Expression of zebrafish <i>alk</i>.

<p><b>(A)</b> RT-PCR of cDNA at different embryonic stages. <i>gapdh</i> is used as loading control. <b>(B)</b> RT-PCR of cDNA from different adult tissues. <i>beta-actin</i> is used as loading control. <b>(C)</b> Lateral view of whole embryos at 24 hpf with dorsal up and anterior to the left. Insert shows dorsal view of head region. <b>(D–G)</b> Transverse sections of embryos at 24 hpf, at forebrain (D), midbrain (E), rhombomere 2 (r2; F) and r5 (G) levels, corresponding to positions indicated by lines in (C). <b>(H)</b> Lateral view of whole embryo at 48 hpf with dorsal up and anterior to the left. Insert shows dorsal view of head region. <b>(I–K)</b> Transverse sections of embryos at 48 hpf at forebrain (I), midbrain (J), and r5 (K), corresponding to positions indicated by lines in (D). Scale bars: C,H, 200 µm; D–E,I–K, 100 µm.