日本血吸虫凋亡相关基因SjBAK的初步研究

A PRELIMINARY STUDY ON APOPTOSIS ASSOCIATE GENES SJBAK OF SCHISTOSOMA JAPONICUM

利用PCR技术扩增日本吸血虫凋亡相关基因BAK(Bcl-2 homologous antagonist/killer),并构建重组质粒。应用Realtime PCR技术分析在日本血吸虫非易感宿主大鼠和易感宿主小鼠来源、不同发育阶段虫体中BAK基因的表达状况。结果显示,克隆获得日本血吸虫(Schistosoma japonicum,Sj)BAK编码基因Sj BAK,其ORF含2142bp,编码713个氨基酸,理论分子量为79.3 k Da,理论等电点为4.9。结构域分析表明该基因编码蛋白具有至少3个BH结构域,属于Bcl家族成员。Real-time PCR结果显示该基因在大、小鼠来源4个不同发育阶段虫体均有表达,其中大鼠来源虫体Sj BAK的表达水平都高于小鼠来源虫体,在感染后32 d和42 d表达差异具有显著统计学意义(P<0.05)。由此可推测日本血吸虫凋亡相关基因Sj BAK在血吸虫生长发育中可能发挥重要的作用。

The objectives of the present study were to clone the apoptosis related gene of Schistosoma japonicum SjBAK（Bcl-2 homologous antagonist/killer）, analyze its expression in schistosome worms and possible role in the development of schistosome. The full-length sequence of SjBAK was cloned in PCR and the recombinant plasmid containing Sjq3AK was constructed. The expression of SjBAK in S. japonicum at different development stages from non-susceptible host rats and susceptible host mice were analyzed using Real-time PCR. The ORF of the Sjq3AK gene contained 2142 bp encoding 713 amino acids with the theoretical molecular weight of 79.3 kDa and theoretical isoelectric point at 4.9. Analysis also revealed that the molecule possessed at least three BH domains and belonged to the member of Bcl family. Real-time PCR analysis showed that the gene expressed in all worms at four development stages and the expression level in worms from rats was higher than those from mice. Significant difference in Sjq3AK expression was observed in worms from two different hosts at 32 d and 42 d post-infection（P〈0.05）. In conclusion, the apoptosis-related gene SjBAK of Sjaponicum may play an important role in the development of Schistosome.