Two-Way Riboswitch Reversible Gene Control
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Solution Overview
Problem
Current riboswitches are limited by being one-way switches, specific to a given target gene, and not portable, making them impractical for in vivo applications and lacking versatility in gene regulation.
Innovation Solution
Development of a two-way riboswitch that can be inserted upstream of any target gene, utilizing a theophylline-responsive aptamer domain and a LacI repressor protein system to control gene expression reversibly without changing the growth environment, allowing for the use of trigger molecules to activate or deactivate the riboswitch.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional riboswitches are used, then gene expression can be regulated at the translational level, but the switches are one-way and cannot be turned off once activated
Solution Approach 1:
The patent combines a theophylline-responsive riboswitch with a LacI repressor system to create a two-way control mechanism. The riboswitch controls transcription of the lacI gene, which produces repressor protein that binds to LacI operator sequences to block transcription of the target gene. This merging of riboswitch transcriptional control with LacI translational repression enables reversible gene expression control.
Solution Approach 2:
The LacI repressor protein acts as an intermediary between the riboswitch and the target gene. When the riboswitch is activated by theophylline, it induces expression of the LacI repressor, which then mediates repression of the target gene through binding to operator sequences. This intermediary mechanism enables the two-way control functionality.
2Reliability
If riboswitches are designed for specific target genes, then they can provide precise gene regulation, but they lack portability to other genes
Solution Approach 1:
The patent creates a universal riboswitch system that can regulate any target gene through standardized LacI operator sequences. The riboswitch-LacI-repressor module can be inserted upstream of any target gene, and the repressor binds to universal operator sequences to control transcription. This universal design enables the same riboswitch construct to regulate multiple different target genes.
Solution Approach 2:
The system is segmented into modular components: the theophylline-responsive riboswitch, the lacI gene encoding the repressor protein, and the LacI operator sequences. These modular segments can be independently assembled and inserted upstream of different target genes, enabling portable application across multiple genes while maintaining precise regulation through the specific riboswitch-LacI interaction.
3Adaptability or versatility
If inducible promoters are used, then gene expression can be controlled in response to various inducers, but they are not available for all physically relevant genes
Solution Approach 1:
The LacI repressor protein serves as a universal intermediary that can be induced by the riboswitch and then mediate repression of any target gene containing LacI operator sequences. This intermediary approach replaces the need for gene-specific inducible promoters, as the same LacI-repressor system can regulate multiple different target genes.
Solution Approach 2:
The patent creates a universal gene regulation system where the riboswitch-LacI-repressor module can be applied to any target gene. The standardized components (riboswitch, lacI gene, LacI operators) form a universal system that replaces the need for specific inducible promoters for each target gene, making the system widely available and easily manufacturable.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables reversible and tunable control of gene expression, expanding the applications of riboswitches in scientific studies, medical treatments, and biotechnology by allowing for flexible regulation of gene function without environmental changes.
Implementation Method 1
A riboswitch includes an aptameric region that binds the inducer molecule (ligand), and causes a structural change in the expression platform portion of the mRNA riboswitch
Data Source
Figure 1A~1C
Figure 2A~2C
Figure 3A~3D
AI summary
A regulatable gene expression construct comprising a nucleic acid molecule comprising a two- way riboswitch operably linked to a target sequence. Also provided is a library screening strategy for efficient creation of target-specific riboswitches. A theophylline-repressible and IPTG-inducible riboswitch device achieves portable control of gene expression control in a 'two- way' manner. The default state of target genes is ON; the targets are switched off by adding theophylline, and switched back to the ON-state by adding IPTG without changing growth medium. The riboswitch device regulates gene expression in a portabe, adjustable, and two-way manner with a variety of scientific and biotechnological applications.