The insecticidal toxin Makes caterpillars floppy (Mcf) promotes apoptosis in mammalian cells
The insecticidal toxin Makes caterpillars floppy (Mcf) promotes apoptosis in mammalian cells
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DOI：
10.1046/j.1462-5822.2003.00357.x
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发表时间：
2004-04-01
影响因子：
3.4
通讯作者：
ffrench-Constant, RH
中科院分区：
文献类型：
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作者：
Dowling, AJ;Daborn, PJ;ffrench-Constant, RH
发光杆菌属细菌产生许多毒素来杀死它们的昆虫宿主。其中之一的表达，使毛毛虫松软（Mcf），足以让大肠杆菌坚持和杀死毛毛虫。Mcf引起昆虫中肠上皮脱落和血细胞破坏性起泡，表明它可能引发细胞凋亡。为了研究这一假设，我们在这里研究了E。coli在哺乳动物细胞系COS-7、NIH 3 T3和HeLa细胞上表达Mcf。用Mcf处理的细胞在6 h后显示凋亡的核形态、活性半胱天冬酶-3、DNA梯状化，并且在16 h后存在裂解的PARP。这些作用被细胞凋亡抑制剂zVAD-favorite阻止。用仅表达Mcf的NH 2-末端1280个氨基酸的构建体转染细胞，作为与Myc的融合，也引发细胞破坏。表达的融合蛋白在细胞死亡前被浓缩到高尔基体中。这些结果证实了新的杀虫毒素Mcf诱导细胞凋亡，但精确的细胞内途径仍然不清楚。
Photorhabdus bacteria produce a number of toxins to kill their insect hosts. The expression of one of these, Makes caterpillars floppy (Mcf), is sufficient to allow Escherichia coli to persist within and kill caterpillars. Mcf causes shedding of the insect midgut epithelium and destructive blebbing of haemocytes suggesting it may trigger apoptosis. To investigate this hypothesis, here we examine the effects of E. coli-expressed Mcf on the mammalian cell lines COS-7, NIH 3T3 and HeLa cells. Cells treated with Mcf show apoptotic nuclear morphology, active caspase-3, DNA laddering after 6 h, and the presence of cleaved PARP after 16 h. These effects are prevented by the apoptosis inhibitor zVAD-fmk. Transfection of cells with constructs expressing only the NH2-terminal 1280 amino acids of Mcf, as a fusion with Myc, also triggered cell destruction. The expressed fusion protein was concentrated into the Golgi apparatus before cell death. These results confirm that the novel insecticidal toxin Mcf induces apoptosis but the precise intracellular pathway remains obscure.