This transgene consists of the CAG promoter, loxP flanked stop codon, a 0.6 kb dominant-negative mouse Bmpr1a cDNA lacking the intracellular kinase domain (Y176STOP), a 0.5 kb internal ribosomal entry site (IRES), a 3.5 kb lacZ gene containing the nuclear localization signal, and a polyadenylation signal. Upon Cre-mediated excision of the Stop codon, the modified allele expresses the dominant negative Bmpr1a and lacZ in tissues where Cre is expressed. (J:192670)