Vizioli J, Bulet P, Hoffmann J A, Kafatos F C, Müller H M, Dimopoulos G
Institut de Biologie Moléculaire et Cellulaire, 15 Rue René Descartes, 67084 Strasbourg Cedex, France.
Proc Natl Acad Sci U S A. 2001 Oct 23;98(22):12630-5. doi: 10.1073/pnas.221466798. Epub 2001 Oct 16.
A novel mosquito antimicrobial peptide, gambicin, and the corresponding gene were isolated in parallel through differential display-PCR, an expressed sequence tag (EST) project, and characterization of an antimicrobial activity in a mosquito cell line by reverse-phase chromatography. The 616-bp gambicin ORF encodes an 81-residue protein that is processed and secreted as a 61-aa mature peptide containing eight cysteines engaged in four disulfide bridges. Gambicin lacks sequence homology with other known proteins. Like other Anopheles gambiae antimicrobial peptide genes, gambicin is induced by natural or experimental infection in the midgut, fatbody, and hemocyte-like cell lines. Within the midgut, gambicin is predominantly expressed in the anterior part. Both local and systemic gambicin expression is induced during early and late stages of natural malaria infection. In vitro experiments showed that the 6.8-kDa mature peptide can kill both Gram-positive and Gram-negative bacteria, has a morphogenic effect on a filamentous fungus, and is marginally lethal to Plasmodium berghei ookinetes. An oxidized form of gambicin isolated from the cell line medium was more active against bacteria than the nonoxidized form from the same medium.
通过差异显示PCR、表达序列标签（EST）项目以及利用反相色谱法对蚊细胞系中的抗菌活性进行表征，并行分离出了一种新型蚊子抗菌肽——冈比亚菌素（gambicin）及其相应基因。616bp的冈比亚菌素开放阅读框（ORF）编码一个81个氨基酸残基的蛋白质，该蛋白质经加工后分泌为一个61个氨基酸的成熟肽，含有八个形成四个二硫键的半胱氨酸。冈比亚菌素与其他已知蛋白质缺乏序列同源性。与冈比亚按蚊的其他抗菌肽基因一样，冈比亚菌素在中肠、脂肪体和类血细胞系中受到自然感染或实验感染的诱导。在中肠内，冈比亚菌素主要在前部表达。在自然疟疾感染的早期和晚期，冈比亚菌素的局部和全身表达均被诱导。体外实验表明，这种6.8kDa的成熟肽既能杀死革兰氏阳性菌，也能杀死革兰氏阴性菌，对丝状真菌有形态发生作用，对伯氏疟原虫动合子有轻微致死作用。从细胞系培养基中分离出的氧化形式的冈比亚菌素比同一培养基中的非氧化形式对细菌更具活性。
