目的克隆弓形虫表面抗原SAG3基因,对其结构和功能进行生物信息学分析,为进一步研究奠定基础。方法提取虫体总RNA,RT-PCR扩增SAG3基因并用生物信息学方法对SAG3蛋白的理化性质、结构和功能进行预测。结果扩增出的基因片段约1158bp,与预期相符。预测SAG3蛋白分子质量单位约41.7732ku,PI为6.75,为两亲性蛋白,有2个保守结构域和功能域。结论成功克隆出SAG3基因,为深入研究该基因结构和功能奠定了基础。 Objective To clone Toxoplasma gondii surface antigen (SAG3) gene and analyze its structure and function by bioinformatics, which lays the foundation for further research. Methods Total RNA was extracted from worms. The SAG3 gene was amplified by RT-PCR and the physical and chemical properties, structure and function of SAG3 protein were predicted by bioinformatics methods. Results The amplified gene fragment was about 1158bp, which was in agreement with the expectation. The molecular weight of SAG3 protein was predicted to be 41.7732ku, with a PI of 6.75, an amphipathic protein with two conserved domains and functional domains. Conclusion The successful cloning of SAG3 gene laid the foundation for further study on the structure and function of this gene.