Abstract: To explore the biological function of thehdac8gene in fish, zebrafish (Danio rerio) was used as a model organism, using CRISPR/Cas9 gene editing technology, the Cas9 target site was designed for the third exon of thehdac8gene, and gRNA was prepared. The gRNA and Cas9 protein were co-microinjected into zebrafish embryos at one-cell stage. After T7E1 endonuclease digestion, sequencing and sequence alignment, it was confirmed that thehdac8gene was successfully knocked out, and F2homozygous mutant zebrafish with a deletion of 41 base pairs in thehdac8gene were obtained. RT-qPCR showed that compared with that of wild-type zebrafish, the expression ofhdac8mRNA was significantly reduced (P<0.0001), while the expression ofhdac1mRNA was compensatively increased (P<0.05), no significant change was detected withhdac3mRNA expression. Western Blot results showed no significant change of H3K27ac, H3K9me3, H3K4me3 and H3K4me1 levels inhdac8-/- zebrafish and muscle tissue. Behavioral tests of wild-type andhdac8-/- zebrafish larvae using the Danio Vision trajectory tracking system were performed, compared with that of wild-type zebrafish larvae, the maximum acceleration ofhdac8-/- zebrafish larvae showed no significant difference, but the total distance, mean velocity, and mobility were all significantly reduced (P<0.000 1), those indicated that knocking out thehdac8gene affected the locomotion capacity of zebrafish larvae.

Key words: HDAC8, zebrafish, CRISPR/Cas9, locomotion capacity