Quantitative RT-PCR analysis of Eng (A) and Alk1 (B), and Id1 (C)and NOTCH downstream genes [Hey1 (D), Jag1 (E), and Jag2 (F)] in retinal ECs purified from control (SclCreER-negative Eng-iKO, n=6), SclCreER;Eng-iKO (n=6), and SclCreER;Eng-iKO;ALK1-OE (n=6) mice. The mRNA levels of the genes are normalized with actin. One-way ANOVA with Tukey’s correction. All data are means ± SDs.