Insertion of in-frame sequence tags into proteins using transposons

Several methods based on the use of transposons allow the efficient generation of relatively short (e.g., <35 residues) in-frame insertions in proteins. The analysis of such insertions has provided a simple means to identify sites that tolerate dramatic sequence changes without loss of function ("permissive" sites) and to dissect protein structure-function relationships. In addition, epitope and protease cleavage site "tags" introduced in such insertions have made it possible to analyze the oligomerization state and transmembrane topologies of several proteins. Finally, the DNA inserted by these methods generally carries restriction sites which may facilitate the construction of in-frame deletions and gene fusions encoding a variety of chimeric proteins.