Exon 2 was replaced with a SA-Betagal PGK-neo cassette such that the remaining open reading frame would be out of frame. Exon 2 encodes a 144 amino acid stretch containing the 14-3-3 binding domain and the WW domain. A western blot of protein extracts from mouse embryonic fibroblasts with a C-terminal antibody confirmed the absence of protein expression. (J:125326)