Exon2 of Ube3a was replaced with a cassette containing Hprt exons1-2, a loxP site, and a neomycin selection cassette. On the same chromosome, part of Gabrb3 exon 1 and all of exon 2 were replaced by a cassette containing Hprt exons 3-9, another loxP site and a puromycin selection cassette. Properly targeted ES cells were then subjected to transient cre expression. Excision of sequence between Gabrb3 and Ube3a resulted in the creation of a complete Hprt gene that was then used to select for the desired deletion event. The deleted interval extended from 64846987 bp to 66527319 bp) based on the NCBI Build 37 assembly and includes Atp10a. (J:164010)