Fig. 3.

Endothelial-restricted ablation of Fkbp1a using Tie2-cre transgenic mice. (A) Dual immunofluorescence and PCR analyses to confirm the genetic ablation of Fkbp1a in developing endocardial/endothelial cells at E12.5. Representative confocal images of heart sections are co-stained with Alexa Fluor 647-conjugated anti-Fkbp1a antibody (red) and Alexa Fluor 488-conjugated anti-CD31 antibody (green). There is a significant reduction of Fkbp1a in the CD31-positive endothelial cells in Fkbp1a^flox/-:Tie2-cre hearts. Beneath is shown a diagnostic genomic PCR analysis of DNA samples isolated from E13.5 heart alongside a schematic of the Fkbp1a^flox allele showing the location of diagnostic primers p1, p2 and p3; E, exon. A specific p3-p2 band represents the allele after Cre-loxP-mediated recombination. (B) Morphological and histological analysis of Fkbp1a^flox/-:Tie2-cre and control embryos and hearts at E14.5. Fkbp1a^flox/-:Tie2-cre embryos are edematous (red arrow). The mutant hearts lack a normal ventricular groove (yellow arrows) and demonstrate hypertrabeculation and noncompaction (black arrows). RA, right atrium; LA, left atrium; RV, right ventricle; LV, left ventricle; VSD, ventricular septal defect.