Tg(Mesp1-mCherry)5Mik

The ~165 kbp C57BL/6J mouse bacterial artificial chromosome (BAC) RP24-353L5 contains the entire mesoderm posterior 1 locus (Mesp1) as well as ~23 kbp centromeric flanking sequences (including a portion of the Wdr93 locus) and ~131 kbp distal flanking sequences (including the complete Mesp2, Anpep and Ap3s2 loci). Using homologous recombination/BAC recombineering, a construct containing the mCherry sequence, an SV40 polyadenylation signal, an SV40-puro-pA cassette and flanking vector sequences was all inserted into the ATG start site of the BAC Mesp1 gene (replacing the initiation codon of Mesp1 in exon 1). No other loci on the BAC were altered. mCherry expression is observed in mesodermal cell lineages during early gastrulation, including cardiac mesoderm and is consistent with endogenous Mesp1. (J:101977)