The Phox2b coding sequence was inserted upstream of exon 1 along with a floxed neo cassette which was later removed by cre-mediated recombination following a cross to Tg(ACTB-cre)1Nagy mice. The insertion creates a fusion protein. Southern blot analysis and PCR genotyping were used to confirm the insertion. Immunohistochemistry was used to confirm the alteration in expression patterns.