Zn2+-inducible expression platform for Synechococcus sp. strain PCC 7002 based on the smtA promoter/operator and smtB repressor

Adam A. Pérez, John P. Gajewski, Bryan H. Ferlez, Marcus Ludwig, Carol S. Baker, John H. Golbeck, Donald A. Bryant

Research output: Contribution to journalArticle

7 Scopus citations


Synechococcus sp. strain PCC 7002 has been gaining significance as both a model system for photosynthesis research and for industrial applications. Until recently, the genetic toolbox for this model cyanobacterium was rather limited and relied primarily on tools that only allowed constitutive gene expression. This work describes a two-plasmid, Zn2+-inducible expression platform that is coupled with a zurA mutation, providing enhanced Zn2+ uptake. The control elements are based on the metal homeostasis system of a class II metallothionein gene (smtA7942) and its cognate SmtB7942 repressor from Synechococcus elongatus strain PCC 7942. Under optimal induction conditions, yellow fluorescent protein (YFP) levels were about half of those obtained with the strong, constitutive phycocyanin (cpcBA6803) promoter of Synechocystis sp. strain PCC 6803. This metal-inducible expression system in Synechococcus sp. strain PCC 7002 allowed the titratable gene expression of YFP that was up to 19-fold greater than the background level. This system was utilized successfully to control the expression of the Drosophila melanogaster β-carotene 15,15'- dioxygenase, NinaB, which is toxic when constitutively expressed from a strong promoter in Synechococcus sp. strain PCC 7002. Together, these properties establish this metal-inducible system as an additional useful tool that is capable of controlling gene expression for applications ranging from basic research to synthetic biology in Synechococcus sp. strain PCC 7002.

Original languageEnglish (US)
Article numbere02491-16
JournalApplied and environmental microbiology
Issue number3
StatePublished - Jan 1 2017


All Science Journal Classification (ASJC) codes

  • Biotechnology
  • Food Science
  • Applied Microbiology and Biotechnology
  • Ecology

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