Strategy for epitope tagging the protein-coding region of any gene.

We describe the construction of a plasmid carrying a DNA cassette encoding the influenza virus hemagglutinin (HA1) epitope. Insertion of this cassette into the coding region creates a gene encoding an epitope-tagged protein. The tagged protein can be detected and quantified by using a commercially available anti-HA1 antibody. A one-step procedure introduces the epitope at any restriction site within a gene while maintaining the open reading frame. An example of the application of this technique is presented and the different uses of the cassette are discussed.