This transgene consists of a bacterial artificial chromosome (RP24-236G5 BAC) containing mouse Stat3 that was modified to delete valine 463 from the binding domain. The deletion consists of a 1,163 bp DNA fragment starting with the last codon of Stat3 exon 15 and ending at the 5' end of exon 16. This mutation affects Stat3 DNA binding activity in a dominant negative way. Line 9199 (L1) contains 2 transgene copies.