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Mishra R, Hua G, Bagal UR, Champagne DE, Adang MJ. Anopheles gambiae strain (Ag55) cultured cells originated from Anopheles coluzzii and are phagocytic with hemocyte-like gene expression. INSECT SCIENCE 2022; 29:1346-1360. [PMID: 35358364 DOI: 10.1111/1744-7917.13036] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Revised: 02/21/2022] [Accepted: 03/07/2022] [Indexed: 06/14/2023]
Abstract
Anopheles gambiae and Anopheles coluzzii are closely related species that are predominant vectors of malaria in Africa. Recently, A. gambiae form M was renamed A. coluzzii and we now conclude on the basis of a diagnostic PCR-restriction fragment length polymorphism assay that Ag55 cells were derived from A. coluzzii. We established an Ag55 cell transcriptome, and KEGG pathway analysis showed that Ag55 cells are enriched in phagosome pathway transcripts. The Ag55 transcriptome has an abundance of specific transcripts characteristic of mosquito hemocytes. Functional E. coli bioparticle uptake experiments visualized by fluorescence microscopy and confocal microscopy and quantified by flow cytometry establish the phagocytic competence of Ag55 cells. Results from this investigation of Ag55 cell properties will guide researchers in the use and engineering of the Ag55 cell line to better enable investigations of Plasmodium, other microbes, and insecticidal toxins.
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Affiliation(s)
- Ruchir Mishra
- Department of Entomology, College of Agricultural and Environmental Sciences, University of Georgia, Athens, Georgia, USA
- Department of Entomology and Nematology, University of Florida, Gainesville, Florida, USA
| | - Gang Hua
- Department of Entomology, College of Agricultural and Environmental Sciences, University of Georgia, Athens, Georgia, USA
| | - Ujwal R Bagal
- Institute of Bioinformatics, University of Georgia, Athens, Georgia, USA
| | - Donald E Champagne
- Department of Entomology, College of Agricultural and Environmental Sciences, University of Georgia, Athens, Georgia, USA
| | - Michael J Adang
- Department of Entomology, College of Agricultural and Environmental Sciences, University of Georgia, Athens, Georgia, USA
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA
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Soares Figueiredo C, Nunes Lemes AR, Sebastião I, Desidério JA. Synergism of the Bacillus thuringiensis Cry1, Cry2, and Vip3 Proteins in Spodoptera frugiperda Control. Appl Biochem Biotechnol 2019; 188:798-809. [DOI: 10.1007/s12010-019-02952-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Accepted: 01/11/2019] [Indexed: 12/17/2022]
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3
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Soberón M, Portugal L, Garcia-Gómez BI, Sánchez J, Onofre J, Gómez I, Pacheco S, Bravo A. Cell lines as models for the study of Cry toxins from Bacillus thuringiensis. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2018; 93:66-78. [PMID: 29269111 DOI: 10.1016/j.ibmb.2017.12.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Revised: 12/15/2017] [Accepted: 12/16/2017] [Indexed: 06/07/2023]
Abstract
Cell lines have been use extensively for the study of the mode of action of different pore forming toxins produced by different bacterial species. Bacillus thuringiensis Cry toxins are not the exception and their mechanism of action has been analyzed in different cell lines. Here we review the data obtained with different cell lines, including those that are naturally susceptible to the three domain Cry toxins (3d-Cry) and other non-susceptible cell lines that have been transformed with 3d-Cry toxin binding molecules cloned from the susceptible insects. The effects on Cry toxin action after expressing different insect gut proteins, such as glycosyl-phosphatidyl-inositol (GPI) anchored proteins (like alkaline phosphatase (ALP) aminopeptidase (APN)), or trans-membrane proteins (like cadherin (CAD) or ATP-binding cassette subfamily C member 2 (ABCC2) transporter) in cell lines showed that, with few exceptions, expression of GPI-anchored proteins do not correlated with increased susceptibility to the toxin, while the expression of CAD or ABCC2 proteins correlated with induced susceptibility to Cry toxins in the transformed cells lines. Also, that the co-expression of CAD and ABCC2 transporter induced a synergistic effect in the toxicity of 3d-Cry toxins. Overall the data show that in susceptible cell lines, the 3d-Cry toxins induce pore formation that correlates with toxicity. However, the intracellular responses remain controversial since it was shown that the same 3d-Cry toxin in different cell lines activated different responses such as adenylate cyclase-PKA death response or apoptosis. Parasporins are Cry toxins that are toxic to cancer cell lines that have structural similarities with the insecticidal Cry toxins. They belong to the 3d-Cry toxin or to MTX-like Cry toxin families but also show important differences with the insecticidal Cry proteins. Some parasporins are pore-forming toxins, and some activate apoptosis. In this review we summarized the results of the different studies about the Cry toxins mode of action using cultured cell lines and discuss their relation with the studies performed in insect larvae.
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Affiliation(s)
- Mario Soberón
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apdo. Postal 510-3, Cuernavaca 62250, Morelos, Mexico.
| | - Leivi Portugal
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apdo. Postal 510-3, Cuernavaca 62250, Morelos, Mexico.
| | - Blanca-Ines Garcia-Gómez
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apdo. Postal 510-3, Cuernavaca 62250, Morelos, Mexico.
| | - Jorge Sánchez
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apdo. Postal 510-3, Cuernavaca 62250, Morelos, Mexico
| | - Janette Onofre
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apdo. Postal 510-3, Cuernavaca 62250, Morelos, Mexico
| | - Isabel Gómez
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apdo. Postal 510-3, Cuernavaca 62250, Morelos, Mexico.
| | - Sabino Pacheco
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apdo. Postal 510-3, Cuernavaca 62250, Morelos, Mexico.
| | - Alejandra Bravo
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apdo. Postal 510-3, Cuernavaca 62250, Morelos, Mexico.
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Soberón M, Monnerat R, Bravo A. Mode of Action of Cry Toxins from Bacillus thuringiensis and Resistance Mechanisms. TOXINOLOGY 2018. [DOI: 10.1007/978-94-007-6449-1_28] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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5
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Tanaka S, Endo H, Adegawa S, Iizuka A, Imamura K, Kikuta S, Sato R. Bombyx mori ABC transporter C2 structures responsible for the receptor function of Bacillus thuringiensis Cry1Aa toxin. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2017; 91:44-54. [PMID: 29128667 DOI: 10.1016/j.ibmb.2017.11.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Revised: 10/23/2017] [Accepted: 11/01/2017] [Indexed: 06/07/2023]
Abstract
Because Bombyx mori ABC transporter C2 (BmABCC2) has 1000-fold higher potential than B. mori cadherin-like protein as a receptor for Bacillus thuringiensis Cry1Aa toxin (Tanaka et al., 2013), the gate-opening ability of the latent pore under six extracellular loops (ECLs) of BmABCC2 was expected to be the reason for its higher potential (Heckel, 2012). In this study, cell swelling assays in Sf9 cells showed that BmABCC2 mutants lacking substrate-excreting activity retained receptor activity, indicating that the gate-opening activity of BmABCC2 is not responsible for Cry1Aa toxicity. The analysis of 29 BmABCC2 mutants demonstrated that 770DYWL773 of ECL 4 comprise a putative binding site to Cry1Aa. This suggests that specific toxicity of Cry1Aa toxin to a restricted range of lepidopteran insects is dependent on conservation and variation in the amino acid residues around 770DYWL773 of ECL 4 in the ABCC2.
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Affiliation(s)
- Shiho Tanaka
- Graduate School of Bio-Applications and Systems Engineering, Tokyo University of Agriculture and Technology, Naka 2-24-16, Koganei, Tokyo 184-8588, Japan
| | - Haruka Endo
- Graduate School of Bio-Applications and Systems Engineering, Tokyo University of Agriculture and Technology, Naka 2-24-16, Koganei, Tokyo 184-8588, Japan
| | - Satomi Adegawa
- Graduate School of Bio-Applications and Systems Engineering, Tokyo University of Agriculture and Technology, Naka 2-24-16, Koganei, Tokyo 184-8588, Japan
| | - Ami Iizuka
- Graduate School of Bio-Applications and Systems Engineering, Tokyo University of Agriculture and Technology, Naka 2-24-16, Koganei, Tokyo 184-8588, Japan
| | - Kazuhiro Imamura
- Graduate School of Bio-Applications and Systems Engineering, Tokyo University of Agriculture and Technology, Naka 2-24-16, Koganei, Tokyo 184-8588, Japan
| | - Shingo Kikuta
- Graduate School of Bio-Applications and Systems Engineering, Tokyo University of Agriculture and Technology, Naka 2-24-16, Koganei, Tokyo 184-8588, Japan
| | - Ryoichi Sato
- Graduate School of Bio-Applications and Systems Engineering, Tokyo University of Agriculture and Technology, Naka 2-24-16, Koganei, Tokyo 184-8588, Japan.
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Zhang Q, Hua G, Adang MJ. Effects and mechanisms of Bacillus thuringiensis crystal toxins for mosquito larvae. INSECT SCIENCE 2017; 24:714-729. [PMID: 27628909 DOI: 10.1111/1744-7917.12401] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Revised: 08/15/2016] [Accepted: 08/22/2016] [Indexed: 06/06/2023]
Abstract
Bacillus thuringiensis is a Gram-positive aerobic bacterium that produces insecticidal crystalline inclusions during sporulation phases of the mother cell. The virulence factor, known as parasporal crystals, is composed of Cry and Cyt toxins. Most Cry toxins display a common 3-domain topology. Cry toxins exert intoxication through toxin activation, receptor binding and pore formation in a suitable larval gut environment. The mosquitocidal toxins of Bt subsp. israelensis (Bti) were found to be highly active against mosquito larvae and are widely used for vector control. Bt subsp. jegathesan is another strain which possesses high potency against broad range of mosquito larvae. The present review summarizes characterized receptors for Cry toxins in mosquito larvae, and will also discuss the diversity and effects of 3-D mosquitocidal Cry toxin and the ongoing research for Cry toxin mechanisms generated from investigations of lepidopteran and dipteran larvae.
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Affiliation(s)
- Qi Zhang
- College of Plant Protection, Shenyang Agricultural University, Shenyang, China
- Department of Entomology, University of Georgia, Athens, GA, USA
| | - Gang Hua
- Department of Entomology, University of Georgia, Athens, GA, USA
| | - Michael J Adang
- Department of Entomology, University of Georgia, Athens, GA, USA
- Department of Biochemistry & Molecular Biology, University of Georgia, Athens, GA, USA
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Lemes ARN, Figueiredo CS, Sebastião I, Marques da Silva L, da Costa Alves R, de Siqueira HÁA, Lemos MVF, Fernandes OA, Desidério JA. Cry1Ac and Vip3Aa proteins from Bacillus thuringiensis targeting Cry toxin resistance in Diatraea flavipennella and Elasmopalpus lignosellus from sugarcane. PeerJ 2017; 5:e2866. [PMID: 28123906 PMCID: PMC5244881 DOI: 10.7717/peerj.2866] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Accepted: 12/06/2016] [Indexed: 01/30/2023] Open
Abstract
The biological potential of Vip and Cry proteins from Bacillus is well known and widely established. Thus, it is important to look for new genes showing different modes of action, selecting those with differentiated entomotoxic activity against Diatraea flavipennella and Elasmopalpus lignosellus, which are secondary pests of sugarcane. Therefore, Cry1 and Vip3 proteins were expressed in Escherichia coli, and their toxicities were evaluated based on bioassays using neonate larvae. Of those, the most toxic were Cry1Ac and Vip3Aa considering the LC50 values. Toxins from E. coli were purified, solubilized, trypsinized, and biotinylated. Brush Border Membrane Vesicles (BBMVs) were prepared from intestines of the two species to perform homologous and heterologous competition assays. The binding assays demonstrated interactions between Cry1Aa, Cry1Ac, and Vip3Aa toxins and proteins from the BBMV of D. flavipennella and E. lignosellus. Homologous competition assays demonstrated that binding to one of the BBMV proteins was specific for each toxin. Heterologous competition assays indicated that Vip3Aa was unable to compete for Cry1Ac toxin binding. Our results suggest that Cry1Ac and Vip3Aa may have potential in future production of transgenic sugarcane for control of D. flavipennella and E. lignosellus, but more research is needed on the potential antagonism or synergism of the toxins in these pests.
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Affiliation(s)
- Ana Rita Nunes Lemes
- Department of Biologia Aplicada á Agropecuária, Universidade Estadual Paulista, Jaboticabal, São Paulo, Brazil
| | - Camila Soares Figueiredo
- Department of Biologia Aplicada á Agropecuária, Universidade Estadual Paulista, Jaboticabal, São Paulo, Brazil
| | - Isis Sebastião
- Department of Biologia Aplicada á Agropecuária, Universidade Estadual Paulista, Jaboticabal, São Paulo, Brazil
| | | | - Rebeka da Costa Alves
- Department of Agronomia, Universidade Federal Rural de Pernambuco, Recife, Pernambuco, Brazil
| | | | - Manoel Victor Franco Lemos
- Department of Biologia Aplicada á Agropecuária, Universidade Estadual Paulista, Jaboticabal, São Paulo, Brazil
| | - Odair Aparecido Fernandes
- Departamento de Fitossanidade/FCAV/UNESP, Universidade Estadual Paulista, Jaboticabal, São Paulo, Brazil
| | - Janete Apparecida Desidério
- Department of Biologia Aplicada á Agropecuária, Universidade Estadual Paulista, Jaboticabal, São Paulo, Brazil
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Stevens T, Song S, Bruning JB, Choo A, Baxter SW. Expressing a moth abcc2 gene in transgenic Drosophila causes susceptibility to Bt Cry1Ac without requiring a cadherin-like protein receptor. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2017; 80:61-70. [PMID: 27914919 DOI: 10.1016/j.ibmb.2016.11.008] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Revised: 11/28/2016] [Accepted: 11/29/2016] [Indexed: 06/06/2023]
Abstract
Bt toxins ingested by insect pests can bind to midgut receptors and cause death, although several steps in this process remain unclear. Multiple Bt toxin receptors have been identified in Lepidoptera, including a cadherin-like protein (CaLP), which is central to several models explaining Bt toxins' mode of action. Mutations in the Plutella xylostella ATP-dependent binding cassette transporter C2 (Px-abcc2), rather than CaLP, are genetically linked with Bt Cry1Ac resistance. Here we expressed Px-abcc2 in Drosophila and performed larval bioassays to determine whether this protein acts as an effective Bt receptor. Cry1Ac had no effect on larvae expressing Px-abcc2 in salivary glands, yet larvae expressing Px-abcc2 in the midgut were highly susceptible to both Cry1Ac protoxin and trypsin activated toxin. Furthermore, the CaLP orthologue has been lost from the Drosophila genome, making this a useful system for investigating the role of CaLP peptides from Manduca sexta (CR12-MPED), which are known to act as Bt synergists in larval feeding assays. Drosophila larvae expressing Px-ABCC2 in the midgut were fed LD50 concentrations of Cry1Ac toxin or protoxin, plus purified CR12-MPED cloned from M. sexta or P. xylostella. The M. sexta CR12-MPED protein acted synergistically with Cry1Ac protoxin and activated toxin significantly more effectively than the P. xylostella peptide. This work demonstrates ABCC2 is the major functional Cry1Ac receptor for P. xylostella and the importance of CaLP proteins in Bt mode of action may vary between different lepidopteran species.
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Affiliation(s)
- Tristan Stevens
- School of Biological Sciences, University of Adelaide, 5005 Australia
| | - Sisi Song
- School of Biological Sciences, University of Adelaide, 5005 Australia
| | - John B Bruning
- School of Biological Sciences, University of Adelaide, 5005 Australia
| | - Amanda Choo
- School of Biological Sciences, University of Adelaide, 5005 Australia
| | - Simon W Baxter
- School of Biological Sciences, University of Adelaide, 5005 Australia.
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Ren XL, Jiang WL, Ma YJ, Hu HY, Ma XY, Ma Y, Li GQ. The Spodoptera exigua (Lepidoptera: Noctuidae) ABCC2 Mediates Cry1Ac Cytotoxicity and, in Conjunction with Cadherin, Contributes to Enhance Cry1Ca Toxicity in Sf9 Cells. JOURNAL OF ECONOMIC ENTOMOLOGY 2016; 109:2281-2289. [PMID: 27986933 DOI: 10.1093/jee/tow193] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 08/09/2016] [Indexed: 06/06/2023]
Abstract
In insects, the mode of Cry1A toxins action has been studied in detail and many receptors that participate in the process are known. Recent evidence has revealed that an ABC transporter (ABCC2) is involved in conferring resistance to Cry1A toxins and that ABCC2 could be a receptor of Cry1A. However, it is not known whether Cry1Ca interacts with the same receptor proteins as Cry1A. In this study, we report the cloning of an ABC transporter gene, SeABCC2b, from the midgut of Spodoptera exigua (Hübner) larvae, and its expression in Sf9 cells for a functional analysis. The addition of Cry1Ca and Cry1Ac to Sf9 cell culture caused swelling in 28.5% and 93.9% of the SeABCC2-expressing cells, respectively. In contrast, only 7.4% and 1.3% of the controls cells swelled in the presence of Cry1Ca and Cry1Ac. Thus, SeABCC2b-expressing Sf9 cells had increased susceptibility to Cry1Ca and Cry1Ac. Similarly, S. exigua cadherin (SeCad1b) expressed in Sf9 cells caused 47.1% and 1.8% of the SeCad1b-expressing cells to swell to Cry1Ca and Cry1Ac exposure. Therefore, Sf9 cells expressing SeCad1b were more sensitive to Cry1Ca than Cry1Ac. Together, our data suggest that SeABCC2b from S. exigua mediates Cry1Ac cytotoxicity and, in conjunction with SeCad1b, contributes to enhance Cry1Ca toxicity in Sf9 cells.
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Affiliation(s)
- Xiang-Liang Ren
- Institute of Cotton Research of CAAS/State Key Laboratory of Cotton Biology, Anyang, Henan 455000, China
- Education Ministry Key Laboratory of Integrated Management of Crop Diseases and Pests, College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, Jiangsu Province, China
| | - Wei-Li Jiang
- Institute of Cotton Research of CAAS/State Key Laboratory of Cotton Biology, Anyang, Henan 455000, China
| | - Ya-Jie Ma
- Institute of Cotton Research of CAAS/State Key Laboratory of Cotton Biology, Anyang, Henan 455000, China
| | - Hong-Yan Hu
- Institute of Cotton Research of CAAS/State Key Laboratory of Cotton Biology, Anyang, Henan 455000, China
| | - Xiao-Yan Ma
- Institute of Cotton Research of CAAS/State Key Laboratory of Cotton Biology, Anyang, Henan 455000, China
| | - Yan Ma
- Institute of Cotton Research of CAAS/State Key Laboratory of Cotton Biology, Anyang, Henan 455000, China
| | - Guo-Qing Li
- Education Ministry Key Laboratory of Integrated Management of Crop Diseases and Pests, College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, Jiangsu Province, China
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Tanaka S, Endo H, Adegawa S, Kikuta S, Sato R. Functional characterization ofBacillus thuringiensisCry toxin receptors explains resistance in insects. FEBS J 2016; 283:4474-4490. [DOI: 10.1111/febs.13952] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Revised: 09/09/2016] [Accepted: 11/01/2016] [Indexed: 11/28/2022]
Affiliation(s)
- Shiho Tanaka
- Graduate School of Bio-Applications and Systems Engineering; Tokyo University of Agriculture and Technology; Japan
| | - Haruka Endo
- Graduate School of Bio-Applications and Systems Engineering; Tokyo University of Agriculture and Technology; Japan
| | - Satomi Adegawa
- Graduate School of Bio-Applications and Systems Engineering; Tokyo University of Agriculture and Technology; Japan
| | - Shingo Kikuta
- Graduate School of Bio-Applications and Systems Engineering; Tokyo University of Agriculture and Technology; Japan
| | - Ryoichi Sato
- Graduate School of Bio-Applications and Systems Engineering; Tokyo University of Agriculture and Technology; Japan
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11
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Wang J, Zhang H, Wang H, Zhao S, Zuo Y, Yang Y, Wu Y. Functional validation of cadherin as a receptor of Bt toxin Cry1Ac in Helicoverpa armigera utilizing the CRISPR/Cas9 system. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2016; 76:11-17. [PMID: 27343383 DOI: 10.1016/j.ibmb.2016.06.008] [Citation(s) in RCA: 91] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Revised: 06/03/2016] [Accepted: 06/21/2016] [Indexed: 05/29/2023]
Abstract
Cadherins have been identified as receptors of Bacillus thuringiensis (Bt) Cry1A toxins in several lepidopteran insects including the cotton bollworm, Helicoverpa armigera. Disruption of the cadherin gene HaCad has been genetically linked to resistance to Bt toxin Cry1Ac in H. armigera. By using the CRISPR/Cas9 genome editing system (Clustered Regularly Interspaced Short Palindromic Repeats/CRISPR-associated protein 9), HaCad from the Cry1Ac-susceptible SCD strain of H. armigera was successfully knocked out. A single positive CRISPR event with a frame shift deletion of 4 nucleotides was identified and made homozygous to create a knockout line named SCD-Cad. Western blotting confirmed that HaCad was no longer expressed in the SCD-Cad line while an intact HaCad of 210 kDa was present in the parental SCD strain. Insecticide bioassays were used to show that SCD-Cad exhibited 549-fold resistance to Cry1Ac compared with SCD, but no significant change in susceptibility to Cry2Ab. Our results not only provide strong reverse genetics evidence for HaCad as a functional receptor of Cry1Ac, but also demonstrate that the CRISPR/Cas9 technique can act as a powerful and efficient genome editing tool to study gene function in a global agricultural pest, H. armigera.
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Affiliation(s)
- Jing Wang
- College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China.
| | - Haonan Zhang
- College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China.
| | - Huidong Wang
- College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China.
| | - Shan Zhao
- College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China.
| | - Yayun Zuo
- College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China.
| | - Yihua Yang
- College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China.
| | - Yidong Wu
- College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China.
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12
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Melo ALDA, Soccol VT, Soccol CR. Bacillus thuringiensis: mechanism of action, resistance, and new applications: a review. Crit Rev Biotechnol 2014; 36:317-26. [DOI: 10.3109/07388551.2014.960793] [Citation(s) in RCA: 134] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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13
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Xu C, Wang BC, Yu Z, Sun M. Structural insights into Bacillus thuringiensis Cry, Cyt and parasporin toxins. Toxins (Basel) 2014; 6:2732-70. [PMID: 25229189 PMCID: PMC4179158 DOI: 10.3390/toxins6092732] [Citation(s) in RCA: 93] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Revised: 08/26/2014] [Accepted: 08/28/2014] [Indexed: 11/30/2022] Open
Abstract
Since the first X-ray structure of Cry3Aa was revealed in 1991, numerous structures of B. thuringiensis toxins have been determined and published. In recent years, functional studies on the mode of action and resistance mechanism have been proposed, which notably promoted the developments of biological insecticides and insect-resistant transgenic crops. With the exploration of known pore-forming toxins (PFTs) structures, similarities between PFTs and B. thuringiensis toxins have provided great insights into receptor binding interactions and conformational changes from water-soluble to membrane pore-forming state of B. thuringiensis toxins. This review mainly focuses on the latest discoveries of the toxin working mechanism, with the emphasis on structural related progress. Based on the structural features, B. thuringiensis Cry, Cyt and parasporin toxins could be divided into three categories: three-domain type α-PFTs, Cyt toxin type β-PFTs and aerolysin type β-PFTs. Structures from each group are elucidated and discussed in relation to the latest data, respectively.
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Affiliation(s)
- Chengchen Xu
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
| | - Bi-Cheng Wang
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA.
| | - Ziniu Yu
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
| | - Ming Sun
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
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Pan ZZ, Zhu YJ, Chen Z, Ruan CQ, Xu L, Chen QX, Liu B. A protein engineering of Bacillus thuringiensis δ-endotoxin by conjugating with 4"-O-succinoyl abamectin. Int J Biol Macromol 2013; 62:211-6. [PMID: 23999013 DOI: 10.1016/j.ijbiomac.2013.08.044] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2013] [Revised: 08/21/2013] [Accepted: 08/22/2013] [Indexed: 12/23/2022]
Abstract
Conjugation of Bacillus thuringiensis δ-endotoxin (Bt toxin) with other toxins for insect pest control has been proposed as a new efficient strategy with increasing insecticidal toxicity and target range and delay the onset of insect resistance. A modified method was investigated by conjugating Bt toxin with 4"-O-succinoyl abamectin to form a new biocide which was named as BtA. 'Zero-length' cross-linker EDC in combination with NHS activated 4"-O-succinoyl abamectin and extended half-life period of active intermediate for binding to Bt toxin. The dissociation constant for 4"-O-succinoyl abamectin binding to Bt toxin was 6.44 μM by fluorescence quenching analysis. BtA showed a higher insecticidal toxicity against Plutella xylostella, while the relative-toxicity multiple of BtA to Bt toxin was calculated as 5.6. The interaction between Bt toxins with their receptors played a key role in toxicity of Bt toxins. The binding analysis showed the dissociation rate for the binding of BtA to its receptors (7.495 × 10(-3) S(-1)) was twice slower than that of Bt toxin (1.695 × 10(-2) S(-1)). The relative dissociation constant of BtA to Bt toxin was only 29% for the binding to the receptors. These results demonstrated that BtA bound to the receptor in BBMV with significantly higher affinity compared with Bt toxin.
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Affiliation(s)
- Zhi-Zhen Pan
- Agricultural Bio-Resources Institute, Fujian Academy of Agricultural Sciences, Fuzhou 350003, China
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Tanaka S, Miyamoto K, Noda H, Jurat-Fuentes JL, Yoshizawa Y, Endo H, Sato R. The ATP-binding cassette transporter subfamily C member 2 inBombyx morilarvae is a functional receptor for Cry toxins fromBacillus thuringiensis. FEBS J 2013; 280:1782-94. [DOI: 10.1111/febs.12200] [Citation(s) in RCA: 121] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2012] [Revised: 02/07/2013] [Accepted: 02/15/2013] [Indexed: 01/15/2023]
Affiliation(s)
- Shiho Tanaka
- Graduate School of Bio-Applications and Systems Engineering; Tokyo University of Agriculture and Technology; Japan
| | - Kazuhisa Miyamoto
- National Institute of Agrobiological Sciences; Tsukuba; Ibaraki; Japan
| | - Hiroaki Noda
- National Institute of Agrobiological Sciences; Tsukuba; Ibaraki; Japan
| | | | - Yasutaka Yoshizawa
- Graduate School of Bio-Applications and Systems Engineering; Tokyo University of Agriculture and Technology; Japan
| | - Haruka Endo
- Graduate School of Bio-Applications and Systems Engineering; Tokyo University of Agriculture and Technology; Japan
| | - Ryoichi Sato
- Graduate School of Bio-Applications and Systems Engineering; Tokyo University of Agriculture and Technology; Japan
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Bergamasco V, Mendes D, Fernandes O, Desidério J, Lemos M. Bacillus thuringiensis Cry1Ia10 and Vip3Aa protein interactions and their toxicity in Spodoptera spp. (Lepidoptera). J Invertebr Pathol 2013; 112:152-8. [DOI: 10.1016/j.jip.2012.11.011] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2012] [Revised: 10/14/2012] [Accepted: 11/17/2012] [Indexed: 12/15/2022]
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Cry1Aa binding to the cadherin receptor does not require conserved amino acid sequences in the domain II loops. Biosci Rep 2012; 33:103-12. [PMID: 23145814 PMCID: PMC3546355 DOI: 10.1042/bsr20120113] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Characterizing the binding mechanism of Bt (Bacillus thuringiensis) Cry toxin to the cadherin receptor is indispensable to understanding the specific insecticidal activity of this toxin. To this end, we constructed 30 loop mutants by randomly inserting four serial amino acids covering all four receptor binding loops (loops α8, 1, 2 and 3) and analysed their binding affinities for Bombyx mori cadherin receptors via Biacore. High binding affinities were confirmed for all 30 mutants containing loop sequences that differed from those of wild-type. Insecticidal activities were confirmed in at least one mutant from loops 1, 2 and 3, suggesting that there is no critical amino acid sequence for the binding of the four loops to BtR175. When two mutations at different loops were integrated into one molecule, no reduction in binding affinity was observed compared with wild-type sequences. Based on these results, we discussed the binding mechanism of Cry toxin to cadherin protein.
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Fujii Y, Tanaka S, Otsuki M, Hoshino Y, Endo H, Sato R. Affinity Maturation of Cry1Aa Toxin to the Bombyx mori Cadherin-Like Receptor by Directed Evolution. Mol Biotechnol 2012; 54:888-99. [DOI: 10.1007/s12033-012-9638-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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Vachon V, Laprade R, Schwartz JL. Current models of the mode of action of Bacillus thuringiensis insecticidal crystal proteins: A critical review. J Invertebr Pathol 2012; 111:1-12. [DOI: 10.1016/j.jip.2012.05.001] [Citation(s) in RCA: 283] [Impact Index Per Article: 23.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2012] [Revised: 05/01/2012] [Accepted: 05/03/2012] [Indexed: 12/29/2022]
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Soberón M, Pardo L, Muñóz-Garay C, Sánchez J, Gómez I, Porta H, Bravo A. Pore formation by Cry toxins. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2010; 677:127-42. [PMID: 20687486 DOI: 10.1007/978-1-4419-6327-7_11] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Bacillus thuringiensis (Bt) bacteria produce insecticidal Cry and Cyt proteins used in the biological control of different insect pests. In this review, we will focus on the 3d-Cry toxins that represent the biggest group of Cry proteins and also on Cyt toxins. The 3d-Cry toxins are pore-forming toxins that induce cell death by forming ionic pores into the membrane of the midgut epithelial cells in their target insect. The initial steps in the mode of action include ingestion of the protoxin, activation by midgut proteases to produce the toxin fragment and the interaction with the primary cadherin receptor. The interaction of the monomeric CrylA toxin with the cadherin receptor promotes an extra proteolytic cleavage, where helix alpha-1 of domain I is eliminated and the toxin oligomerization is induced, forming a structure of 250 kDa. The oligomeric structure binds to a secondary receptor, aminopeptidase N or alkaline phosphatase. The secondary receptor drives the toxin into detergent resistant membrane microdomains formingpores that cause osmotic shock, burst of the midgut cells and insect death. Regarding to Cyt toxins, these proteins have a synergistic effect on the toxicity of some Cry toxins. Cyt proteins are also proteolytic activated in the midgut lumen of their target, they bind to some phospholipids present in the mosquito midgut cells. The proposed mechanism of synergism between Cry and Cyt toxins is that Cyt1Aa function as a receptor for Cry toxins. The Cyt1A inserts into midgut epithelium membrane and exposes protein regions that are recognized by Cry11Aa. It was demonstrated that this interaction facilitates the oligomerization of Cry11Aa and also its pore formation activity.
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Affiliation(s)
- Mario Soberón
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Mexico City, Mexico
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21
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Fabrick J, Oppert C, Lorenzen MD, Morris K, Oppert B, Jurat-Fuentes JL. A novel Tenebrio molitor cadherin is a functional receptor for Bacillus thuringiensis Cry3Aa toxin. J Biol Chem 2009; 284:18401-10. [PMID: 19416969 DOI: 10.1074/jbc.m109.001651] [Citation(s) in RCA: 92] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Cry toxins produced by the bacterium Bacillus thuringiensis are effective biological insecticides. Cadherin-like proteins have been reported as functional Cry1A toxin receptors in Lepidoptera. Here we present data that demonstrate that a coleopteran cadherin is a functional Cry3Aa toxin receptor. The Cry3Aa receptor cadherin was cloned from Tenebrio molitor larval midgut mRNA, and the predicted protein, TmCad1, has domain structure and a putative toxin binding region similar to those in lepidopteran cadherin B. thuringiensis receptors. A peptide containing the putative toxin binding region from TmCad1 bound specifically to Cry3Aa and promoted the formation of Cry3Aa toxin oligomers, proposed to be mediators of toxicity in lepidopterans. Injection of TmCad1-specific double-stranded RNA into T. molitor larvae resulted in knockdown of the TmCad1 transcript and conferred resistance to Cry3Aa toxicity. These data demonstrate the functional role of TmCad1 as a Cry3Aa receptor in T. molitor and reveal similarities between the mode of action of Cry toxins in Lepidoptera and Coleoptera.
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Affiliation(s)
- Jeff Fabrick
- United States Department of Agriculture Agricultural Research Service United States Arid-Land Agricultural Research Center, Maricopa, Arizona 85238, USA
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Broderick NA, Robinson CJ, McMahon MD, Holt J, Handelsman J, Raffa KF. Contributions of gut bacteria to Bacillus thuringiensis-induced mortality vary across a range of Lepidoptera. BMC Biol 2009; 7:11. [PMID: 19261175 PMCID: PMC2653032 DOI: 10.1186/1741-7007-7-11] [Citation(s) in RCA: 111] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2008] [Accepted: 03/04/2009] [Indexed: 12/27/2022] Open
Abstract
Background Gut microbiota contribute to the health of their hosts, and alterations in the composition of this microbiota can lead to disease. Previously, we demonstrated that indigenous gut bacteria were required for the insecticidal toxin of Bacillus thuringiensis to kill the gypsy moth, Lymantria dispar. B. thuringiensis and its associated insecticidal toxins are commonly used for the control of lepidopteran pests. A variety of factors associated with the insect host, B. thuringiensis strain, and environment affect the wide range of susceptibilities among Lepidoptera, but the interaction of gut bacteria with these factors is not understood. To assess the contribution of gut bacteria to B. thuringiensis susceptibility across a range of Lepidoptera we examined larval mortality of six species in the presence and absence of their indigenous gut bacteria. We then assessed the effect of feeding an enteric bacterium isolated from L. dispar on larval mortality following ingestion of B. thuringiensis toxin. Results Oral administration of antibiotics reduced larval mortality due to B. thuringiensis in five of six species tested. These included Vanessa cardui (L.), Manduca sexta (L.), Pieris rapae (L.) and Heliothis virescens (F.) treated with a formulation composed of B. thuringiensis cells and toxins (DiPel), and Lymantria dispar (L.) treated with a cell-free formulation of B. thuringiensis toxin (MVPII). Antibiotics eliminated populations of gut bacteria below detectable levels in each of the insects, with the exception of H. virescens, which did not have detectable gut bacteria prior to treatment. Oral administration of the Gram-negative Enterobacter sp. NAB3, an indigenous gut resident of L. dispar, restored larval mortality in all four of the species in which antibiotics both reduced susceptibility to B. thuringiensis and eliminated gut bacteria, but not in H. virescens. In contrast, ingestion of B. thuringiensis toxin (MVPII) following antibiotic treatment significantly increased mortality of Pectinophora gossypiella (Saunders), which was also the only species with detectable gut bacteria that lacked a Gram-negative component. Further, mortality of P. gossypiella larvae reared on diet amended with B. thuringiensis toxin and Enterobacter sp. NAB3 was generally faster than with B. thuringiensis toxin alone. Conclusion This study demonstrates that in some larval species, indigenous gut bacteria contribute to B. thuringiensis susceptibility. Moreover, the contribution of enteric bacteria to host mortality suggests that perturbations caused by toxin feeding induce otherwise benign gut bacteria to exert pathogenic effects. The interaction between B. thuringiensis and the gut microbiota of Lepidoptera may provide a useful model with which to identify the factors involved in such transitions.
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Hua G, Zhang R, Abdullah MAF, Adang MJ. Anopheles gambiae cadherin AgCad1 binds the Cry4Ba toxin of Bacillus thuringiensis israelensis and a fragment of AgCad1 synergizes toxicity. Biochemistry 2008; 47:5101-10. [PMID: 18407662 DOI: 10.1021/bi7023578] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A midgut cadherin AgCad1 cDNA was cloned from Anopheles gambiae larvae and analyzed for its possible role as a receptor for the Cry4Ba toxin of Bacillus thuringiensis strain israelensis. The AgCad1 cadherin encodes a putative 1735-residue protein organized into an extracellular region of 11 cadherin repeats (CR) and a membrane-proximal extracellular domain (MPED). AgCad1 mRNA was detected in midgut of larvae by polymerase chain reaction (PCR). The AgCad1 protein was localized, by immunochemistry of sectioned larvae, predominately to the microvilli in posterior midgut. The localization of Cry4Ba binding was determined by the same technique, and toxin bound microvilli in posterior midgut. The AgCad1 protein was present in brush border membrane fractions prepared from larvae, and Cry4Ba toxin bound the same-sized protein on blots of those fractions. The AgCad1 protein was expressed transiently in Drosophila melanogaster Schneider 2 (S2) cells. 125I-Cry4Ba toxin bound AgCad1 from S2 cells in a competitive manner. Cry4Ba bound to beads extracted 200 kDa AgCad1 and a 29 kDa fragment of AgCad1 from S2 cells. A peptide containing the AgCad1 region proximal to the cell (CR11-MPED) was expressed in Escherichia coli. Although Cry4Ba showed limited binding to CR11-MPED, the peptide synergized the toxicity of Cry4Ba to larvae. AgCad1 in the larval brush border is a binding protein for Cry4Ba toxin. On the basis of binding results and CR11-MPED synergism of Cry4Ba toxicity, AgCad1 is probably a Cry4Ba receptor.
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Affiliation(s)
- Gang Hua
- Department of Entomology, University of Georgia, Athens, Georgia 30602-2603, USA
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24
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Investigating the properties of Bacillus thuringiensis Cry proteins with novel loop replacements created using combinatorial molecular biology. Appl Environ Microbiol 2008; 74:3497-511. [PMID: 18408065 DOI: 10.1128/aem.02844-07] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Cry proteins are a large family of crystalline toxins produced by Bacillus thuringiensis. Individually, the family members are highly specific, but collectively, they target a diverse range of insects and nematodes. Domain II of the toxins is important for target specificity, and three loops at its apex have been studied extensively. There is considerable interest in determining whether modifications in this region may lead to toxins with novel specificity or potency. In this work, we studied the effect of loop substitution on toxin stability and specificity. For this purpose, sequences derived from antibody complementarity-determining regions (CDR) were used to replace native domain II apical loops to create "Crybodies." Each apical loop was substituted either individually or in combination with a library of third heavy-chain CDR (CDR-H3) sequences to create seven distinct Crybody types. An analysis of variants from each library indicated that the Cry1Aa framework can tolerate considerable sequence diversity at all loop positions but that some sequence combinations negatively affect structural stability and protease sensitivity. CDR-H3 substitution showed that loop position was an important determinant of insect toxicity: loop 2 was essential for activity, whereas the effects of substitutions at loop 1 and loop 3 were sequence dependent. Unexpectedly, differences in toxicity did not correlate with binding to cadherins--a major class of toxin receptors--since all Crybodies retained binding specificity. Collectively, these results serve to better define the role of the domain II apical loops as determinants of specificity and establish guidelines for their modification.
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Chen J, Hua G, Jurat-Fuentes JL, Abdullah MA, Adang MJ. Synergism of Bacillus thuringiensis toxins by a fragment of a toxin-binding cadherin. Proc Natl Acad Sci U S A 2007; 104:13901-6. [PMID: 17724346 PMCID: PMC1955780 DOI: 10.1073/pnas.0706011104] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
The insecticidal crystal proteins produced by Bacillus thuringiensis (Bt) are broadly used to control insect pests with agricultural importance. The cadherin Bt-R(1) is a binding protein for Bt Cry1A toxins in midgut epithelia of tobacco hornworm (Manduca sexta). We previously identified the Bt-R(1) region most proximal to the cell membrane (CR12-MPED) as the essential binding region required for Cry1Ab-mediated cytotoxicity. Here, we report that a peptide containing this region expressed in Escherichia coli functions as a synergist of Cry1A toxicity against lepidopteran larvae. Far-UV circular dichroism and (1)H-NMR spectroscopy confirmed that our purified CR12-MPED peptide mainly consisted of beta-strands and random coils with unfolded structure. CR12-MPED peptide bound brush border membrane vesicles with high affinity (K(d) = 32 nM) and insect midgut microvilli but did not alter Cry1Ab or Cry1Ac binding localization in the midgut. By BIAcore analysis we demonstrate that Cry1Ab binds CR12-MPED at high (9 nM)- and low (1 microM)-affinity sites. CR12-MPED-mediated Cry1A toxicity enhancement was significantly reduced when the high-affinity Cry1A-binding epitope ((1416)GVLTLNIQ(1423)) within the peptide was altered. Because the mixtures of low Bt toxin dose and CR12-MPED peptide effectively control target insect pests, our discovery has important implications related to the use of this peptide to enhance insecticidal activity of Bt toxin-based biopesticides and transgenic Bt crops.
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Affiliation(s)
| | | | | | | | - Michael J. Adang
- Departments of *Entomology and
- Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602-2603
- To whom correspondence should be addressed. E-mail:
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26
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Pigott CR, Ellar DJ. Role of receptors in Bacillus thuringiensis crystal toxin activity. Microbiol Mol Biol Rev 2007; 71:255-81. [PMID: 17554045 PMCID: PMC1899880 DOI: 10.1128/mmbr.00034-06] [Citation(s) in RCA: 402] [Impact Index Per Article: 23.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Bacillus thuringiensis produces crystalline protein inclusions with insecticidal or nematocidal properties. These crystal (Cry) proteins determine a particular strain's toxicity profile. Transgenic crops expressing one or more recombinant Cry toxins have become agriculturally important. Individual Cry toxins are usually toxic to only a few species within an order, and receptors on midgut epithelial cells have been shown to be critical determinants of Cry specificity. The best characterized of these receptors have been identified for lepidopterans, and two major receptor classes have emerged: the aminopeptidase N (APN) receptors and the cadherin-like receptors. Currently, 38 different APNs have been reported for 12 different lepidopterans. Each APN belongs to one of five groups that have unique structural features and Cry-binding properties. While 17 different APNs have been reported to bind to Cry toxins, only 2 have been shown to mediate toxin susceptibly in vivo. In contrast, several cadherin-like proteins bind to Cry toxins and confer toxin susceptibility in vitro, and disruption of the cadherin gene has been associated with toxin resistance. Nonetheless, only a small subset of the lepidopteran-specific Cry toxins has been shown to interact with cadherin-like proteins. This review analyzes the interactions between Cry toxins and their receptors, focusing on the identification and validation of receptors, the molecular basis for receptor recognition, the role of the receptor in resistant insects, and proposed models to explain the sequence of events at the cell surface by which receptor binding leads to cell death.
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Affiliation(s)
- Craig R Pigott
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1GA, United Kingdom
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Higuchi M, Haginoya K, Yamazaki T, Miyamoto K, Katagiri T, Tomimoto K, Shitomi Y, Hayakawa T, Sato R, Hori H. Binding of Bacillus thuringiensis Cry1A toxins to brush border membrane vesicles of midgut from Cry1Ac susceptible and resistant Plutella xylostella. Comp Biochem Physiol B Biochem Mol Biol 2007; 147:716-24. [PMID: 17543562 DOI: 10.1016/j.cbpb.2007.04.013] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2006] [Revised: 04/18/2007] [Accepted: 04/18/2007] [Indexed: 11/24/2022]
Abstract
Plutella xylostella strain resistant (PXR) to Bacillus thuringiensis Cry1Ac toxin was not killed at even more than 1000 microg Cry1Ac/g diet but killed by Cry1Ab at 0.5 microg/g diet. In contrast, susceptible strain (PXS) was killed by Cry1Ac at 1 microg/g diet. Cy3-labeld Cry1A(s) binding to brush border membrane vesicles (BBMV) prepared from both strains were analyzed with direct binding assay. The Kd value of Cry1Aa to both BBMV was almost identical: 213.2 and 205.8 nM, and 263.5 and 265.0 nM for Cry1Ac. The highest Kd values were in Cry1Ab which showed most effective insecticidal activity in PXS and PXR, 2126 and 2463 nM, respectively. These results clearly showed that the BBMV from PXR and PXS could equally bind to Cry1Ac. The binding between BBMV and Cy3-labeled Cry1Ac was inhibited only by anti-175 kDa cadherin-like protein (CadLP) and -252 kDa protein antisera, but not by anti-120 kDa aminopeptidase. This supports that resistance in PXR resulted from the abortion of pore formation after the binding of Cry1Ac to the BBMV. And furthermore, the importance of 175K CadLP and P252 proteins in those bindings was suggested. We briefly discuss possible mechanisms of the resistance.
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Affiliation(s)
- Masahiro Higuchi
- Graduate School of Science and Technology, Niigata University, Niigata 950-2181, Japan
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Borovsky D, Rabindran S, Dawson WO, Powell CA, Iannotti DA, Morris TJ, Shabanowitz J, Hunt DF, DeBondt HL, DeLoof A. Expression of Aedes trypsin-modulating oostatic factor on the virion of TMV: A potential larvicide. Proc Natl Acad Sci U S A 2006; 103:18963-8. [PMID: 17148608 PMCID: PMC1748160 DOI: 10.1073/pnas.0606146103] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2005] [Indexed: 11/18/2022] Open
Abstract
We report the engineering of the surface of the tobacco mosaic virus (TMV) virion with a mosquito decapeptide hormone, trypsin-modulating oostatic factor (TMOF). The TMV coat protein (CP) was fused to TMOF at the C terminus by using a read-through, leaky stop codon that facilitated expression of CP and chimeric CP-TMOF (20:1 ratio) that were coassembled into virus particles in infected Nicotiana tabacum. Plants that were infected with the hybrid TMV RNA accumulated TMOF to levels of 1.3% of total soluble protein. Infected tobacco leaf discs that were fed to Heliothis virescens fourth-instar larvae stunted their growth and inhibited trypsin and chymotrypsin activity in their midgut. Purified CP-TMOF virions fed to mosquito larvae stopped larval growth and caused death. Because TMV has a wide host range, expressing TMV-TMOF in plants can be used as a general method to protect them against agricultural insect pests and to control vector mosquitoes.
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Affiliation(s)
- Dov Borovsky
- Florida Medical Entomology Laboratory, University of Florida-Institute of Food and Agricultural Sciences (IFAS), 200 Ninth Street Southeast, Vero Beach, FL 32962-4699, USA.
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Aimanova KG, Zhuang M, Gill SS. Expression of Cry1Ac cadherin receptors in insect midgut and cell lines. J Invertebr Pathol 2006; 92:178-87. [PMID: 16797582 DOI: 10.1016/j.jip.2006.04.011] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2005] [Accepted: 02/06/2006] [Indexed: 01/26/2023]
Abstract
Cadherin-like proteins have been identified as putative receptors for the Bacillus thuringiensis Cry1A proteins in Heliothis virescens and Manduca sexta. Immunohistochemistry showed the cadherin-like proteins are present in the insect midgut apical membrane, which is the target site of Cry toxins. This subcellular localization is distinct from that of classical cadherins, which are usually present in cell-cell junctions. Immunoreactivity of the cadherin-like protein in the insect midgut was enhanced by Cry1Ac ingestion. We also generated a stable cell line Flp-InT-REX-293/Full-CAD (CAD/293) that expressed the H. virescens cadherin. As expected, the cadherin-like protein was mainly localized in the cell membrane. Interestingly, toxin treatment of CAD/293 cells caused this protein to relocalize to cell membrane subdomains. In addition, expression of H. virescens cadherin-like protein affects cell-cell contact and cell membrane integrity when the cells are exposed to activated Cry1Ab/Cry1Ac.
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Affiliation(s)
- Karlygash G Aimanova
- Department of Cell Biology and Neuroscience, University of California, Riverside, CA 92521, USA
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30
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Jurat-Fuentes JL, Adang MJ. Cry toxin mode of action in susceptible and resistant Heliothis virescens larvae. J Invertebr Pathol 2006; 92:166-71. [PMID: 16797583 DOI: 10.1016/j.jip.2006.01.010] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2005] [Accepted: 01/20/2006] [Indexed: 02/04/2023]
Abstract
Many pest insect species are effectively controlled by Bacillus thuringiensis (Bt) Cry toxins delivered in plants and biopesticides. Since the insect midgut epithelium contains receptors and other molecules that determine Bt toxicity, characterization of these molecules is necessary for sustained usage of Bt toxins. Studies of Bt susceptible and resistant strains of Heliothis virescens have provided insights into resistance mechanisms and toxin receptors. For example, the first gene identified as involved in high levels of Cry1Ac resistance in H. virescens encodes a cadherin-like protein, a functional Cry1A receptor in Lepidoptera. This manuscript discusses the most updated information on the mode of action of Cry1A toxins obtained from the characterization of resistant mechanisms in H. virescens strains. Our studies are focused on biochemical and molecular comparison of a susceptible and three resistant H. virescens strains to identify alterations that correlate with toxin resistance. Following this approach we have been able to identify an alkaline phosphatase (HvALP) as a potential receptor and tested the utility of this protein as a marker for resistance to Cry1Ac. Comparison of brush border proteomes from susceptible and resistant larvae has allowed us to identify additional molecules directly involved in the toxicity process.
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Hussein HM, Habustová O, Sehnal F. Beetle-specific Bacillus thuringiensis Cry3Aa toxin reduces larval growth and curbs reproduction in Spodoptera littoralis (Boisd.). PEST MANAGEMENT SCIENCE 2005; 61:1186-92. [PMID: 16152673 DOI: 10.1002/ps.1112] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Application of Bacillus thuringiensis tenebrionis (Bt) and expression of the Bt protein Cry3Aa in genetically modified crops are used for targeted control of the Colorado potato beetle Leptinotarsa decemlineata (Say). The Cry3A proteins are selectively toxic for the beetles but the present study describes effects of Cry3Aa on the Egyptian armyworm, Spodoptera littoralis (Boisduval). Cry3Aa expressed in potatoes or added to an agar-base wheat-germ diet reduced the growth of S. littoralis caterpillars and the fertility of adults. The effect of 1.4 mg kg(-1) Cry3Aa in potato leaves was comparable with that of 3.3 mg kg(-1) in the diet. This difference in activity was correlated with better digestibility and higher conversion efficiency of the diet that also supported higher reproduction rate: S. littoralis grown on the potatoes reached a similar size to those on the diet but laid only 702 instead of 1077 eggs per female. Cry3Aa consumption reduced body growth as a consequence of lower food intake without significantly affecting food digestibility and the conversion efficiency of nutrients. The 11% and 5% body weight reductions caused by 1.4 mg kg(-1) Cry3Aa in potatoes and 3.3 mg kg(-1) in the diet, respectively, were associated with 74% and 65% reduction in the number of progeny; S littoralis grown on a diet with 9.1 mg kg(-1) Cry3Aa were 10% smaller and produced no viable progeny. These data suggest that the curtailment of reproduction was not caused by a general shortage of nutrient reserves but by a more direct Cry3Aa effect on the reproduction process.
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Affiliation(s)
- Hany M Hussein
- Institute of Entomology, Academy of Sciences, Branisovská 31, 37005 Ceské Budejovice, Czech Republic
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32
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Molecular approaches for identification and construction of novel insecticidal genes for crop protection. World J Microbiol Biotechnol 2005. [DOI: 10.1007/s11274-005-9027-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Baxter SW, Zhao JZ, Gahan LJ, Shelton AM, Tabashnik BE, Heckel DG. Novel genetic basis of field-evolved resistance to Bt toxins in Plutella xylostella. INSECT MOLECULAR BIOLOGY 2005; 14:327-34. [PMID: 15926902 DOI: 10.1111/j.1365-2583.2005.00563.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Insecticidal toxins from Bacillus thuringiensis (Bt) are widely used to control pest insects, but evolution of resistance threatens their continued efficacy. The most common type of Bt resistance ('Mode 1') is characterized by recessive inheritance, > 500-fold resistance to at least one Cry1A toxin, negligible cross-resistance to Cry1C, and reduced binding of Bt toxins to midgut membrane target sites. Mutations affecting a Cry1A-binding midgut cadherin protein are linked to laboratory-selected Mode 1 resistance in Heliothis virescens and Pectinophora gossypiella. Here we show that field-evolved Mode 1 resistance in the diamondback moth, Plutella xylostella, has a different genetic basis, indicating that screening for resistance in the field should not be restricted to a previously proposed DNA-based search for cadherin mutations.
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Affiliation(s)
- S W Baxter
- CESAR, Department of Genetics, University of Melbourne, Victoria, Australia
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Chen J, Brown MR, Hua G, Adang MJ. Comparison of the localization of Bacillus thuringiensis Cry1A δ-endotoxins and their binding proteins in larval midgut of tobacco hornworm, Manduca sexta. Cell Tissue Res 2005; 321:123-9. [PMID: 15902495 DOI: 10.1007/s00441-005-1124-6] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2005] [Accepted: 03/18/2005] [Indexed: 11/30/2022]
Abstract
Tobacco hornworm, Manduca sexta, is a model insect for studying the action of Bacillus thuringiensis (Bt) Cry toxins on lepidopterans. The proteins, which bind Bt toxins to midgut epithelial cells, are key factors involved in the insecticidal functions of the toxins. Three Cry1A-binding proteins, viz., aminopeptidase N (APN), the cadherin-like Bt-R1, and membrane-type alkaline phosphatase (m-ALP), were localized, by immunohistochemistry, in sections from the anterior, middle, and posterior regions of the midgut from second instar M. sexta larvae. Both APN and m-ALP were distributed predominantly along microvilli in the posterior region and to a lesser extent on the apical tip of microvilli in the anterior and middle regions. Bt-R1 was localized at the base of microvilli in the anterior region, over the entire microvilli in the middle region, and at both the apex and base of microvilli in the posterior region. The localization of rhodamine-labeled Cry1Aa, Cry1Ab, and Cry1Ac binding was determined on sections from the same midgut regions. Cry1Aa and Cry1Ab bound to the apical tip of microvilli almost equally in all midgut regions. Binding of Cry1Ac was much stronger in the posterior region than in the anterior and middle regions. Thus, binding sites for Bt proteins and Cry1A toxins are co-localized on the microvilli of M. sexta midgut epithelial cells.
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Affiliation(s)
- Jiang Chen
- Department of Entomology, University of Georgia, Athens, GA 30602-2603, USA
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Mucha J, Domlatil J, Lochnit G, Rendić D, Paschinger K, HINTERKöRNER G, Hofinger A, Kosma P, Wilson I. The Drosophila melanogaster homologue of the human histo-blood group Pk gene encodes a glycolipid-modifying alpha1,4-N-acetylgalactosaminyltransferase. Biochem J 2005; 382:67-74. [PMID: 15130086 PMCID: PMC1133916 DOI: 10.1042/bj20040535] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2004] [Revised: 04/29/2004] [Accepted: 05/07/2004] [Indexed: 11/17/2022]
Abstract
Insects express arthro-series glycosphingolipids, which contain an alpha1,4-linked GalNAc residue. To determine the genetic basis for this linkage, we cloned a cDNA (CG17223) from Drosophila melanogaster encoding a protein with homology to mammalian alpha1,4-glycosyltransferases and expressed it in the yeast Pichia pastoris. Culture supernatants from the transformed yeast were found to display a novel UDP-GalNAc:GalNAcbeta1,4GlcNAcbeta1-R alpha-N-acetylgalactosaminyltransferase activity when using either a glycolipid, p-nitrophenylglycoside or an N-glycan carrying one or two terminal beta-N-acetylgalactosamine residues. NMR and MS in combination with glycosidase digestion and methylation analysis indicate that the cloned cDNA encodes an alpha1,4-N-acetylgalactosaminyltransferase. We hypothesize that this enzyme and its orthologues in other insects are required for the biosynthesis of the N5a and subsequent members of the arthro-series of glycolipids as well as of N-glycan receptors for Bacillus thuringiensis crystal toxin Cry1Ac.
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Affiliation(s)
- Ján Mucha
- *Chemický ústav, Slovenská akadémia vied, Dúbravská cesta 9, 845 38 Bratislava, Slovakia
| | - Jiří Domlatil
- †Department für Chemie, Universität für Bodenkultur, Muthgasse 18, A-1190 Wien, Austria
| | - Günter Lochnit
- ‡Institut für Biochemie, Justus-Liebig-Universität Giessen, Friedrichstrasse 24, D-35392 Giessen, Germany
| | - Dubravko Rendić
- †Department für Chemie, Universität für Bodenkultur, Muthgasse 18, A-1190 Wien, Austria
| | - Katharina Paschinger
- †Department für Chemie, Universität für Bodenkultur, Muthgasse 18, A-1190 Wien, Austria
| | - Georg HINTERKöRNER
- †Department für Chemie, Universität für Bodenkultur, Muthgasse 18, A-1190 Wien, Austria
| | - Andreas Hofinger
- †Department für Chemie, Universität für Bodenkultur, Muthgasse 18, A-1190 Wien, Austria
| | - Paul Kosma
- †Department für Chemie, Universität für Bodenkultur, Muthgasse 18, A-1190 Wien, Austria
| | - Iain B. H. Wilson
- †Department für Chemie, Universität für Bodenkultur, Muthgasse 18, A-1190 Wien, Austria
- To whom correspondence should be addressed (email )
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Bravo A, Gómez I, Conde J, Muñoz-Garay C, Sánchez J, Miranda R, Zhuang M, Gill SS, Soberón M. Oligomerization triggers binding of a Bacillus thuringiensis Cry1Ab pore-forming toxin to aminopeptidase N receptor leading to insertion into membrane microdomains. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2005; 1667:38-46. [PMID: 15533304 DOI: 10.1016/j.bbamem.2004.08.013] [Citation(s) in RCA: 266] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2004] [Revised: 08/16/2004] [Accepted: 08/30/2004] [Indexed: 11/19/2022]
Abstract
Bacillus thuringiensis Cry1A toxins, in contrast to other pore-forming toxins, bind two putative receptor molecules, aminopeptidase N (APN) and cadherin-like proteins. Here we show that Cry1Ab toxin binding to these two receptors depends on the toxins' oligomeric structure. Toxin monomeric structure binds to Bt-R1, a cadherin-like protein, that induces proteolytic processing and oligomerization of the toxin (Gomez, I., Sanchez, J., Miranda, R., Bravo A., Soberon, M., FEBS Lett. (2002) 513, 242-246), while the oligomeric structure binds APN, which drives the toxin into the detergent-resistant membrane (DRM) microdomains causing pore formation. Cleavage of APN by phospholipase C prevented the location of Cry1Ab oligomer and Bt-R1 in the DRM microdomains and also attenuates toxin insertion into membranes despite the presence of Bt-R1. Immunoprecipitation experiments demonstrated that initial Cry1Ab toxin binding to Bt-R1 is followed by binding to APN. Also, immunoprecipitation of Cry1Ab toxin-binding proteins using pure oligomeric or monomeric structures showed that APN was more efficiently detected in samples immunoprecipitated with the oligomeric structure, while Bt-R1 was preferentially detected in samples immunoprecipitated with the monomeric Cry1Ab. These data agrees with the 200-fold higher apparent affinity of the oligomer than that of the monomer to an APN enriched protein extract. Our data suggest that the two receptors interact sequentially with different structural species of the toxin leading to its efficient membrane insertion.
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Affiliation(s)
- A Bravo
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apdo. Postal 510-3, Cuernavaca 62250, Morelos, México.
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Hua G, Jurat-Fuentes JL, Adang MJ. Bt-R1a extracellular cadherin repeat 12 mediates Bacillus thuringiensis Cry1Ab binding and cytotoxicity. J Biol Chem 2004; 279:28051-6. [PMID: 15123702 DOI: 10.1074/jbc.m400237200] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The cadherin protein Bt-R(1a) is a receptor for Bacillus thuringiensis Cry1A toxins in Manduca sexta. Cry1Ab toxin is reported to bind specific epitopes located in extracellular cadherin repeat (CR) 7 and CR11 on Bt-R(1) (Gomez, B., Miranda-Rios, J., Riudino-Pinera, E., Oltean, D. I., Gill, S. S., Bravo, A., and Soberon, M. (2002) J. Biol. Chem. 277, 30137-30143; Dorsch, J. A., Candas, M., Griko, N., Maaty, W., Midboe, E., Vadlamudi, R., and Bulla, L. (2002) Insect Biochem. Mol. Biol. 32, 1025-1036). We transiently expressed CR domains of Bt-R(1a) in Drosophila melanogaster Schneider 2 (S2) cells as fusion peptides between a signal peptide and a terminal region that included membrane-proximal, membrane-spanning, and cytoplasmic domains. A domain consisting of CR11 and 12 was the minimal (125)I-Cry1Ab binding region detected under denaturing conditions. Only CR12 was essential for Cry1Ab binding and cytotoxicity to S2 cells when tested under native conditions. Under these conditions expressed CR12 bound (125)I-Cry1Ab with high affinity (K(com) = 2.9 nm). Flow cytometry assays showed that expression of CR12 conferred susceptibility to Cry1Ab in S2 cells. Derivatives of Bt-R(1a) with separate deletions of CR7, 11, and 12 were expressed in S2 cells. Only deletion of CR12 caused loss of Cry1Ab binding and cytotoxicity. These results demonstrate that CR12 is the essential Cry1Ab binding component on Bt-R(1) that mediates Cry1Ab-induced cytotoxicity.
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Affiliation(s)
- Gang Hua
- Department of Entomology, University of Georgia, Athens, GA 30602-2603, USA
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