Fig. 3

Tbx1 Is Required for Specification of the nkx2.5⁺ Pharyngeal Lineage in the ALPM of Zebrafish Embryos

(A–H) Bright-field images of 2 somite stage (ss) (A, n = 30; E, n = 10), 6 ss (B, n = 60; F, n = 20), 10 ss (C, n = 30; G, n = 11), and 14 ss (D, n = 10; H, n = 10) control (CTRL) (A–D) and tbx1 mutant (E–H) embryos processed by in situ hybridization with an nkx2.5 riboprobe. Dorsal views, anterior up.

(I and J) Bright-field z-stacks of 6 ss CTRL (I; n = 42) and tbx1 mutant (J; n = 13) embryos processed by in situ hybridization with a hand2 riboprobe. Dorsal views, anterior up.

(K–N) Confocal z-stacks of CTRL (K and L) and tbx1 mutant (M and N) Tg(nkx2.5:Kaede) embryos imaged immediately following photoconversion at the 16 ss (K and M) and again at 32 hr post-fertilization (L and N). Four of four CTRL embryos contained photoconverted Kaede protein (Kaede^PC, pseudocolored yellow) in the heart and pharyngeal clusters at 32 hpf. Four of four mutant embryos contained Kaede^PC exclusively in the heart. Dorsal views, anterior up.

In (A)–(K), little to no variation was observed between animals in each experimental group.

Scale bars, 25 μm.