Biotechnology and Bioinformatics (1+1)

6.5.3. Components of a biosensor

6.5.3.1. Receptors

A large number of DNA motifs called response elements located in the regulatory regions of all inducible genes that respond to specific intra- or extra-cellular stimuli have been documented. A signal transduction cascade results in activation of transcription factors that bind to these response elements causing up- or down-regulation of gene expression.

6.5.3.2. Reporters

A reporter gene encodes for a mechanism that produces a detectable cellular response. It determines the sensitivity and detection limits of the biosensor. Specific characteristics are needed for the reporter gene to be used in a biosensor. The gene must have an expression or activity that can be measured using a simple assay and reflects the amount of chemical or physical change. Firefly luciferase is by far the most commonly used of the bioluminescent reporters from the firefly Photinus pyralis.