Autonomous and non-cell autonomous role of cilia in structural birth defects in mice
Fig 3
Ift140null1/null1 embryos display major anatomical defects at E9.5 and cardiac/great vessel patterning defects at E14.5.
(A–I) 3D reconstructions of E9.5 Ift140+/+ control and littermate homozygous Ift140null1/null1 embryos analyzed by episcopic confocal microscopy. In A-B note the hypertrophy of the first branchial arch (1), and hypotrophy of the other branchial arches (2–4). In C-F note neural tube abnormalities characterized by the head fold failing to close in Ift140null1/null1 embryos (E-F). In G-I note the randomization of heart tube looping characterized by normal D-looped (G), reversed L-looped (H), and midline A-looped (I) heart tubes. (J–L) Sagittal section reconstructions of Ift140null1/null1 embryos further highlight the abnormal midline A-looped heart tube phenotype (L) observed in some Ift140null1/null1 embryos compared to embryos with D-looped (J) or L-looped (K) heart tubes. (M) Quantification of the Ift140null1/null1 heart looping defects reveals the randomization of looping phenotypes compared with wild-type embryos (n = 22). (N) Measurement of the OFT length in E10.5 embryos showed significant lengthening of the OFT in the Ift14O KO embryos. Data is mean ± SD. * p = 0.0007 assessed by unpaired Student t test. (O–V) Numerous cardiac and great vessel defects were seen in E14.5 Ift140null1/null1 embryos including: small ventricles (O vs. S), AVSDs with mutant embryos displaying a complete absence of normal atrial septum (arrow P vs. T), PTA characterized by a single OFT due to OFT failing to septate into separate aorta and pulmonary vessels (Q vs. U), and TEF characterized by a single unseptated tracheoesophageal tube (R vs. V). (W) Great vessel patterning was also perturbed in Ift140null1/null1 embryos (n = 7). Besides PTA, mutants showed a combination of singular or double left and right descending aortas. *: somites; 1, 2, 3, 4: Branchial arches; A: aorta; AVSD: atrioventricular septal defect; dA: descending aorta; f: forebrain; fl: forelimb; h: hindbrain; ht: heart tube; if: inflow tract; LA: left atrium; LCA: left carotid artery; LSA: left subclavian artery; LV: left ventricle; lv: liver; m: midbrain; o: esophagus; of: outflow tract; P: pulmonary trunk; PTA: persistent truncus arteriosus; RA: right atrium; RCA: right carotid artery; RV: right ventricle; t: trachea; tn: tongue; TEF: tracheoesophageal fistula; arrowhead: ventricular septal defect; arrow: atrial septum. Scales bars: A, B, J, K, L, N–U = 0.5 mm, C–I = 0.25 mm. The data underlying this figure can be found in supplemental file S1 Data.