FOXA transcriptional factor modulates insect susceptibility to Bacillus thuringiensis Cry1Ac toxin by regulating the expression of toxin-receptor ABCC2 and ABCC3 genes

The mechanism of action and receptor binding of a dual-specificity Bacillus thuringiensis var. aizawai ICl delta-endotoxin was studied using insect cell culture. The native protoxin was labelled with 125I, proteolytically activated and the affinity of the resulting preparations for insect cell-membrane proteins was studied by blotting. The active preparations obtained by various treatments had characteristic specificity associated with unique polypeptides, and showed affinity for different membrane proteins. The lepidopteran-specific preparation (trypsin-treated protoxin containing 58 and 55 kDa polypeptides) bound to two membrane proteins in the lepidopteran cells but none in the dipteran cells. The dipteran-specific preparation (protoxin treated sequentially with trypsin and Aedes aegypti gut proteases, containing a 53 kDa polypeptide) bound to a 90 kDa membrane protein in the dipteran (A. aegypti) cells but bound to none in the lepidopteran cells or Drosophila melanogaster cells. The toxicity of trypsin-activated delta-endotoxin was completely inhibited by preincubation with D-glucose, suggesting a role for this carbohydrate in toxin-receptor interaction. The toxicity was also decreased by osmotic protectants to an extent proportional to their viscometric radius. These results support a proposal that initial interaction of toxin with a unique receptor determines the specificity of the toxin, following which cell death occurs by a mechanism of colloid osmotic lysis.

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Genome-wide analysis of V-ATPase genes in Plutella xylostella (L.) and the potential role of PxVHA-G1 in resistance to Bacillus thuringiensis Cry1Ac toxin

International Journal of Biological Macromolecules ◽

10.1016/j.ijbiomac.2021.11.169 ◽

2021 ◽

Author(s):

Chao Xie ◽

Lei Xiong ◽

Min Ye ◽

Lingling Shen ◽

Jingge Li ◽

...

Keyword(s):

Bacillus Thuringiensis ◽

Plutella Xylostella ◽

Potential Role ◽

Genome Wide Analysis ◽

Cry1ac Toxin ◽

Genome Wide

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Study of the allergenic potential of Bacillus thuringiensis Cry1Ac toxin following intra-gastric administration in a murine model of food-allergy

International Immunopharmacology ◽

10.1016/j.intimp.2018.05.029 ◽

2018 ◽

Vol 61 ◽

pp. 185-196 ◽

Cited By ~ 4

Author(s):

Karla I. Santos-Vigil ◽

Damaris Ilhuicatzi-Alvarado ◽

Ana L. García-Hernández ◽

Juan S. Herrera-García ◽

Leticia Moreno-Fierros

Keyword(s):

Food Allergy ◽

Bacillus Thuringiensis ◽

Murine Model ◽

Cry1ac Toxin ◽

Allergenic Potential

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CRISPR/Cas9-mediated knockout of both the PxABCC2 and PxABCC3 genes confers high-level resistance to Bacillus thuringiensis Cry1Ac toxin in the diamondback moth, Plutella xylostella (L.)

Insect Biochemistry and Molecular Biology ◽

10.1016/j.ibmb.2019.01.009 ◽

2019 ◽

Vol 107 ◽

pp. 31-38 ◽

Cited By ~ 24

Author(s):

Zhaojiang Guo ◽

Dan Sun ◽

Shi Kang ◽

Junlei Zhou ◽

Lijun Gong ◽

...

Keyword(s):

Bacillus Thuringiensis ◽

Plutella Xylostella ◽

Diamondback Moth ◽

Cry1ac Toxin ◽

High Level ◽

Level Resistance

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The Cadherin Cry1Ac Binding-Region is Necessary for the Cooperative Effect with ABCC2 Transporter Enhancing Insecticidal Activity of Bacillus thuringiensis Cry1Ac Toxin

Toxins ◽

10.3390/toxins11090538 ◽

2019 ◽

Vol 11 (9) ◽

pp. 538 ◽

Cited By ~ 6

Author(s):

Ma ◽

Zhang ◽

Xiao ◽

Yang ◽

Liu ◽

...

Keyword(s):

Bacillus Thuringiensis ◽

Spodoptera Litura ◽

Cooperative Effect ◽

Membrane Insertion ◽

Good Position ◽

Binding Region ◽

Toxin Binding ◽

Cytotoxicity Assays ◽

Cry1ac Toxin ◽

Abcc2 Transporter

Bacillus thuringiensis Cry1Ac toxin binds to midgut proteins, as cadherin (CAD) and ABCC2 transporter, to form pores leading to larval death. In cell lines, co-expression of CAD and ABCC2 enhance Cry1Ac toxicity significantly, but the mechanism remains elusive. Here, we show that the expression of Helicoverpa armigera CAD (HaCAD-GFP) in Hi5 cells induces susceptibility to Cry1Ac and enhanced Cry1Ac toxicity when co-expressed with H. armigera ABCC2 (HaABCC2-GFP), since Cry1Ac toxicity increased 735-fold compared to Hi5 cells expressing HaCAD-GFP alone or 28-fold compared to HaABCC2-GFP alone. In contrast, the expression of the Spodoptera litura CAD (SlCAD-GFP) in Hi5 cells did not induce susceptibility to Cry1Ac nor it potentiated Cry1Ac toxicity with HaABCC2-GFP. To identify the CAD regions involved in the enhancement of Cry1Ac toxicity with ABCC2, the different CAD domains were replaced between SlCAD-GFP and HaCad-GFP proteins, and cytotoxicity assays were performed in Hi5 cells in the absence or presence of HaABCC2-GFP. The HaCAD toxin-binding region (TB), specifically the CAD repeat-11, was necessary to enhance Cry1Ac toxicity with ABCC2. We propose that CAD TB is involved in recruiting Cry1Ac to localize it in a good position for its interaction with the ABCC2, resulting in efficient toxin membrane insertion enhancing Cry1Ac toxicity.

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