Cdh5-CatCh-IRES-lacZ transgenic mice (also called Cdh5-CatCh-IRES-lacZ) were designed in the laboratory of Dr. Michael I. Kotlikoff (Cornell University) as part of Cornell/National Heart Lung Blood Resource for Optogenetic Mouse Signaling (CHROMus). The ~200 kbp C57BL/6J mouse bacterial artificial chromosome (BAC) RP23-453P1 was obtained; containing the entire cadherin 5 locus (Cdh5) as well as ~124 kbp of 5' flanking sequences (including the complete Gm32728, Gm39236 and Gm8748 predicted gene loci) and ~33 kbp of 3' flanking sequences (including a 5' portion of the Bean1 locus). Using homologous recombination/BAC recombineering, a 5640 bp CatCh-IRES-lacZ-pA construct (CatCh, internal ribosome entry site, β-galactosidase and an SV40 polyadenylation signal) was inserted into the ATG start site of the BAC Cdh5 gene (replacing the initiation codon of Cdh5 in exon 2). No other loc i on the BAC were altered. The 11.6 kbp BAC vector (pBACe3.6) contained a chloramphenicol selection cassette. (J:314125)