Figure 1.

Mcl1^EC/ECembryos show a range of phenotypes at E14.5 while surviving adult Mcl1^EC/EC mice do not show deletion of Mcl1 in ECs. (a) Representative flow cytometric analysis of hCD4 expression (a reporter of Mcl1^fl allele recombination) on E10.5 embryo proper and yolk sac ECs from Mcl1^control (n=12, gray lines), Mcl1^EC/+ (n=7, red lines) and Mcl1^EC/EC (n=4, blue lines) embryos. Control genotypes include Mcl1^fl/+;Tie2-Cre^+/+, Mcl1^fl/fl;Tie2-Cre^+/+ and Mcl1^+/+;Tie2-Cre^T/+. Data from three litters. (b) Representative images of Mcl1^control(n=60) and Mcl1^EC/EC (n=18) E14.5 embryos. Data from 18 litters. Yellow arrowhead indicates edema, white arrowhead indicates hemorrhage and blue arrow indicates possible blood-filled lymphatic vessels. Red line demarcates region of dorsal skin used for quantification of vasculature in F and G. Scale bar=2 mm. (c) Representative flow cytometric analysis of hCD4 expression on adult kidney, lung and skeletal muscle ECs from Mcl1^control (n=6, gray line), Mcl1^EC/+ (n=6, red line) and Mcl1^EC/EC (n=6, blue line) mice. Control genotypes include Mcl1^fl/+;Tie2-Cre^+/+, Mcl1^fl/fl;Tie2-Cre^+/+ and Mcl1^+/+;Tie2-Cre^T/+. Data from six litters. (d) Representative genomic PCR result from fluorescence-activated cell sorting sorted kidney ECs isolated from Mcl1^EC/+ (n=3) and Mcl1^EC/EC (n=3) mice. (e) Flow cytometric analysis of hCD4 expression from an E10.5 Mcl1^iEC/+ embryo (n=1, green line) showing inefficient recombination of the conditional allele compared with Mcl1^control (n=12, gray line) and an Mcl1^EC/+ embryo with efficient Mcl1 allele deletion (n=7, red line). (f) Representative images of E14.5 dorsal skin vasculature stained for PECAM1 from Mcl1^control (n=3) and Mcl1^EC/EC (n=4) embryos. Yellow line demarcates avascular region. Scale bar=500 μm. Graph shows quantification of avascular region from Mcl1^control (n=3, open circles) and Mcl1^EC/EC (n=4, closed circles) embryos. (g) Representative images of dorsal skin vasculature quantified for sprout length stained for PECAM1 from Mcl1^control (n=3) and Mcl1^EC/EC (n=4). Yellow lines trace sprouts to nearest branch point. Scale bar=200 μm. Graph shows quantification of mean sprout length per embryo from Mcl1^control (n=3, open circles) and Mcl1^EC/EC (n=4, closed circles) embryos. Mean±S.E.M. *P⩽0.05, Student's two-tailed t-test