A Ser191 phosphorylation site in exon 1 was mutated to alanine and an FRT flaked neo cassette was inserted in intron 1 via homologous recombination. Flp mediated recombination removed the neo cassette. Immunoblot analysis indicates that protein expression is similar to that of the wild-type allele. Chromatin immunoprecipitation analysis indicates reduced binding activity to some enhancers. (J:218283)