A sigma factor toolbox for orthogonal gene expression in Escherichia coli

Indra Bervoets, Maarten Van Brempt, Katleen Van Nerom, Bob Van Hove, Jo Maertens, Marjan De Mey, Daniel Charlier

Research output: Contribution to journalArticle

42 Citations (Scopus)


Synthetic genetic sensors and circuits enable programmable control over timing and conditions of gene expression and, as a result, are increasingly incorporated into the control of complex and multi-gene pathways. Size and complexity of genetic circuits are growing, but stay limited by a shortage of regulatory parts that can be used without interference. Therefore, orthogonal expression and regulation systems are needed to minimize undesired crosstalk and allow for dynamic control of separate modules. This work presents a set of orthogonal expression systems for use in Escherichia coli based on heterologous sigma factors from Bacillus subtilis that recognize specific promoter sequences. Up to four of the analyzed sigma factors can be combined to function orthogonally between each other and toward the host. Additionally, the toolbox is expanded by creating promoter libraries for three sigma factors without loss of their orthogonal nature. As this set covers a wide range of transcription initiation frequencies, it enables tuning of multiple outputs of the circuit in response to different sensory signals in an orthogonal manner. This sigma factor toolbox constitutes an interesting expansion of the synthetic biology toolbox and may contribute to the assembly of more complex synthetic genetic systems in the future.

Original languageEnglish
Pages (from-to)2133-2144
Number of pages12
JournalNucleic Acids Research
Issue number4
Publication statusPublished - 28 Feb 2018


  • Journal Article


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