Expression patterns of lgr4 in zebrafish embryos. (A–H) lgr4 expression was examined by whole-mount in situ hybridization at the 5s, 15s, and 18s stages and at 24 hpf. Dorsal views from the anterior (A, C, E, and G) to the posterior (D and F). A vegetal pole view of the tail-bud region (B). A lateral view, anterior to the left (H). Arrow indicates Kupffer’s vesicle; arrowheads indicate the brain ventricular zone; asterisks indicate the weak and ubiquitous expression of lgr4 in the head. bvz, brain ventricular zone; e, eyes; fb, forebrain; kV, Kupffer’s vesicle; mb, midbrain; npb, neural plate border; nt, neural tube; op, optic primordia; ov, otic vesicles.

Expression patterns of lgr4 in zebrafish larvae. (A–K) lgr4 expression was examined by whole-mount in situ hybridization at 36, 48, 72, and 96 hpf. Lateral views, anterior to the left (A, D, F, and I). Dorsal views, anterior to the left (B, C, E, G, and J). A ventral view of (F and G) (H). A magnified view of the eye in (I and J) (K). (L) A transverse section showing the lgr4 expression. The transverse section was cut at the level indicated by a black line in (I). Asterisks indicate the cranial cavity; arrowhead indicates the ciliary marginal zone. bvz, brain ventricular zone; ch, ceratohyals; cmz, ciliary marginal zone; i, intestine; ib, intestinal bulb; L, liver; mc, Meckel’s cartilages; mhb, midbrain–hindbrain boundary; nc, notochord; ov, otic vesicles; p, pancreas; pa, pharyngeal arches; pf, pectoral fin buds; pq, palatoquadrates.

Comparison between the lgr4-expressing domains and the BrdU-incorporating proliferative zones. (A, C, E, G, I, and K) Whole-mount embryos and larvae at the indicated stages hybridized with an antisense lgr4 riboprobe. (B, D, F, H, J, and L) BrdU labeling of developing embryos and larvae at the indicated stages. (A, B, E, F, I, and J) Lateral views; (C, D, G, H, K, and L) dorsal views. For all images, anterior to the left. Many of the lgr4-expressing domains are similar to the BrdU-incorporating proliferative zones from 24 to 72 hpf. aeov, anterior end of otic vesicles; bvz, brain ventricular zone; mhb, midbrain–hindbrain boundary; ov, otic vesicles; pa, pharyngeal arches; peov, posterior end of otic vesicles; pf, pectoral fin buds.

Expression patterns of lgr6 during zebrafish development. (A–K) lgr6 expression was examined by whole-mount in situ hybridization. Lateral views, anterior to the left (A, C, D, E, G, H, and K). A vegetal pole view of the tail-bud region (B). Dorsal views, anterior to the left (F and I). A ventral view of (H and I) (J). an, anterior neuromasts; ALLP, anterior lateral line primordium; ch, ceratohyals; di, diencephalon; kV, Kupffer’s vesicle; mc, Meckel’s cartilages; nc, notochord; ov, otic vesicles; pa, pharyngeal arches; pf, pectoral fin buds; pn, posterior neuromasts; PLLP, posterior lateral line primordium; tr, trabeculae.

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