Expression pattern of irf8 and costaining of irf8 with csf1r and mpx. (A-B) WISH indicates irf8 RNA expression in the yolk sac of 18 hpf WT embryos (n = 35/35). (C) WISH shows irf8 RNA expression in the CHT^25,26  of 30 hpf WT embryo (n = 36/38). (D) WISH reveals irf8 RNA expression in the head region of 2 dpf WT embryo (n = 33/39). (A-D) Blue arrows indicate the irf8 signals. (E-F) Double WISH staining of csf1r and irf8 RNA in the CHT of 30 hpf WT embryos (n = 32/35). (E/F) Superimposed image of panels E and F. (E′/F′) Merged view of E/F with DIC image. (G-H) Double staining of mpx-GFP and irf8 RNA in the CHT of 30 hpf Tg (mpx:eGFP) embryos (n = 29/31). (G/H) Superimposed image of panels G and H. (G′/H′) Merged view of panel G/H with DIC image. (E,E/F,E′/F′) Blue arrowheads represent neural crest-derived pigment cells positive for csf1r. (E-G′/H′) Insets are higher magnification (×40) views of the circled region in panels E and G.