家蝇防御素基因的cDNA克隆及序列分析  

Cloning and sequence analysis of the full-length cDNA encoding defensin, an antimicrobial peptide from the housefly (Musca domestica)

作　　者：王来城[1] 王金星[1] 王来元[1] 赵小凡[1] 

机构地区：[1]山东大学生命科学学院,济南250100

出　　处：《动物学报》2003年第3期408-413,共6页ACTA ZOOLOGICA SINICA

基　　金：高等学校骨干教师资助计划项目 (GG- 180 - 2 5 0 10 0 0 1 -1995 );博士点专项基金 ( 2 0 0 2 0 42 2 0 5 2 );山东省科技厅计划项目( 0 12 10 0 10 4)资助~~

摘　　要：Defensin is a kind of cationic, inducible antimicrobial peptide found in a large range of living organisms that contributes to host defense by disrupting the cytoplasmic membrane of microorganisms. With their broad antimicrobial spectrum and strong pharmaceutical effects, antimicrobial peptides, including defensins, represent a source of novel antibiotic agents. A novel full-length 430 base pairs cDNA of an insect defensin was cloned using polymerase chain reaction (PCR) from the cDNA library of houseflies (Musca domestica) that had been challenged by E. coli and Staphylococcus aureus. Sequence analysis revealed that the open reading frame of the cDNA encoded a 92-amino acid peptide, which contained an NH 2-terminal signal sequence (1-22) followed by a propeptide and the mature peptide (53-92). The sequence identity with other insect defensin is between 51% and 73%. The mature peptide, with a predicted molecular weight of 4\^0 kDa, and pI of 8\^69, has 1 negative charged amino acid and 4 positice ones. The putative housefly defensin is characterized by 6 invariant cysteine residues forming 3 disulfide bonds, Cys1-Cys4, Cys2-Cys5 and Cys3-Cys6. These results suggest that the novel full-length cDNA of the defensin gene, denominated Mdde, has been successfully cloned from houseflies.Defensin is a kind of cationic, inducible antimicrobial peptide found in a large range of living organisms that contributes to host defense by disrupting the cytoplasmic membrane of microorganisms. With their broad antimicrobial spectrum and strong pharmaceutical effects, antimicrobial peptides, including defensins, represent a source of novel antibiotic agents. A novel full-length 430 base pairs cDNA of an insect defensin was cloned using polymerase chain reaction (PCR) from the cDNA library of houseflies (Musca domestica) that had been challenged by E. coli and Staphylococcus aureus. Sequence analysis revealed that the open reading frame of the cDNA encoded a 92-amino acid peptide, which contained an NH 2-terminal signal sequence (1-22) followed by a propeptide and the mature peptide (53-92). The sequence identity with other insect defensin is between 51% and 73%. The mature peptide, with a predicted molecular weight of 4\^0 kDa, and pI of 8\^69, has 1 negative charged amino acid and 4 positice ones. The putative housefly defensin is characterized by 6 invariant cysteine residues forming 3 disulfide bonds, Cys1-Cys4, Cys2-Cys5 and Cys3-Cys6. These results suggest that the novel full-length cDNA of the defensin gene, denominated Mdde, has been successfully cloned from houseflies.

关 键 词：家蝇 防御素基因 CDNA 克隆 序列分析 昆虫 免疫防御系统 

分 类 号：Q785[生物学—分子生物学]