Tunable Dynamics in a Multistrain Transcriptional Pulse Generator.

Area of Science:

• Synthetic Biology
• Microbial Consortia
• Genetic Engineering

Background:

• Tuning regulatory components in synthetic biology gene circuits is challenging.
• Synthetic microbial consortia require both intracellular and population-level circuit function.
• Coordinating gene expression across multiple engineered strains presents unique difficulties.

Purpose of the Study:

• To demonstrate that synthetic consortium circuit dynamics can be tuned by manipulating strain fractions.
• To engineer a synthetic microbial consortium exhibiting pulse generation behavior.
• To develop and validate a mathematical model for predicting consortium dynamics based on strain composition.

Main Methods:

• Constructed a three-strain synthetic consortium of engineered *Escherichia coli*.
• Utilized homoserine lactone-mediated intercellular signaling to create a multistrain incoherent type-1 feedforward loop (I1-FFL).
• Varied the relative population fractions of each engineered strain within the consortium.
• Developed a mathematical model to simulate and predict the temporal dynamics of the consortium.

Main Results:

• The engineered consortium functioned as a pulse generator for gene expression.
• The amplitude of gene expression pulses was effectively tuned by adjusting the relative fractions of the constituent strains.
• A mathematical model accurately predicted desired pulse characteristics for various population fractions.
• Experimental results confirmed model predictions, validating the tunability through strain fraction manipulation.

Conclusions:

• Strain fractions within synthetic microbial consortia are a viable method for tuning circuit dynamics.
• Intercellular gene circuits in microbial consortia can be effectively controlled by simple adjustments to initial strain proportions.
• This approach offers a simplified strategy for managing complex behaviors in engineered microbial communities.