Open AccessEngineering orthogonal synthetic timer circuits based on extracytoplasmic function σ factors
Author(s) -
Daniela Pinto,
Stefano Vecchione,
Hao Wu,
Marco Mauri,
Thorsten Mascher,
Georg Fritz
Publication year - 2018
Publication title -
nucleic acids research
Language(s) - Uncategorized
Resource type - Journals
SCImago Journal Rank - 9.008
H-Index - 537
eISSN - 1362-4954
pISSN - 0305-1048
DOI - 10.1093/nar/gky614
Subject(s) - biology , synthetic biology , timer , rational design , bacillus subtilis , function (biology) , electronic circuit , benchmark (surveying) , computational biology , rational function , scalability , biological system , computer science , microbiology and biotechnology , bacteria , engineering , mathematics , genetics , telecommunications , geodesy , database , geography , electrical engineering , wireless , mathematical analysis
The rational design of synthetic regulatory circuits critically hinges on the availability of orthogonal and well-characterized building blocks. Here, we focus on extracytoplasmic function (ECF) σ factors, which are the largest group of alternative σ factors and hold extensive potential as synthetic orthogonal regulators. By assembling multiple ECF σ factors into regulatory cascades of varying length, we benchmark the scalability of the approach, showing that these 'autonomous timer circuits' feature a tuneable time delay between inducer addition and target gene activation. The implementation of similar timers in Escherichia coli and Bacillus subtilis shows strikingly convergent circuit behavior, which can be rationalized by a computational model. These findings not only reveal ECF σ factors as powerful building blocks for a rational, multi-layered circuit design, but also suggest that ECF σ factors are universally applicable as orthogonal regulators in a variety of bacterial species.