We then examined the expression patterns of zebrafish khdrbs2 and khdrbs3 expression. At the early developmental stages, both khdrbs2 and khdrbs3, like khdrbs1, were pan-expressed in the blastoderm and the embryo per se (Figures 8A–E,A′–E′ and Supplementary Figures 1G–L). However, khdrbs2 and khdrbs3 genes both later generated more specific expression patches in the brain, forming a sharp contrast to that of khdrbs1. By 24 hpf (Figures 8F,I,L, 9A–D), khdrbs2 was expressed in the telencephalon, epiphysis, hypothalamus, hind rhombomeres, and spinal cord. Signals in these regions gradually expanded in the midbrain and hindbrain with larva development. At 48 hpf (Figures 8G,J,M, 9E–H) and 72 hpf (Figures 8H,K,N, 9I–L), expression of khdrbs2 was primarily restricted to the tegmentum and tectum, respectively, and expression in the spinal cord disappeared. More interestingly, khdrbs3 signal was observed in the telencephalon, diencephalon, midbrain, and hindbrain at 24 hpf (Figures 8F′,I′,L′, 9A′–D′), and then became localized intensely in the telencephalon, hypothalamus, tegmentum, and hind rhombomeres (Figures 8G′,J′,M′, 9E′–H′). By 72 hpf (Figures 8H′,K′,N′, 9I′–L′), khdrbs3 expression spread out around the midbrain and hindbrain, with additional signals emerging in the retina and tectum.