CRISPR/Cas9‐based genome editing allows for the generation of a Tollip‐deficient zebrafish line. (A) Schemes of the zebrafish tollip transcript variants 1 and 2 (v1 and v2), based on the Ensembl database, showing exons (E), translated sequences (gray), and UTR regions (white). (B) Schematic illustration of the structure of Tollip protein isoforms with the C2 and CUE domains indicated. (C) Partial DNA sequence of the target site within exon 2 of the tollip gene in wild‐type tollip+/+ fish (left) and homozygous tollip −/− knockout fish (right). Deletion of eight nucleotides observed in the mutant line is shadowed in dark gray. There is an additional nucleotide change flanking the deletion (double peak marked R in the chromatogram, corresponding to A or G, with a predicted amino acid change D to G in the truncated protein product), indicating mosaicism of the generated line. (D) Schematic illustration of the predicted structure of Tollip protein isoforms synthesized from the mutated tollip gene. (E) Western blot of the 5 dpf protein lysates from the wild‐type (tollip +/+) line and tollip −/− siblings. Top panel shows Tollip (~ 35 kDa) and a bottom panel shows α‐tubulin (~ 55 kDa) signal. (F) qPCR analysis of the expression of tollip transcripts during early zebrafish development (1–5 dpf). Bars represent the means ± SEM from 3–4 independent experiments (encompassing a pool of 10 larvae/condition). Mann–Whitney U test, *P < 0.05, ****P < 0.0001.
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