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

Abstract

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.

The enzymatic resolution of 1‐(4‐chlorophenyl)ethylamine by Novozym 435 to prepare a novel triazolopyrimidine herbicide

“…Screening is the key step for selection of suitable biocalysts . Fifty commercial lipases were selected for selective amidation of (R,S)‐1.…”

“…Screening is the key step for selection of suitable biocalysts. 15 Fifty commercial lipases were selected for selective amidation of (R,S)-1. Seven lipases displayed amidation activity and displayed a (R)-stereopreference, leaving the target product an (S)-enantiomer.…”

Development of a Novel Biosensor-Driven Mutation and Selection System via in situ Growth of Corynebacterium crenatum for the Production of L-Arginine

“…The biosensors are mainly based on recognition elements that can respond to specific metabolites, such as TFs (Mannan et al, 2017;Hanko et al, 2018), riboswitches (Blouin et al, 2009), fluorescence resonance energy transfer (FRET) (Zhang et al, 2011), and pressuresensitive promoters (Xie et al, 2015). Among these elements, TFs play a major role in controlling gene expression at the level of transcription, and TFs-based biosensors have been widely applied to obtain high-yield strains by monitoring intracellular metabolite production from a measurable output (Cheng et al, 2018).…”

Fine-tuning biosensor dynamic range based on rational design of cross-ribosome-binding sites in bacteria

“…Genetically encoded biosensors derived from transcription factors responding to small-molecule inducers are receiving increasing research attention 3 . The currently available genetically encoded biosensors usually have the major problem of inappropriate dynamic range 6, 8 . Although many valuable works, such as promoter modification studies, have attempted to tune the dynamic range of biosensors, universality may be difficult to achieve owing to small datasets and insufficient analysis tools.…”