lacZ Reporter System as a Tool to Study Virulence Gene Regulation in Bacterial Pathogens

  • Gili Aviv
  • Ohad Gal-MorEmail author
Part of the Methods in Molecular Biology book series (MIMB, volume 1734)


β-galactosidase assay has been established as one of the most widely used reporters and can be effectually exploited to study promoter activity of Salmonella and other pathogens under various conditions. This method includes a preliminary stage of fusing the target promoter to a promoter-less lacZ gene encoding for the enzyme β-galactosidase. Supplementation of the synthetic ONPG substrate results in the accumulation of a chromogenic product proportionally to the activity of the fused promoter. Here we demonstrate the usage of this reporter system to study the regulation of the Salmonella Type three secretion system effector gene sseL in S. Typhimurium [1].

Key words

Beta-galactosidase (β-gal) lacZ Lactose operon O-nitrophenyl-β-d-galactoside (ONPG) Reporter Gene regulation 


Funding Information

The research in Gal-Mor lab is supported by a grant number 1096.39.11/2010 from the German-Israeli Foundation for Scientific Research and Development (GIF); by a grant number 999/14 from the Israel Science Foundation (ISF) and by grant number 3-0000-12435 from Infect-ERA and the Chief Scientist’s Bureau in the Israeli Ministry of Health.


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Copyright information

© Springer Science+Business Media, LLC 2018

Authors and Affiliations

  1. 1.The Infectious Diseases Research LaboratorySheba Medical CenterTel-Hashomer, Ramat GanIsrael
  2. 2.Department of Clinical Microbiology and Immunology, Sackler Faculty of MedicineTel Aviv UniversityTel AvivIsrael

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