Characterization of the ndrg4 mutant.

(A) Schematic representation of the ndrg4 genomic locus. The extended region on the exon 2 represents the sequence targeted by the CRISPR/Cas9 system. Red: sgRNA binding site. Blue: PAM sequence. ndrg4⁺ corresponds to the wild-type allele; ndrg4 *³¹ and ndrg4 *³⁴ are the loss-of-function alleles used in this study. (B) Schematic of ndrg4 protein product. In ndrg4 *³¹ and ndrg4 *³⁴ mutant fish, the deletions result in a frameshift generating a premature STOP codon at the level of the amino acids 31 and 34 (of 352) in the ndr family domain. Lateral views of a control (C) and a ndrg4 mutant (D) embryos at 72 hpf. The arrows point to the heart, note the pronounced heart edema (white asterisk) observed in the ndrg4 mutant. Lateral view of ndrg4 mRNA expression in a control (E) and a ndrg4-/- embryo (F) at 48hpf. Note the absence of ndrg4 expression in the mutant. Scale bar = 200 μm.