美洲大蠊i型溶菌酶基因的克隆及其功能预测

Molecular Cloing And Function Predicting of i-type Lysozyme Gene From Periplaneta Americana

溶菌酶是昆虫先天性免疫系统的重要组成成分。以冈比亚按蚊i型溶菌酶氨基酸序列为种子序列,在美洲大蠊EST库中查找相似序列。通过RT-PCR和RACE PCR技术,克隆获得美洲大蠊i型溶菌酶基因。生物信息学分析表明,所克隆的溶菌酶基因片段长度为525bp,包括5'非编码区12bp,3'非编码区18bp和完整的开放阅读框495bp,其编码164个氨基酸,包括溶菌酶成熟肽137个氨基酸和27个信号肽氨基酸。经同源比对,它与黑腹果蝇和冈比亚按蚊的i型溶菌酶具有同源性,并且具备了异构肽活性的功能位点H,但缺失了抑菌活性的功能位点E/D/S,这为其功能和分子进化研究提供了重要的基础。

Lysozyme is an important component of insects innate immune system.I-type lysozyme of Anopheles gambiae was used as a probe to search for similar genes in EST library of periplaneta americana.The lysozyme cDNA of Periplaneta Americana was cloned by RT-PCR and RACE PCR methods.Bioinformatic analysis showed that the length of lysozyme fragment was 525bp with 12bp 5＇UTR,18bp 3＇UTR and 495bp ORF.The ORF encoded 164amino acids（aa） including a signal peptide of 27aa and a mature peptide of 137aa.Alignment showed that sequence had identity with the i-type lysozymes of Drosophila melanogaster and Anopheles gambiae.Isopeptidase activity residues（H） was conserved in i-type lysozyme of Periplaneta Americana,but antimicrobial activity residues（E / D / S） missed from it.The result of bioinformatic analysis for i-type lysozyme of periplaneta americana proved important basis for its futher researchs.