Figure 3.

Deletion of Mcl1 results in increased EC apoptosis in Mcl1^iEC/iEC retinas at P5. (a) Representative image of apoptotic retina EC. Yellow arrowhead indicates apoptotic EC. PECAM1 (green), Collagen IV (red), active caspase 3 (gray). Scale bar=30 μm. (b) Total apoptotic ECs per retina relative to vascular surface area. (c) Representative examples of regressing vessels in Mcl1^control and Mcl1^iEC/iEC retinas. Yellow arrowheads indicate regressing vessels. Overlay shows collagen IV (red) and PECAM1 (green). Scale bar=50 μm. (d and e) Vessel regression, determined by the ratio of PECAM1-positive vessel segments to collagen IV-positive vessel segments in the venous remodeling zone (d) and in the sprouting zone (e). All data are presented as mean±S.E.M. from Mcl1^control (n=5, open circles), Mcl1^iEC/+ (n=5, gray circles) and Mcl1^iEC/iEC (n=6, closed circles) retinas. Data from six litters. Not significant (NS): P>0.05; ***P⩽0.001; ****P⩽0.0001, one-way ANOVA with Tukey's post hoc multiple comparison test. Control genotypes in each population include Mcl1^fl/+;Cdh5(PAC)-creERT2^+/+, Mcl1^fl/fl; Cdh5(PAC)-creERT2^+/+ and Mcl1^+/+; Cdh5(PAC)-creERT2^T/+