Source 1primary paper2020Journal of Experimental Botany
Toolkit/CRYPTOCHROME-INTERACTING BASIC HELIX-LOOP-HELIX 1
CRYPTOCHROME-INTERACTING BASIC HELIX-LOOP-HELIX 1
Also known as: CIB1
Taxonomy: Mechanism Branch / Component. Workflows sit above the mechanism and technique branches rather than replacing them.
Summary
CRYPTOCHROME-INTERACTING BASIC HELIX-LOOP-HELIX 1 (CIB1) is an Arabidopsis thaliana basic helix-loop-helix transcription factor that binds DNA and regulates transcriptional programs linked to cell elongation. It also physically interacts with the blue-light receptor CRYPTOCHROME 2 (CRY2) and has been described as promoting flowering.
Usefulness & Problems
Why this is useful
CIB1 is useful as a light-linked transcriptional regulator connecting blue-light receptor interaction with downstream gene expression and developmental outputs in Arabidopsis. The cited evidence specifically supports its role in activating genes involved in cell elongation and placing it within antagonistic HLH/bHLH regulatory circuits.
Problem solved
CIB1 helps define how light and high temperature signals are transduced into transcriptional control of cell elongation in Arabidopsis. The evidence indicates that it functions downstream of PIF4 and is negatively modulated by PAR1 and HFR1 within a two-step HLH/bHLH system.
Taxonomy & Function
Primary hierarchy
Mechanism Branch
Component: A low-level protein part used inside a larger architecture that realizes a mechanism.
Mechanisms
direct transcriptional regulationdna bindingDNA Bindinginhibition of dna binding by hlh/bhlh antagonistsprotein-protein interaction with cry2Techniques
No technique tags yet.
Target processes
transcriptionInput: Light
Implementation Constraints
CIB1 is a plant bHLH transcription factor from Arabidopsis thaliana and is associated with blue-light signaling through physical interaction with CRY2. The evidence supports attention to promoter-level regulation by PIF4 and inhibition by HLH/bHLH antagonists PAR1 and HFR1, but it does not provide construct design, cofactor requirements, or heterologous expression guidance.
The supplied evidence is confined to Arabidopsis biology and does not provide quantitative performance data, structural details, or engineered-use validation. Although CIB1 is described as interacting with CRY2 and promoting flowering, the provided claims do not detail the photobiophysical properties or experimental implementation of that interaction.
Validation
Cell-freeBacteriaMammalianMouseHumanTherapeuticIndep. Replication
Supporting Sources
Ranked Claims
CIB1 activates genes that function in cell elongation.
CIB1 activates genes that function in cell elongation
PIF4 directly regulates CIB1 expression by interacting with the CIB1 promoter.
Furthermore, PIF4 directly regulates CIB1 expression by interacting with its promoter
PAR1 interferes with the DNA binding activity of CIB1, thereby suppressing cell elongation.
PAR1 interferes with the DNA binding activity of CIB1, thus suppressing cell elongation
PAR1 and HFR1 interfere with PIF4 binding to the CIB1 promoter.
PAR1 and HFR1 interfere with PIF4 binding to the CIB1 promoter
CIB1 positively regulates cell elongation in Arabidopsis thaliana under the control of PIF4, PAR1, and HFR1.
Here, we show that in Arabidopsis thaliana, the bHLH transcription factor CRYPTOCHROME-INTERACTING BASIC HELIX-LOOP-HELIX 1 (CIB1) positively regulates cell elongation under the control of PIF4, PAR1, and HFR1.
Two antagonistic HLH/bHLH systems, PIF4-PAR1/HFR1 and CIB1-PAR1, regulate cell elongation in response to light and high temperature.
Hence, two antagonistic HLH/bHLH systems, the PIF4-PAR1/HFR1 and CIB1-PAR1 systems, regulate cell elongation in response to light and high temperature.
Approval Evidence
2 sources7 linked approval claimsfirst-pass slug cryptochrome-interacting-basic-helix-loop-helix-1
the bHLH transcription factor CRYPTOCHROME-INTERACTING BASIC HELIX-LOOP-HELIX 1 (CIB1)
Source:
CRYPTOCHROME-INTERACTING basic helix-loop-helix 1 (CIB1) is a well characterized transcriptional factor which promotes flowering through the physical interaction with the blue light receptor CRYPTOCHROME 2 (CRY2) in Arabidopsis.
Source:
activates gene expression programsupports
CIB1 activates genes that function in cell elongation.
CIB1 activates genes that function in cell elongation
Source:
direct transcriptional regulationsupports
PIF4 directly regulates CIB1 expression by interacting with the CIB1 promoter.
Furthermore, PIF4 directly regulates CIB1 expression by interacting with its promoter
Source:
interferes with dna binding activitysupports
PAR1 interferes with the DNA binding activity of CIB1, thereby suppressing cell elongation.
PAR1 interferes with the DNA binding activity of CIB1, thus suppressing cell elongation
Source:
interferes with promoter bindingsupports
PAR1 and HFR1 interfere with PIF4 binding to the CIB1 promoter.
PAR1 and HFR1 interfere with PIF4 binding to the CIB1 promoter
Source:
regulates biological processsupports
CIB1 positively regulates cell elongation in Arabidopsis thaliana under the control of PIF4, PAR1, and HFR1.
Here, we show that in Arabidopsis thaliana, the bHLH transcription factor CRYPTOCHROME-INTERACTING BASIC HELIX-LOOP-HELIX 1 (CIB1) positively regulates cell elongation under the control of PIF4, PAR1, and HFR1.
Source:
regulatory system modelsupports
Two antagonistic HLH/bHLH systems, PIF4-PAR1/HFR1 and CIB1-PAR1, regulate cell elongation in response to light and high temperature.
Hence, two antagonistic HLH/bHLH systems, the PIF4-PAR1/HFR1 and CIB1-PAR1 systems, regulate cell elongation in response to light and high temperature.
Source:
conservationsupports
CIB-dependent regulation of flowering time is evolutionarily conserved across different plant species.
implying that CIBs dependent regulation of flowering time is an evolutionarily conserved mechanism in different plant species
Source:
Comparisons
Source-backed strengths
The evidence identifies CIB1 as a well-characterized transcription factor and supports direct involvement in gene activation programs for cell elongation. Its regulatory context is mechanistically specified: PIF4 directly regulates CIB1 expression through the CIB1 promoter, and PAR1 interferes with CIB1 DNA binding activity.
Ranked Citations
- 1.