Fish coloration change from disrupting different functional regions in tyrosinase (TYR) gene by gene editing technology

Abstract:

In order to detect the effect of editing different functional regions of genes on fish coloration, fertilized eggs of AB strain of homozygous zebrafish (Danio rerio) were microinjected by CRISPR/Cas9 technology, Tyr gene were disrupted in the exon 2 and non-poly (A) addition signal of 3'-UTR, and mutants with disruption of different functional regions were obtained. The results showed that:the relative expression level of Tyr gene was detected in the examined stages of fertilized egg to 15 dph larvae in wild-type zebrafish, and the relative expression level increased to the highest level at melanin formation of eyes; the melanocytes were not observed in mutant embryo and larvae with disrupting the CDSregion of Tyr gene, displaying complete albino, then, the melanocytes were observed in adult fishes with broken melanocyte stripes. The mutants with disrupting non-poly (A) addition signal of 3'-UTR region of Tyr gene showed the same melanocyte stripes with wild-type zebrafish, indicating normal melanin synthesis in them. It was indicated that significantly phenotypic change would occur by disrupting CDS region of gene, while no obvious phenotypic change was detected by disrupting non-poly (A) addition signal of 3'-UTR region of gene.