Methyltransferase-like 8 (mettl8) is a protein-coding gene that may demonstrate nucleic acid or protein methyltransferase activity. Although several members of the METTL protein family have been reported, the expression and function of this family are still poorly understood, especially in fish. Medaka (Oryzias latipes) is an important model organism with relatively complete genome information, and more and more genetic toolkits are available for this fish. The popularity of medaka among developmental biologists has led to important insights into vertebrate development. Here, we report the DNA sequence and expression of mettl8 in medaka. The full-length cDNA of medaka mettl8 is 1266 bp, and its predicted open reading frame codes for a protein with 393 amino acids. The predicted molecular mass was 45.8 kDa, and the theoretical isoelectric point was 8.61. It had a conserved methyltransferase domain in METTL8 proteins. Homology analysis revealed that medaka METTL8 clustered in close proximity with the METTL8 of Austrofundulus limnaeus and Nothobranchius furzeri within the Cyprinodontiformes branch, and the protein structure of METTL8 was highly conserved. During embryogenesis, the mettl8 transcript was highly expressed in early stages, while it persisted at a detectable level until the larvae stage. In adult fish, the RT-PCR result indicated that mettl8 mRNA was expressed in the brain, eye, skin, liver, intestine, ovary, and testis. Slice in situ hybridization analysis showed that mettl8 was highly expressed in the eye, intestine, ovary, and testis. The expression and distribution of mettl8 during embryogenesis were also demonstrated by whole mount in situ hybridization. The results indicated that the mettl8 is expressed significantly in the eye, somite, and otic vesicles. Immunofluorescence and Western blot analyses showed that METTL8 protein was present in both the nuclei and cytoplasm. This study lays a foundation for further research on the function of fish mettl8.

甲基转移酶样8（mettl8）是一种蛋白质编码基因，可显示核酸或蛋白质甲基转移酶活性。尽管已报道了METTL蛋白家族的几个成员，但对该家族的表达和功能仍知之甚少，尤其是在鱼类中。Medaka（Oryzias latipes）是一种重要的模式生物，具有相对完整的基因组信息，并且有越来越多的遗传工具可用于该鱼。medaka在发育生物学家中的流行引起了对脊椎动物发育的重要见解。在这里，我们报告了在medaka中mettl8的DNA序列和表达。medaka mettl8的全长cDNA长度为1266 bp，其预测的开放阅读框编码具有393个氨基酸的蛋白质。预测的分子量为45.8 kDa，理论等电点为8.61。它在METTL8蛋白中具有保守的甲基转移酶结构域。同源性分析表明，青akaMEDTL8与the形纲分支内的澳尾fund和短支线夜蛾的METL8紧密聚集，并且METTL8的蛋白质结构高度保守。在胚胎发生过程中，mettl8转录物在早期高度表达，而在幼虫阶段一直以可检测的水平持续存在。在成年鱼中，RT-PCR结果表明mettl8mRNA在脑，眼，皮肤，肝，肠，卵巢和睾丸中表达。切片原位杂交分析表明，mettl8在眼，肠，卵巢和睾丸中高表达。mettl8在胚胎发生过程中的表达和分布也通过完整的原位杂交证明。结果表明，mettl8在眼，体节和耳小泡中显着表达。免疫荧光和蛋白质印迹分析表明，METTL8蛋白存在于细胞核和细胞质中。该研究为鱼类的功能的进一步研究奠定了基础mettl8。