Fig. 1

Fig. 1 Phenotype analysis and proviral insertion mapping of zebrafish No. 12615 retrovirus insertional mutant. (A)–(D) Images of the phenotype of No. 12615 homozygous mutant embryos under bright-field. At 24 hpf, the mutant embryo (B) is indistinguishable from the wild-type (A); at 28 hpf, the mutant embryo (D) exhibits less pigmentation (red arrowhead) and slight edema of the pericardial cavity (blue arrowhead) than those of the wild-type (C). (E) eif3ba gene structure. Exogenous retroviral (RV) sequence (red box) inserted into the 2nd exon of eif3ba gene, and resulting in a pre-mature stop codon ‘TGA’. (F, F′) Predicted protein structure of Eif3ba, with part of the second and third exons encoding the important RNA-recognition motif (RRM) domain (orange bar) (F), while in the mutant, the ‘TGA’ stop codon in the proviral sequence leads to the production of a truncated protein which breaks the RRM domain at the second exon (F′). (G)–(I) The mutant embryos are largely rescued by injecting eif3ba mRNA. The injected mutant embryos (n=30/30) (I) show more pigmentation than the control (H) at 2 dpf, and the head morphology is more normal. (J)–(K′) The expression of crestin in the mutant embryos compared with the wild-type at 24 hpf. The expression of crestin dramatically decreased in the mutant embryos, specifically in the cranial region (red triangles) and the branchial primordia (red arrows). WT, wild type; Mut, eif3ba mutant. (A–D, G–I, J, K) Lateral view with anterior to the left and dorsal up; (J′, K′) dorsal view with anterior to the left.