Project description:Sun-loving plants have the ability to detect and avoid shading through sensing of both blue and red light wavelengths. Higher plant cryptochromes (CRYs) control how plants modulate growth in response to changes in blue light. For growth under a canopy, where blue light is diminished, CRY1 and CRY2 perceive this change and respond by directly contacting two bHLH transcription factors, PIF4 and PIF5. These factors are also known to be controlled by phytochromes, the red/far-red photoreceptors; however, transcriptome analyses indicate that the gene regulatory programs induced by the different light wavelengths are distinct. Our results indicate that CRYs signal by modulating PIF activity genome-wide, and that these factors integrate binding of different plant photoreceptors to facilitate growth changes under different light conditions. We performed whole-genome chromatin immunoprecipitation with sequencing (ChIP-Seq) analysis on 5 day old Flash-CRY2, PIF4-Flash and PIF5-Flash treated in low blue-light for 16h.
Project description:FelixGarza2017 - Blue Light Treatment of
Psoriasis (simplified)
This model is described in the article:
A Dynamic Model for
Prediction of Psoriasis Management by Blue Light
Irradiation.
Félix Garza ZC, Liebmann J,
Born M, Hilbers PA, van Riel NA.
Front Physiol 2017; 8: 28
Abstract:
Clinical investigations prove that blue light irradiation
reduces the severity of psoriasis vulgaris. Nevertheless, the
mechanisms involved in the management of this condition remain
poorly defined. Despite the encouraging results of the clinical
studies, no clear guidelines are specified in the literature
for the irradiation scheme regime of blue light-based therapy
for psoriasis. We investigated the underlying mechanism of blue
light irradiation of psoriatic skin, and tested the hypothesis
that regulation of proliferation is a key process. We
implemented a mechanistic model of cellular epidermal dynamics
to analyze whether a temporary decrease of keratinocytes
hyper-proliferation can explain the outcome of phototherapy
with blue light. Our results suggest that the main effect of
blue light on keratinocytes impacts the proliferative cells.
They show that the decrease in the keratinocytes proliferative
capacity is sufficient to induce a transient decrease in the
severity of psoriasis. To study the impact of the therapeutic
regime on the efficacy of psoriasis treatment, we performed
simulations for different combinations of the treatment
parameters, i.e., length of treatment, fluence (also referred
to as dose), and intensity. These simulations indicate that
high efficacy is achieved by regimes with long duration and
high fluence levels, regardless of the chosen intensity. Our
modeling approach constitutes a framework for testing diverse
hypotheses on the underlying mechanism of blue light-based
phototherapy, and for designing effective strategies for the
treatment of psoriasis.
This model is hosted on
BioModels Database
and identified by:
BIOMD0000000695.
To cite BioModels Database, please use:
Chelliah V et al. BioModels: ten-year
anniversary. Nucl. Acids Res. 2015, 43(Database
issue):D542-8.
To the extent possible under law, all copyright and related or
neighbouring rights to this encoded model have been dedicated to
the public domain worldwide. Please refer to
CC0
Public Domain Dedication for more information.
Project description:Sun-loving plants have the ability to detect and avoid shading through sensing of both blue and red light wavelengths. Higher plant cryptochromes (CRYs) control how plants modulate growth in response to changes in blue light. For growth under a canopy, where blue light is diminished, CRY1 and CRY2 perceive this change and respond by directly contacting two bHLH transcription factors, PIF4 and PIF5. These factors are also known to be controlled by phytochromes, the red/far-red photoreceptors; however, transcriptome analyses indicate that the gene regulatory programs induced by the different light wavelengths are distinct. Our results indicate that CRYs signal by modulating PIF activity genome-wide, and that these factors integrate binding of different plant photoreceptors to facilitate growth changes under different light conditions.
Project description:Cryptochromes (CRYs) is known as the key blue light receptors that promote photomorphogenesis in Arabidopsis, but to date, the underlying mechanisms are still not fully understood. Through interrogating the CRY2 interactome, we identified MOS4-ASSOCIATED COMPLEX subunits 3A and 3B (MAC3A and MAC3B) as blue light-independent CRY2 interacting partners. MAC3A/B proteins could be assembled into liquid nuclear condensates of CRYs in a blue light-dependent manner. Hypocotyl elongation is markedly repressed in mac3ab double knock-out mutants under various light conditions, which uncovers a previously unknown role of MAC3A/B as negative regulators in plant photomorphogenesis. Our results also uncover the noncanonical activities of MAC3A as the DNA-binding proteins that regulate transcription. Genome-wide mapping of MAC3A-binding sites reveals that blue light facilitates the binding of MAC3A to its targets, which is weakened in cry1cry2 mutants, suggesting that CRYs may enhance MAC3A activities in blue light to negatively influence photomorphogenesis. Interestingly, we observe that the genomic binding sites of MAC3A and HY5 are largely overlapped, and physical interactions between MAC3A and HY5 are detected as well. In addition, the in vitro DNA-binding assay shows that both proteins compete for the same DNA probe. These results indicate that MAC3A may antagonize the function of HY5 by competing for the common binding sites across the genome. Taken together, we propose that cryptochromes may fine-tune Arabidopsis photomorphogenesis by balancing the positive and negative effects on HY5 activities.