title: Mode of action of mosquitocidal Bacillus thuringiensis toxins.
abstract: Cry toxins from Bacillus thuringiensis (Bt) are used for insect control. Their primary action is to lyse midgut epithelial cells. In lepidopteran insects, Cry1A monomeric toxins interact with a first receptor and this interaction triggers toxin oligomerization. The oligomeric structure interacts then with a second GPI-anchored receptor that induces insertion into membrane microdomains and larvae death. In the case of mosquitocidal Bt strains, two different toxins participate, Cry and Cyt. These toxins have a synergistic effect and Cyt1Aa overcomes Cry toxin-resistance. We will summarize recent findings on the identification of Cry receptors in mosquitoes and the mechanism of synergism: Cyt1Aa synergizes or suppresses resistance to Cry toxins by functioning as a Cry membrane-bound receptor.
authors.affiliation: Departamento de Microbiologia Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apdo. postal 510-3, Cuernavaca 62250, Morelos, Mexico.
authors.forename: Mario
authors.initials: M
authors.lastname: Soberón
authors.forename: Luisa E
authors.initials: LE
authors.lastname: Fernández
authors.forename: Claudia
authors.initials: C
authors.lastname: Pérez
authors.forename: Sarjeet S
authors.initials: SS
authors.lastname: Gill
authors.forename: Alejandra
authors.initials: A
authors.lastname: Bravo
mesh_terms: D000818:Animals; D001413:Bacillus thuringiensis / Q000737:chemistry*; D001427:Bacterial Toxins / Q000737:chemistry* / Q000633:toxicity*; D009033:Culicidae / Q000187:drug effects; D007814:Larva / Q000187:drug effects; D007915:Lepidoptera / Q000187:drug effects; D008954:Models, Biological; D008958:Models, Molecular
chemical_list: D001427:Bacterial Toxins