目的　扩增SjCL2基因 ,构建巴氏毕赤酵母表达载体 pPICZαB -SjCL2 ,为进一步研究其蛋白酶的功能奠定基础。方法　运用RT -PCR技术 ,从日本血吸虫 (中国大陆株 )成虫总RNA中扩增获得SjCL2基因 ;将其定向克隆至巴氏毕赤酵母表达载体pPICZαB质粒 ;经KpnⅠ、XbaⅠ双酶切分析和PCR鉴定筛选出阳性克隆 ,测序分析SjCL2基因并确定其读码框的正确插入。结果　利用RT -PCR技术从日本血吸虫成虫总RNA中扩增到约 1Kb大小的SjCL2基因 ,通过双酶切分析、PCR鉴定以及DNA序列分析确定SjCL2基因被克隆到巴氏毕赤酵母表达载体 pPICZαB中。 结论　成功构建了含有SjCL2基因编码区序列的巴氏毕赤酵母表达载体 pPICZαB -SjCL2质粒 Objective To amplify SjCL2 gene and construct Pichia pastoris expression vector pPICZαB-SjCL2, which lays the foundation for further study of its protease function. Methods SjCL2 gene was amplified from the total RNA of adult Schistosoma japonicum (Chinese strain) by RT-PCR and cloned into the expression vector pPICZαB of Pichia pastoris. The recombinant plasmid was digested with KpnⅠ, XbaⅠand analyzed by PCR Positive clones were identified and sequenced. The SjCL2 gene was sequenced and the correct insertion of its reading frame was confirmed. Results The SjCL2 gene was amplified from total RNA of Schistosoma japonicum by RT-PCR to about 1 Kb. The SjCL2 gene was cloned into pichia pastoris expression vector pPICZαB by double enzyme digestion analysis, PCR identification and DNA sequence analysis . Conclusion The P. pastoris expression vector pPICZαB-SjCL2 containing the coding region of SjCL2 gene was successfully constructed