(A) EC-specific deletion of the ADAR1 gene at exon 12–15 is mediated by Cre recombinase, which is driven by cadherin 5 promoter (VE-cadherin). The VEN7 transgenic mouse colony was used in this study. P1, P2, and P3 primers used for genotype analysis are indicated by the arrows. The PCR with mixed primer of these three was used to determine the relative quantity of floxed and deleted ADAR1 alleles. (B) Typical genotyping analysis of founder, F1, and F2 progenies is shown in panel (B). (C) Half of the EC-KO pups (ADAR1 Lox/Lox; Cdh5-Cre+) died within 1 wk after birth, and about 75% died within 3 wk. (D) Cyanotic signs developed in some of the newborn pups, which became severe before they died. Shown here is an EC-KO pup with its wild type littermate at day 2 after birth. (E) Growth was severely retarded in some of the EC-KO pups, which usually cannot survive. (E) Shown in panel (E) is one EC-KO pup with its littermate at two and half week after birth. (F) PCR analysis of ADAR1 gene deletion in ECs isolated from 1 wk old EC-KO pups shows dramatic variation in different mice. (G) ECs isolated from EC-KO mice that survived to 4 wk of age were analyzed for ADAR1 gene deletion by PCR and compared with EC-KO mice at 2 wk of age. No obvious deletion was observed in 4-wk-old mice. (H)
ADAR1 gene deletion in brain, heart (H), lung (Lu), liver (Lv), kidney (K), intestine (In), muscle (M), bone marrow (Bm), and lung ECs was analyzed; ADAR1 deletion was shown to only have occurred in ECs.