| Download | - View final version: Dominant negative mutants of Bacillus thuringiensis Cry1Ab toxin function as anti-toxins: demonstration of the role of oligomerization in toxicity (PDF, 679 KiB)
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| DOI | Resolve DOI: https://doi.org/10.1371/journal.pone.0005545 |
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| Author | Search for: Rodríguez-Almazán, Claudia; Search for: Zavala, Luis Enrique; Search for: Muñoz-Garay, Carlos; Search for: Jiménez-Juárez, Nuria; Search for: Pacheco, Sabino; Search for: Masson, Luke1; Search for: Soberón, Mario; Search for: Bravo, Alejandra |
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| Editor | Search for: Yang, Ching-Hong |
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| Affiliation | - National Research Council of Canada. NRC Biotechnology Research Institute
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| Format | Text, Article |
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| Abstract | Background: Bacillus thuringiensis Cry toxins, that are used worldwide in insect control, kill insects by a mechanism that depends on their ability to form oligomeric pores that insert into the insect-midgut cells. These toxins are being used worldwide in transgenic plants or spray to control insect pests in agriculture. However, a major concern has been the possible effects of these insecticidal proteins on non-target organisms mainly in ecosystems adjacent to agricultural fields. Methodology/Principal Findings: We isolated and characterized 11 non-toxic mutants of Cry1Ab toxin affected in different steps of the mechanism of action namely binding to receptors, oligomerization and pore-formation. These mutant toxins were analyzed for their capacity to block wild type toxin activity, presenting a dominant negative phenotype. The dominant negative phenotype was analyzed at two levels, in vivo by toxicity bioassays against susceptible Manduca sexta larvae and in vitro by pore formation activity in black lipid bilayers. We demonstrate that some mutations located in helix α-4 completely block the wild type toxin activity at sub-stoichiometric level confirming a dominant negative phenotype, thereby functioning as potent antitoxins. Conclusions/Significance: This is the first reported case of a Cry toxin dominant inhibitor. These data demonstrate that oligomerization is a fundamental step in Cry toxin action and represent a potential mechanism to protect special ecosystems from the possible effect of Cry toxins on non-target organisms. |
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| Publication date | 2009-05-14 |
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| Publisher | Public Library of Science |
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| In | |
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| Language | English |
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| Peer reviewed | Yes |
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| NPARC number | 23004735 |
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| Export citation | Export as RIS |
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| Report a correction | Report a correction (opens in a new tab) |
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| Record identifier | 1053e3ab-64a5-42e6-9182-1f2cabf3a5a6 |
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| Record created | 2018-12-14 |
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| Record modified | 2020-05-30 |
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