Abstract: o explore the role ofkdm4abin fish under low temperature,kdm4ab-/-zebrafish was constructed by CRISPR/Cas9. RT-qPCR showed that the mRNA expression level ofkdm4abinkdm4ab-/-zebrafish was significantly reduced (P<0.0001), while the expression of kdm4c level was compensatively increased (P<0.05). The detection of zebrafish behavior trajectory tracking system showed that the maximum acceleration ofkdm4ab-/-larval zebrafish was significantly decreased at 18 ℃ (P<0.05), compared with that of WT larval zebrafish. At 8 ℃, the LT50 ofkdm4ab-/-zebrafish was significantly lower than that of WT zebrafish (P<0.0001). After low temperature treatment, the expression of γH2A.X inkdm4ab-/-zebrafish increased significantly, and the level of ROS increased, which indicated that the DNA damage was enhanced. The results showed thatkdm4abhad a certain effect on the cold tolerance of zebrafish, which also provided a new idea for the low temperature tolerance mechanism of fish.

Key words: kdm4ab, zebrafish, CRISPR/Cas9, cold