A modular autoinduction device for control of gene expression in Bacillus subtilis

• Published in: Metabolic engineering 2020-09, Vol.61, p.326-334
• Main Authors: Corrêa, Graciely Gomes, Lins, Milca Rachel da Costa Ribeiro, Silva, Bruna Fernandes, de Paiva, Gabriela Barbosa, Zocca, Vitoria Fernanda Bertolazzi, Ribeiro, Nathan Vinicius, Picheli, Flavio Pereira, Mack, Matthias, Pedrolli, Danielle Biscaro
• Format: Article
• Language: English
• Subjects: Autoinduction; Bacillus subtilis; Dynamic regulation; LuxR/I; Quorum sensing; Synthetic biology
• ISSN: 1096-7176; 1096-7184
• DOI: 10.1016/j.ymben.2020.03.012

Intense synthesis of proteins and chemicals in engineered microbes impose metabolic burden, frequently leading to reduced growth and heterogeneous cell population. Thus, the correct balance between growth and production is important. Such balance can be engineered through dynamic control of pathways, but few broadly applicable tools are available to achieve this. We present an autonomous control of gene expression mediated by quorum sensing in Bacillus subtilis, able to self-monitor and induce expression without human supervision. Two variations of the induction module and seven of the response module were engineered generating a range of induction folds and strengths for gene expression control. Our strongest response promoter is 2.5 and 3.2 times stronger than the well-characterized promoters PsrfA and Pveg, respectively. We applied our strongest autoinduction device for the production of the vitamin B2. This study presents a toolbox of autoinduction modules for B. subtilis that is modular and tunable. LuxRI quorum sensing based autoinduction device in B. subtilis. Genes luxR and luxI from Aliivibrio fischeri and their respective promoters, called induction module, were inserted as single copy into the genome of B. subtilis. Response modules R1-R7, consisting of one quorum sensing responsive promoter controlling the expression of a gene of interest (or operon of interest), were also inserted as single copy into the genome. The inducer AHL, synthesized by LuxI, diffuses in or out of neighboring cells. When AHL reaches a concentration threshold, it binds to LuxR, which in turn, activates gene expression in the response module. [Display omitted] •A quorum sensing device was developed for inducer-free gene expression in B. subtilis.•Systematic engineering of the quorum sensing device generated a toolbox for autoinduction of gene expression.•The toolbox contains modules that combined generates an array of induction folds and strengths.•The engineered autoinduction device is modular and tunable.