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【目的】鉴定出一种新的亚洲玉米螟Ostrinia furnacalis(Guenée)C型凝集素(C-type lectin),并对其功能进行初步研究。【方法】通过生物信息学分析,从亚洲玉米螟转录组中筛选得到一个可能的C型凝集素基因,命名为CTL6。利用RT-PCR技术分析该基因在亚洲玉米螟不同龄期、不同组织及不同病原物诱导下的表达模式。借助原核及杆状病毒真核表达系统产生重组CTL6蛋白,并利用细菌凝集实验对其功能进行初步研究。【结果】CTL6基因c DNA全长序列为1 034 nt,其中完整开放阅读框为945 nt。推导的CTL6多肽序列包括314个氨基酸残基,N端含有由22个氨基酸残基组成的信号肽。CTL6成熟肽中含有两个串联的糖识别结构域,与烟草天蛾Manduca sexta的IML-2(Immulectin-2)同源性最高。RT-PCR结果显示,CTL6在亚洲玉米螟5龄幼虫期转录水平最高,卵期其次,不同组织中则是在脂肪体中转录水平最高,呈诱导性表达。纯化的CTL6重组蛋白对大肠杆菌Escherichia coli具有一定的凝集作用。【结论】鉴定到的亚洲玉米螟CTL6是一种典型的C型凝集素,重组CTL6蛋白可能参与了亚洲玉米螟对病原菌的凝集作用。
【Objective】 A new type of Ostrinia furnacalis (Guenée) C-type lectin was identified and its function was preliminary studied. 【Method】 By bioinformatics analysis, a possible C-type lectin gene was screened from the transcriptome of the Asian corn borer and named CTL6. The expression pattern of this gene was induced by different tissues and pathogens in different stages of Asian corn borer by RT-PCR. The prokaryotic and baculovirus eukaryotic expression system was used to generate recombinant CTL6 protein, and its function was preliminary studied by bacterial agglutination test. 【Results】 The full length cDNA of CTL6 gene was 1 034 nt, of which the complete open reading frame was 945 nt. The deduced CTL6 polypeptide sequence consists of 314 amino acid residues and the N-terminal contains a signal peptide consisting of 22 amino acid residues. The mature peptide of CTL6 contains two tandem sugar recognition domains, and has the highest homology with IML-2 (Immulectin-2) of Manduca sexta. RT-PCR results showed that CTL6 had the highest transcript level in the 5th instar larvae of the Asian corn borer, and the highest transcript level in adipose tissues in the ovary period. The purified CTL6 recombinant protein has some agglutination on Escherichia coli. 【Conclusion】 The identified CTL6 is a typical C-type lectin. The recombinant CTL6 protein may be involved in the agglutination of the pathogen of Asian corn borer.