Chimeric MerR-Family Regulators and Logic Elements for the Design of Metal Sensitive Genetic Circuits in Bacillus subtilis

Jasdeep Ghataora, Susanne Gebhard, Bianca Reeksting

Research output: Contribution to journalArticlepeer-review

3 Citations (SciVal)


Whole-cell biosensors are emerging as promising tools for monitoring environmental pollutants such as heavy metals. These sensors constitute a genetic circuit comprising a sensing module and an output module, such that a detectable signal is produced in the presence of the desired analyte. The MerR family of metal-responsive regulators offers great potential for the construction of metal sensing circuits, due to their high sensitivity, tight transcription control, and large diversity in metal-specificity. However, the sensing diversity is broadest in Gram-negative systems, while chassis organisms are often selected from Gram-positive species, particularly sporulating bacilli. This can be problematic, because Gram-negative biological parts, such as promoters, are frequently observed to be nonfunctional in Gram-positive hosts. Herein, we combined construction of synthetic genetic circuits and chimeric MerR regulators, supported by structure-guided design, to generate metal-sensitive biosensor modules that are functional in the biotechnological work-horse species Bacillus subtilis. These chimeras consist of a constant Gram-positive derived DNA-binding domain fused to variable metal binding domains of Gram-negative origins. To improve the specificity of the whole-cell biosensor, we developed a modular “AND gate” logic system based on the B. subtilis two-subunit σ-factor, SigO-RsoA, designed to maximize future use for synthetic biology applications in B. subtilis. This work provides insights into the use of modular regulators, such as the MerR family, in the design of synthetic circuits for the detection of heavy metals, with potentially wider applicability of the approach to other systems and genetic backgrounds.
Original languageEnglish
Pages (from-to)735-749
Number of pages15
JournalACS Synthetic Biology
Issue number3
Early online date11 Jan 2023
Publication statusPublished - 17 Mar 2023

Bibliographical note

Funding Information:
We acknowledge the Engineering and Physical Sciences Research Council (EPSRC; EP/PO2081X/1) and industrial collaborators/partners for funding the Resilient Materials for Life (RM4L) project. J.G. was supported by a University of Bath Leveraged Studentship Award. We thank the technical staff in the Life Sciences Department for key support.

Publisher Copyright:
© 2023 The Authors. Published by American Chemical Society.


  • AND gate
  • biosensor
  • genetic engineering
  • synthetic biology

ASJC Scopus subject areas

  • Biomedical Engineering
  • Biochemistry, Genetics and Molecular Biology (miscellaneous)


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