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. 2020 Feb 27;9:e50325. doi: 10.7554/eLife.50325

Figure 2. Dullard deletion in cardiac NCC causes asymmetric and premature OFT septation similar to Fallot’s tetralogy.

(A) Three-dimensional rendering of the Pecam+ endocardium of E12 Pax3Cre; Dullardflox/+ and Pax3Cre; Dullardflox/flox embryos after 3Disco clearing and lightsheet acquisition (n = 3 per genotype). The fine oblique white line marks the Pa width. The OFT levels along its distal-proximal axis analyzed in B are also indicated. (B) Immunolabelling for Pecam (red), GFP (green) and DAPI (blue) on transverse sections along the distal-proximal axis of the OFT in E11.5 embryos with the indicated genotypes (n > 10 embryos collected from more than three liters). Brackets in i and iv highlight the symmetric and asymmetric Ao and Pa poles in control and mutant embryos, respectively. Arrowheads in ii and v point at the unruptured and ruptured endocardium in control and mutant embryos, respectively. (C) Percentage of living Dullard mutant embryos before E12.5 and after E12.5, carrying the indicated Cre driver. (D) Immunolabelling for Pecam, GFP and DAPI staining on sections through the hearts of E14.5 (i,ii,v,vi) and E18.5 (iii,iv) embryos with the indicated genotypes (n = 2 embryos per genotype). Arrowheads in ii and arrow in iv point at a septation defect, the star in vi indicates the lack of Pa. (E) Whole dissected E18.5 hearts coming from embryos with the indicated genotype (n = 2 per genotype). (F) Two cycles of blood flow measured at the level of the abdominal artery of E11.75 control embryos and indication of the parameters analysed. VTI: velocity time integral. Parameters (i-iii) of the blood flow velocity measured in the abdominal artery of E11.75 control (turquoise dots) and Wnt1Cre; Dullardflox/flox embryos (purple squares)(dots and squares: mean of two to five measures obtained on a single embryo, bars: mean ± s.e.m; differences evaluated using a Mann-Whitney test: N.S. non-significant, *: p<0.05, **: p<0.01, ***: p<0.001). i. peak systolic velocity, ii. end-diastolic velocity, iii. mean of three velocity time integrals (n = 10 mutants and n = 32 controls). Ao: aortic artery, Pa: pulmonary artery, PV IC: pulmonary valve intercalated-cushion.

Figure 2.

Figure 2—figure supplement 1. Morphological defects in Dullard mutants become striking from E11.5 onwards.

Figure 2—figure supplement 1.

(A) MF20 (myosin heavy chain) and GFP immunostaining and DAPI staining on transverse sections (i,iii) and coronal sections (ii,iv) in E10.5 embryos with the indicated genotype. (B) Immunolabelling for Pecam (red) and GFP (green) and DAPI (blue) staining on transverse sections along the distal-proximal axis of the OFT in E11.5 embryos with the indicated genotypes (n > 10 embryos collected from more than three liters). (C) Immunolabelling of MF20, Isl1/2, Pecam and GFP, as well as DAPI staining, on transverse sections of E11.5 hearts of embryos with the indicated genotypes. Ao: Aorta; Pa: pulmonary artery; ba: branchial arch; myoc: myocardium; Lv: left ventricle; Rv: right ventricle.