Phenotypic grades of nlz morphant fish 24 hpf. nlz1 MO (A–C) or nlz2 MO (D–F) splice site MO injected fish were scored as having a grade 1 (A and D), grade 2 (B and E), or grade 3 (C and F) optic fissure defect. At 24 hpf, the margins of the optic fissure are apposed in normal eyes (G) and closure is just beginning. Bars delineate edges of optic fissure. (Scale bar, 50 μm.) The results of the phenotype profiling are summarized in the bar graph (J) where lower grade closure defects are observed at low doses of either nlz1 or nlz2 MO, yet an effect which is at least additive is seen when these doses are combined. A higher dose of either morpholino produces strong optic fissure defects in morphant fish, which is partially rescued by coinjection of respective wild-type mRNA. Expression of nlz1 (H) and nlz2 (I) in wild-type zebrafish embryos at 24 hpf shows expression at the optic fissure (arrowheads).
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