This chapter describes three different strategies of receptor mutagenesis with their advantages, disadvantages, and limitations. Oligonucleotide-directed mutagenesis using either the Altered Sites� II in vitro mutagenesis system or the GeneTailor� site-directed mutagenesis system can generate base substitutions/deletions/insertions that yield single/multiple amino acid substitutions/deletions/insertions and/or N- or C-terminal truncations in GPCRs. Polymerase chain reaction-based mutagenesis strategies allow substitutions/deletions/insertions of larger domains within GPCRs, creating truncated receptors or receptor chimeras. In addition, some guidelines are given and examples are provided to facilitate design and interpretation of mutational experiments.
