a) Schematic of the Egfl7:eGFP transgene. 5.4kb upstream of exon 1b, containing two ETS response elements, was cloned upstream of the β-globin intron, eGFP cDNA, and poly-adenylation sequence. b) Genotyping of potential founders. Genomic DNA was isolated from tail snips of potential founder pups, and genotyped by PCR for the presence of the eGFP sequence. Eight potential founders were identified. c) Transcript expression in E9.5 line 12 embryos by semi-quantitative RT-PCR. Only those embryos that expressed eGFP by live fluorescence expressed the eGFP transcript by semi-quantitative RT-RCR. d) Live expression of eGFP in a representative transgenic E9.5 embryo. D = dorsal, V = ventral, CP = choroid plexus, ISV = intersomitic vessel(s), BA = branchial arches.