The 2.2-kb murine Snail promoter was generated by PCR using a forward primer with an XbaI linker sequence, 5′- TCTAGAATTGTTTGCTGCTGTATGGTCTTC-3′, along with a reverse primer with a BglII linker sequence, 5′- AGATCTGTTGGCCAGAGCGACCTAG- GTAG-3′, and mouse genomic DNA as a template. The PCR product was purified with the Gel Extraction Kit (Qiagen, Valencia, California, United States) and ligated into pCRII-TOPO TA vector (Invitrogen, Carlsbad, California, United States). The promoter was verified by sequencing and digested with XbaI and BglII and subcloned into the pβ-gal BASIC vector (BD Biosciences Clontech, Palo Alto, California, United States). The point mutations in the SMAD binding element was generated with the Quik-Change Kit (Stratagene, La Jolla, California, United States) using the forward primer 5′- GGGCGGGCTTAGGTGTTTTCATTTACTCTTGAGGAAAAGCTTGGC-3′ and the reverse primer 5′- GCTTTT- CCTCAAGAGTAAATGAAAACACCTAAGCCCGCCCTGCCC-3′. The probes for the Snail in situ hybridization were generated against the 3′ UTR by PCR using the forward primer 5′- ACCTTCTCCCGCATGTCCTTGCTCC-3′ and the reverse primer 5′- CTGCTGAGGCATGGTTACAGCTGG-3′, and genomic DNA as a template. The PCR product was gel purified and ligated into pCRII-TOPO TA vector. The pre-LIM domain of Ajuba was generated essentially as described [9], but was fused to GFP by subcloning from the pEGFP-N1 20 vector (BD Biosciences Clontech)