title: Interaction of Bacillus thuringiensis vegetative insecticidal protein with ribosomal S2 protein triggers larvicidal activity in Spodoptera frugiperda.
abstract: Vegetative insecticidal protein (Vip3A) is synthesized as an extracellular insecticidal toxin by certain strains of Bacillus thuringiensis. Vip3A is active against several lepidopteran pests of crops. Polyphagous pest, Spodoptera frugiperda, and its cell line Sf21 are sensitive for lyses to Vip3A. Screening of cDNA library prepared from Sf21 cells through yeast two-hybrid system with Vip3A as bait identified ribosomal protein S2 as a toxicity-mediating interacting partner protein. The Vip3A-ribosomal-S2 protein interaction was validated by in vitro pulldown assays and by RNA interference-induced knockdown experiments. Knockdown of expression of S2 protein in Sf21 cells resulted in reduced toxicity of the Vip3A protein. These observations were further extended to adult fifth-instar larvae of Spodoptera litura. Knockdown of S2 expression by injecting corresponding double-stranded RNA resulted in reduced mortality of larvae to Vip3A toxin. Intracellular visualization of S2 protein and Vip3A through confocal microscopy revealed their interaction and localization in cytoplasm and surface of Sf21 cells.
authors.affiliation: Insect Resistance Group, International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi 110067, India.
authors.forename: Gatikrushna
authors.initials: G
authors.lastname: Singh
authors.forename: Bindiya
authors.initials: B
authors.lastname: Sachdev
authors.forename: Nathilal
authors.initials: N
authors.lastname: Sharma
authors.forename: Rakesh
authors.initials: R
authors.lastname: Seth
authors.forename: Raj K
authors.initials: RK
authors.lastname: Bhatnagar
mesh_terms: D000818:Animals; D001413:Bacillus thuringiensis / Q000502:physiology*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D015152:Blotting, Northern; D002460:Cell Line; D007814:Larva; D018613:Microscopy, Confocal; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012269:Ribosomal Proteins / Q000096:biosynthesis / Q000378:metabolism / Q000502:physiology*; D018411:Spodoptera / Q000187:drug effects / Q000502:physiology*
chemical_list: D001426:Bacterial Proteins; D012269:Ribosomal Proteins; C447139:Vip3A protein, Bacillus thuringiensis; C030004:ribosomal protein S2