Zebrafish have two khdrbs1 genes, khdrbs1a and khdrbs1b. Different from control group (Supplementary Figures 1A–F), both khdrbs1a and khdrbs1b were pan-expressed in the blastoderm and the embryo per se (Figures 5A–E,A′–E′). At 24 hpf, khdrbs1a expression was detected in the brain (Figures 6A–D), eye, spinal cord, lateral line primordium, gonad primordium, pectoral fin, and caudal fin (Figures 5F–I), while khdrbs1b expression was relatively weak in the brain (Figures 6A′–D′), eye, lateral line primordium, and spinal cord (Figures 5F′–I′). By 48 hpf (Figures 5J–M) and 72 hpf (Figures 5N–Q), khdrbs1a expression in the brain (Figures 6E–L) and pectoral fin enhanced, and the signal at the lateral line neuromast was evident. Additional expressions were also observed in the pharyngeal arch, pronephric ducts (Figure 7) and otic vesicle, but the expression signals in the spinal cord and caudal fin apparently faded. Compared to khdrbs1a, khdrbs1b was not expressed in the lateral line by 48 hpf (Figures 5J′–M′); instead, its expression was restricted to the brain (Figures 6E′–H′), eye, pharyngeal arch and pectoral fin, and this expression pattern remained till 72 hpf (Figures 5N′–Q′, 6I′–L′).