Transcription Factor‐Based Biosensors in High‐Throughput Screening: Advances and Applications

The molecular mechanisms that cells use to sense changes in the intra‐ and extracellular environment are increasingly utilized in synthetic biology to build genetic reporter constructs for various applications. Although in nature sensing can be RNA‐mediated, most existing genetically‐encoded biosensors are based on transcription factors (TF) and cognate DNA sequences. Here, the recent advances in the integration of TF‐based biosensors in metabolic and protein engineering screens whereas distinction is made between production‐driven and competitive screening systems for enzyme evolution under physiological conditions are discussed. Furthermore, the advantages and disadvantages of existing TF‐based biosensors are examined with respects to dynamic range, sensitivity, and robustness, and compared to other screening approaches. The application examples discussed in this review demonstrate the promising potential TF‐based biosensors hold as screening tools in laboratory evolution of proteins and metabolic pathways, alike. Robust, high‐throughput (HT) screening methods are of fundamental importance for carrying out successful protein and strain evolution campaigns. The recent advances in the emerging field of transcription factor (TF)‐based biosensor screening discussed in this review serve to demonstrate the promising potential of these genetically‐encoded tools in the context of laboratory evolution.