A targeting vector was designed to delete the last 150 nucleotides of exon 11 and all of intron 11. The deletion created an in-frame fusion between codon 608 in exon 11 and codon 659 in exon 12. A floxed neo included in the vector was removed via cre-mediated recombination. Northern and Western blot demonstrated that no lamin A was produced. Lamin C was produced at wild-type levels.