A modular synthetic device to calibrate promoters

TL;DR

This paper presents a modular synthetic genetic circuit designed to calibrate and characterize the relative strength of sensing promoters, with analysis showing key parameters for optimal performance and rapid response within two hours.

Contribution

A novel, modular, and simple genetic calibrator device based on a single cell, capable of rapid and sensitive promoter characterization.

Findings

Sensitivity analysis identified key parameters for device performance.

The device can produce detectable signals in less than two hours.

The design is adaptable for various biological contexts.

Abstract

In this contribution, a design of a synthetic calibration genetic circuit to characterize the relative strength of different sensing promoters is proposed and its specifications and performance are analyzed via an effective mathematical model. Our calibrator device possesses certain novel and useful features like modularity (and thus the possibility of being used in many different biological contexts), simplicity, being based on a single cell, high sensitivity and fast response. To uncover the critical model parameters and the corresponding parameter domain at which the calibrator performance will be optimal, a sensitivity analysis of the model parameters was carried out over a given range of sensing protein concentrations (acting as input). Our analysis suggests that the half saturation constants for repression, sensing and difference in binding cooperativity (Hill coefficients) for repression are the key to the performance of the proposed device. They furthermore are determinant for the sensing speed of the device, showing that it is possible to produce detectable differences in the repression protein concentrations and in turn in the corresponding fluorescence in less than two hours. This analysis paves the way for the design, experimental construction and validation of a new family of functional genetic circuits for the purpose of calibrating promoters.