A method to introduce an internal tag sequence into a Salmonella chromosomal gene

Epitope tags are short peptide sequences that are particularly useful for the characterization of proteins against which no antibody has been developed. Influenza hemagglutinin (HA) tag is one of the most widely used epitope tags as several valuable monoclonal and polyclonal antibodies that can be used in various techniques are commercially available. Therefore, adding a HA tag to a protein of interest is quite helpful to get rapid and cost less information regarding its localization, its expression or its biological function. In this chapter, we describe a process, derived from the Datsenko and Wanner procedure, which allows the introduction of an internal 2HA tag sequence into a chromosomal gene of the bacterial pathogen Salmonella.