title: Vip3Aa induces apoptosis in cultured Spodoptera frugiperda (Sf9) cells.
abstract: The vegetative insecticidal proteins (Vip) secreted by many Bacillus thuringiensis strains during their vegetative growth stage are regarded as second generation insecticidal proteins, as they share no sequence or structural homology with known crystal insecticidal proteins (Cry) and have a broad insecticidal spectrum. Compared with insecticidal crystal proteins (ICPs), the insecticidal mechanisms of Vips have been little studied. Here we investigated the mechanism responsible for Vip3Aa toxicity in cultured insect cells. Using, flow cytometry analyzes, TUNEL staining and DNA fragmentation assays, we show that Vip3Aa can induce apoptosis in Spodoptera frugiperda (Sf9) cells and cause cells to arrest at the G2/M phase. We also show that Vip3Aa can disrupt mitochondrial membrane potential (ΔΨm), leading to the activation of Sf-caspase-1, suggesting that a mitochondrial mediated and caspase dependent pathway may be involved in Vip3Aa-induced apoptosis in Sf9 cells.
authors.affiliation: Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China.
authors.forename: Kun
authors.initials: K
authors.lastname: Jiang
authors.affiliation: Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China.
authors.forename: Si-Qi
authors.initials: SQ
authors.lastname: Mei
authors.affiliation: Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China.
authors.forename: Ting-Ting
authors.initials: TT
authors.lastname: Wang
authors.affiliation: Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China.
authors.forename: Jin-Hua
authors.initials: JH
authors.lastname: Pan
authors.affiliation: Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China; Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Tianjin 300071, China; Tianjin Key Laboratory of Microbial Functional Genomics, Tianjin 300071, China.
authors.forename: Yue-Hua
authors.initials: YH
authors.lastname: Chen
authors.affiliation: Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China; Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Tianjin 300071, China; Tianjin Key Laboratory of Microbial Functional Genomics, Tianjin 300071, China. Electronic address: caijun@nankai.edu.cn.
authors.forename: Jun
authors.initials: J
authors.lastname: Cai
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D001426:Bacterial Proteins / Q000633:toxicity*; D020170:Caspase 1 / Q000378:metabolism; D002455:Cell Division / Q000187:drug effects; D004789:Enzyme Activation; D016195:G2 Phase / Q000187:drug effects; D020287:In Situ Nick-End Labeling; D007306:Insecticides / Q000633:toxicity*; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D061987:Sf9 Cells; D018411:Spodoptera
chemical_list: D001426:Bacterial Proteins; D007306:Insecticides; C447139:Vip3A protein, Bacillus thuringiensis; D020170:Caspase 1
keywords: Apoptosis; Bacillus thuringiensis; Insecticidal mechanism; Spodoptera frugiperda (Sf9) cell line; Vip3Aa