Source 1primary paper2023
Toolkit/cryptochromes
cryptochromes
Taxonomy: Mechanism Branch / Component. Workflows sit above the mechanism and technique branches rather than replacing them.
Summary
Cryptochromes are blue/ultraviolet-A light-responsive photoreceptor protein domains, including Arabidopsis thaliana cry1 and cry2 variants, that were incorporated into a yeast optogenetic toolkit. In this toolkit context, cryptochrome variants were used as light-sensitive modules in split transcription factors to optically control transcription.
Usefulness & Problems
Why this is useful
Cryptochrome domains are useful as genetically encoded light inputs for regulating transcription with blue/ultraviolet-A illumination. The cited work specifically extends a yeast optogenetic toolkit by adding cryptochrome variants for split transcription factor designs.
Problem solved
This tool helps solve the need for additional light-sensitive dimerization modules for optogenetic transcription control in yeast. The source evidence supports toolkit expansion with cryptochrome variants, but does not provide detailed comparative performance data.
Taxonomy & Function
Primary hierarchy
Mechanism Branch
Component: A low-level protein part used inside a larger architecture that realizes a mechanism.
Mechanisms
HeterodimerizationTechniques
No technique tags yet.
Target processes
transcriptionInput: Light
Implementation Constraints
The available evidence indicates use in yeast as part of split transcription factor constructs, implying implementation by domain fusion into transcriptional control architectures. Arabidopsis thaliana cry1 and cry2 are named as related cryptochromes mediating blue/ultraviolet-A responses, but construct architecture and cofactor requirements are not described in the supplied evidence.
The supplied evidence does not specify which cryptochrome variant was used in the split transcription factors, nor does it report kinetics, dynamic range, leakiness, or wavelength-response measurements. Independent validation beyond the cited toolkit paper is not provided in the evidence set.
Validation
Cell-freeBacteriaMammalianMouseHumanTherapeuticIndep. Replication
Supporting Sources
Ranked Claims
Cryptochrome and Enhanced Magnet light-sensitive dimerizers were incorporated into split transcription factors.
incorporate these light-sensitive dimerizers into split transcription factors
The yeast optogenetic toolkit was expanded to include variants of cryptochromes and Enhanced Magnets.
We expand the yeast optogenetic toolkit to include variants of the cryptochromes and Enhanced Magnets
Approval Evidence
5 sources16 linked approval claimsfirst-pass slug cryptochromes
We expand the yeast optogenetic toolkit to include variants of the cryptochromes and Enhanced Magnets
Source:
Cryptochromes (CRYs) function as blue light photoreceptors in diverse physiological processes in nearly all kingdoms of life. Over the past several decades, they have emerged as the most likely candidates for light-dependent magnetoreception in animals
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...photoactivatable proteins ... have been developed based on the understanding of plant and microbial photoreceptors including ... cryptochromes...
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Arabidopsis has two related cryptochromes (cry1 and cry2) mediating various blue/ultraviolet-A light responses.
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Two cryptochromes (cry1, cry2) ... have been identified in the model species Arabidopsis thaliana.
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design integrationsupports
Cryptochrome and Enhanced Magnet light-sensitive dimerizers were incorporated into split transcription factors.
incorporate these light-sensitive dimerizers into split transcription factors
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toolkit expansionsupports
The yeast optogenetic toolkit was expanded to include variants of cryptochromes and Enhanced Magnets.
We expand the yeast optogenetic toolkit to include variants of the cryptochromes and Enhanced Magnets
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candidate mechanism summarysupports
Cryptochromes have emerged as the most likely candidates for light-dependent magnetoreception in animals.
Over the past several decades, they have emerged as the most likely candidates for light-dependent magnetoreception in animals
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comparative review scopeneutral
The review examines differences in photochemistry and signal transduction between plant and animal cryptochromes and discusses possible convergent evolution that may point to conserved signaling pathways.
The review primarily focuses on examining differences in photochemistry and signal transduction in plant and animal CRYs, and identifies potential modes of convergent evolution within these independent lineages that may identify conserved signaling pathways.
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evidence conflict summarymixed
Validation of cryptochromes as a magnetosensor is complicated by conflicts between in vitro photochemistry and in vivo behavioral data.
a long history of conflicts between in vitro photochemistry and in vivo behavioral data complicate validation of CRYs as a magnetosensor
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functional role summarysupports
Cryptochromes function as blue light photoreceptors across diverse physiological processes in nearly all kingdoms of life.
Cryptochromes (CRYs) function as blue light photoreceptors in diverse physiological processes in nearly all kingdoms of life.
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review scope summarysupports
The review states that photoactivatable proteins derived from plant and microbial photoreceptors have been developed for optogenetic control of biochemical signals.
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activity regulationsupports
Photoactivated Arabidopsis cryptochromes repress COP1 activity.
Here we show that both photoactivated cryptochromes repress COP1 activity
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causal mechanismsupports
Direct regulation of COP1 by photoactivated cryptochromes is primarily responsible for cryptochrome-mediated blue light regulation of seedling photomorphogenic development and genome expression profile.
this direct regulation is primarily responsible for the cryptochrome-mediated blue light regulation of seedling photomorphogenic development and genome expression profile
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protein interactionsupports
Photoactivated Arabidopsis cryptochromes directly contact COP1.
Here we show that both photoactivated cryptochromes repress COP1 activity through a direct protein-protein contact
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functional role summarysupports
Phototropic bending of the shoot toward unilateral blue light is mediated by phototropin, and cry1, cry2, phyA, and phyB positively regulate the response.
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interaction summarysupports
cry2 and phyB are antagonistic in the induction of flowering.
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interaction summarysupports
In higher plants, natural radiation can simultaneously activate more than one photoreceptor, and certain photoreceptor genes show light-dependent epistasis.
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interaction summarysupports
Under short photoperiods of red and blue light, cry1 and phyB are synergistic, whereas under continuous exposure to the same light field their actions become independent and additive.
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mechanistic hypothesis summarysupports
At least some photoreceptor interactions are likely to result from cross talk of photoreceptor signaling pathways.
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systems level summarysupports
Experiments under natural radiation suggest that photoreceptor interactions create a phototransduction network with emergent properties that provides a more robust system for light perception in plants.
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Comparisons
Source-backed strengths
Cryptochromes are established blue light photoreceptors found across diverse physiological contexts and were sufficiently adaptable to be integrated into a yeast optogenetic toolkit. Their incorporation into split transcription factors indicates utility as light-responsive interaction modules for transcriptional regulation.
Ranked Citations
- 1.