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. 2019 Sep 23;146(18):dev177618. doi: 10.1242/dev.177618

Fig. 3.

Fig. 3.

Pax9–/– embryos display aberrant rotation of the outflow tract and abnormal PAA remodelling. Image datasets were acquired by high-resolution episcopic microscopy. (A-D) 3D reconstructions of the PAAs at E11.5 (45-50 s). (A) In Pax9+/+ control embryos (n=5), the outflow tract is septated, the right 6th PAA has thinned and the carotid duct (cd) has begun to involute. (B-D) In Pax9–/– embryos (n=4), the 4th PAAs are absent and the 3rd PAAs are aberrantly connected or detached from the dorsal aorta (da; asterisks). The carotid duct has failed to involute and septation of the outflow tract is delayed. Persisting 1st or 2nd PAAs are observed coursing anteriorly from the abnormal 3rd PAAs (B,D) or from the aortic sac (as; C). (E,F) Looping of the heart tube at E10.5 was not affected in Pax9–/– embryos (n=4). (G-L) Outflow tract rotation from E10.5 to E11.5 (39-49 s). (G-I) In control embryos, the major outflow tract cushions (parietal in green; septal in yellow) rotated in an anti-clockwise direction, resulting in the cushions being aligned side by side. (J-L) In Pax9–/– embryos, the cushions rotated in a clockwise direction, resulting in the parietal cushion being anterior to the septal cushion. at, aortic trunk; pa, pulmonary arteries; pt, pulmonary trunk. Somite (s) counts indicated. Scale bars: 100 μm.