Tbx18^tm4(cre)Akis

A targeting vector was designed to insert a Cre ORF followed by a PGK-neo cassette flanked by FRT sites into the Tbx18 locus. After homologous recombination the ATG codon of Cre replaced the endogenous Tbx18 start codon. The vector was linearized and electroporated into 129S1/SvImJ ES cells. Clones that underwent homologous recombination correctly were identified by Southern blotting and injected into CD-1 morulae. Chimeric males were obtained and mated to a FLPe deleter line. When mice carrying this allele were crossed with mice carrying the cre reporter allele Gt(ROSA)26Sortm1Sor, cre expression was detected in numerous locations of E12.5 embyros including the epicardium, the interventricular septum and myocardial wall of the left ventricle. (J:147421, J:160473)