LoxP sites were introduced to introns 4 and 6. An FRT-flanked neomycin cassette was inserted adjacent to the 5' loxP site. Exons 5 and 6 were removed via cre-mediated recombination. The neomycin cassette is present. Deletion of exons 5 and 6 leads to a 311 bp deletion resulting in a frameshift starting at codon 129 of the 1052 codon open reading frame. (J:328905)