Transcription Factor Engineering for High-Throughput Strain Evolution and Organic Acid Bioproduction: A Review.

Jia-Wei Li,Hui Wu,Yun-Peng Bai,Xiao-Yan Zhang

doi:10.3389/fbioe.2020.00098

Abstract

Metabolic regulation of gene expression for the microbial production of fine chemicals, such as organic acids, is an important research topic in post-genomic metabolic engineering. In particular, the ability of transcription factors (TFs) to respond precisely in time and space to various small molecules, signals and stimuli from the internal and external environment is essential for metabolic pathway engineering and strain development. As a key component, TFs are used to construct many biosensors in vivo using synthetic biology methods, which can be used to monitor the concentration of intracellular metabolites in organic acid production that would otherwise remain “invisible” within the intracellular environment. TF-based biosensors also provide a high-throughput screening method for rapid strain evolution. Furthermore, TFs are important global regulators that control the expression levels of key enzymes in organic acid biosynthesis pathways, therefore determining the outcome of metabolic networks. Here we review recent advances in TF identification, engineering, and applications for metabolic engineering, with an emphasis on metabolite monitoring and high-throughput strain evolution for the organic acid bioproduction.

Highlights

In nature, transcription factors (TFs) control the rate of gene transcription by recognizing specific DNA sequences, regulating expression of the genome
In addition to the normal biological and physiological roles that TFs play in human cells, they can be used as building blocks and regulatory tools in metabolic engineering and synthetic biology (Yadav et al, 2012; Shi et al, 2018; Yang et al, 2019)
We will summarize strategies for identifying new TFs and review the use of TFs as biosensors for monitoring metabolites in vivo and performing high-throughput screening for overproducers, which are important methods used to obtain a strain with the desired phenotype from a library of mutants containing a wide variety of genomic alterations

Summary

INTRODUCTION

Transcription factors (TFs) control the rate of gene transcription by recognizing specific DNA sequences, regulating expression of the genome. Functional screening is used to identify novel TFs that can be engineered in host cells to control the expression of key enzymes in biosynthetic gene clusters (BGCs) (Liu et al, 2013). Researchers have designed and optimized many biosynthetic pathways for natural products (Yadav et al, 2012), such as artemisinin (Paddon and Keasling, 2014) When constructing such pathways, over-expressing positive regulators or knocking down/out negative. We will summarize strategies for identifying new TFs and review the use of TFs as biosensors for monitoring metabolites in vivo and performing high-throughput screening for overproducers, which are important methods used to obtain a strain with the desired phenotype from a library of mutants containing a wide variety of genomic alterations

METHODS

Findings

CONCLUSION AND PERSPECTIVE