Institute of Molecular Biosciences, Mahidol University, Salaya, Thailand.
Curr Microbiol. 2012 Oct;65(4):446-54. doi: 10.1007/s00284-012-0178-4. Epub 2012 Jul 6.
Bacillus thuringiensis (Bt) produces insecticidal toxins active against insects. Cry4B, one of the major insecticidal toxins produced by Bt subsp. israelensis, is highly toxic to mosquitoes in the genus Aedes: the major vectors of dengue, yellow fever, and chikungunya. Previous work has shown that Cry4B binds to several mid-gut membrane proteins in Aedes aegypti larvae including prohibitin, a protein recently identified as a receptor that also mediates entry of dengue virus into Aedes cells. This study confirms the interaction between Cry4B and prohibitin by co-immunoprecipitation analysis and demonstrates colocalization of prohibitin and Cry4B by confocal microscopy. While activated Cry4B toxin showed high larvicidal activity, it was not cytotoxic to two Aedes cell lines, allowing determination of its effect on dengue virus infectivity in the absence of Cry4B-induced cell lysis. Pre-exposure of Aedes cells to Cry4B resulted in a significant reduction in the number of infected cells compared to untreated cells.
苏云金芽孢杆菌（Bt）产生对昆虫具有杀虫活性的毒素。Cry4B 是苏云金芽孢杆菌亚种 israelensis 产生的主要杀虫毒素之一，对伊蚊属的蚊子具有高度毒性：这些蚊子是登革热、黄热病和基孔肯雅热的主要传播媒介。先前的工作表明，Cry4B 与埃及伊蚊幼虫中的几种中肠膜蛋白结合，包括抑制素，该蛋白最近被鉴定为一种受体，也介导登革病毒进入 Aedes 细胞。本研究通过共免疫沉淀分析证实了 Cry4B 与抑制素之间的相互作用，并通过共聚焦显微镜证明了抑制素和 Cry4B 的共定位。虽然激活的 Cry4B 毒素显示出很高的杀幼虫活性，但对两种埃及伊蚊细胞系没有细胞毒性，这允许在没有 Cry4B 诱导的细胞裂解的情况下确定其对登革热病毒感染力的影响。与未处理的细胞相比，Cry4B 预先暴露于 Aedes 细胞可导致感染细胞的数量显著减少。
