Figure 1.

Strategy for the targeted disruption of the MKK4 gene. The pBSNTK2 vector, the MKK4 targeting vector, the genomic region at the MKK4 locus, and the predicted structure of the mutated MKK4 gene. Restriction enzyme sites are indicated (B, BamHI; R, EcoRI; N, NotI; X, XhoI; Ap, ApaI; Sp, SpeI; Xb, XbaI). The two hatched boxes are MKK4 exons corresponding to the subdomain VII and VIII (amino acid residues 211–268). SIAKT is the sequence (single-letter code) that includes the dual phosphorylation sites that are required for MKK4 activation.