Circadian Clock Modulation for Continuous Gene Expression
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Solution Overview
Problem
Current methods for increasing gene expression in cyanobacteria are inefficient for industrial applications, particularly for biofuel production, due to low heterologous expression and limited tools for reprogramming metabolic flux in photosynthetic microbes.
Innovation Solution
Modulating the circadian clock by overexpressing KaiA or KaiC proteins to switch from cycling to constitutive gene expression, enhancing the expression of endogenous and foreign genes such as hydrogenases and human proinsulin, through the use of expression control sequences that regulate clock gene activity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If current methods are used for increasing gene expression in cyanobacteria, then existing expression systems are maintained, but heterologous expression remains low and industrial application is limited
Solution Approach 1:
The patent changes the temporal expression pattern parameter from circadian cycling to constitutive expression by manipulating clock gene activity. This parameter change enables continuous high-level expression of heterologous genes, transforming the system from low-productivity rhythmic expression to high-productivity constant expression suitable for industrial applications
Solution Approach 2:
The patent uses clock genes (kaiA, kaiC) as intermediary targets to achieve control over heterologous gene expression. By modulating the circadian clock through these intermediary genes, the system indirectly controls the expression of target genes, enabling reliable and scalable expression systems for industrial biotechnology
2Productivity
If circadian cycling is maintained, then natural gene expression patterns are preserved, but production efficiency for 24/7 biofuel and pharmaceutical manufacturing is limited
Solution Approach 1:
The patent applies preliminary action by first modulating the circadian clock genes (kaiA or kaiC) to suppress rhythmicity, then subsequently achieving constitutive expression of target genes. This preliminary manipulation of the clock system enables continuous production capability without requiring the organism to maintain natural circadian cycling
Solution Approach 2:
The patent dynamically adjusts the expression regime from fixed circadian cycling to flexible constitutive expression. By using expression control sequences that respond to clock gene modulation, the system transitions from static rhythmic patterns to dynamic continuous expression, enabling 24/7 production of biofuels and pharmaceuticals
Data Source
AI summary
A method of increasing gene expression by manipulating the circadian clock is described that includes transforming a photosynthetic organism to include an expression control sequence that modulates the expression of a clock gene to increase expression of a target gene. Photosynthetic organism having a modified circadian cycle reflecting this method are also described.