Arabidopsis Seedlings through the Photoreceptor Phytochrome A, the Transcription Factor HY5 HOMOLOG, and the Peroxisomal Protein PEROXIN11b

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