Crossing Smad9tm1Mwst with Tg(EIIa-cre)C5379Lmgd mice resulted in the removal of exon 3 and the neo cassette. RT-PCR demonstrated the complete deletion of exon 3 in mutants. The deletion putatively results in the deletion of part of the linker and one-third of the MH2 domain of Smad9. (J:99098)