Exon 3 was targeted with a G>A mutation changing codon 106 from arginine to glutamine (p.Arg106Gln or p.R106Q) in the DNA-binding domain of the encoded peptide. An FRT site flanked neomycin resistance gene cassette that was inserted into intron 3 was subsequently removed through flp-mediated recombination. This allele mimics a human mutation associated with Rett syndrome. (J:252906)