Production of a tributyltin-binding protein 2 knockout mutant strain of Japanese medaka, Oryzias latipes

Tributyltin-binding proteins (TBT-bps), members of the lipocalin family, bind TBT in fish blood and are presumed to contribute to detoxification of TBT. Recent studies have shown that many fish species have TBT-bp genes, and that these genes are induced by stresses such as exposure to chemicals or fish pathogenic bacteria. However, the function of TBT-bps, and the mechanisms of their induction and detoxification activity are still unclear. Here, towards elucidating the functions of TBT-bp2, we produced a TBT-bp2 knockout (TBT-bp2−/−) strain of Japanese medaka, Oryzias latipes, by using the CRISPR/Cas9 system. Gene expression of the mutated TBT-bp2 was reduced, and the cDNA sequencing and predicted protein structure suggested possible loss of function. However, the fish could be grown under normal conditions. Exposure of the TBT-bp2−/− strain of medaka to various stresses in future experiments is expected to contribute to our understanding of this novel detoxification system in aquatic organisms. •TBT-bp2 KO medaka, Oryzias latipes, was produced using the CRISPR/Cas9 system.•Gene analyses of the TBT-bp2 KO suggested possible loss of function.•The KO medaka could be reared in normal conditions.•This strain could be a useful model fish for analyzing the role of TBT-bp2.