title: Cry-like genes, in an uncommon gene configuration, produce a crystal that localizes within the exosporium when expressed in an acrystalliferous strain of Bacillus thuringiensis.
abstract: Cry proteins are pesticidal toxins produced by the bacterium Bacillus thuringiensis (Bt), which aggregate in sporulating cells to form a crystal. Except in a relatively few cases, these crystals are located outside the exosporium that surrounds the spore. Bt2-56 is a strain of Bt that has the relatively uncommon characteristic of locating its Cry protein-containing crystal within the exosporium, and in association with a long, multifiber filament. With the ultimate goal of both understanding and manipulating the localization of Cry proteins within the exosporium, we sought to identify the genes coding for the exosporium-localized Cry proteins in Bt2-56. Herein we show (i) that five cry-like genes are present in the genome of Bt2-56, (ii) that two pairs of these genes show organizational similarity to a relatively uncommon gene configuration that coexpress a cry gene along with a gene whose product aids crystal formation and (iii) that when one of these two gene pairs (cry21A-cdA) is expressed in an acrystalliferous strain of Bt, crystals are formed that localize within the exosporium. In Bt ssp. finitimus, the only other strain in which crystal localization has been studied, a Cry protein needed expression of two non-cry ORFs in order to localize within the exosporium, indicating that there are some mechanistic differences for crystal localization between Bt ssp. finitimus and Bt2-56.
authors.affiliation: Department of Chemistry, The University of Texas-Pan American, Edinburg, TX 78539, USA.
authors.forename: David
authors.initials: D
authors.lastname: Ammons
authors.affiliation: Division of Information Technology, The University of Texas-Pan American, Edinburg, TX 78539, USA.
authors.forename: Graham
authors.initials: G
authors.lastname: Toal
authors.affiliation: Department of Chemistry, The University of Texas-Pan American, Edinburg, TX 78539, USA.
authors.forename: Angel
authors.initials: A
authors.lastname: Roman
authors.affiliation: Soil Laboratory, School of Biological and Agricultural Sciences, Universidad Veracruzana, Orizaba-Córdoba zone, Peñuela-Amatlán Km 1. Amatlán de los Reyes, 94945, Veracruz, México.
authors.forename: Luz I
authors.initials: LI
authors.lastname: Rojas-Avelizapa
authors.affiliation: Soil Laboratory, School of Biological and Agricultural Sciences, Universidad Veracruzana, Orizaba-Córdoba zone, Peñuela-Amatlán Km 1. Amatlán de los Reyes, 94945, Veracruz, México.
authors.forename: Antonio
authors.initials: A
authors.lastname: Ventura-Suárez
authors.affiliation: Department of Chemistry, The University of Texas-Pan American, Edinburg, TX 78539, USA joutpa@gmail.com.
authors.forename: Joanne
authors.initials: J
authors.lastname: Rampersad
mesh_terms: D001413:Bacillus thuringiensis / Q000737:chemistry / Q000235:genetics*; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics*; D061046:Biological Control Agents / Q000737:chemistry; D002473:Cell Wall / Q000737:chemistry / Q000235:genetics*; D004731:Endotoxins / Q000737:chemistry* / Q000235:genetics*; D015964:Gene Expression Regulation, Bacterial; D023061:Gene Order; D016680:Genome, Bacterial; D006460:Hemolysin Proteins / Q000737:chemistry* / Q000235:genetics*; D013171:Spores, Bacterial / Q000737:chemistry*
chemical_list: D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D061046:Biological Control Agents; D004731:Endotoxins; D006460:Hemolysin Proteins; C030956:insecticidal crystal protein, Bacillus Thuringiensis
keywords: Cry; crystal; exosporium; thuringiensis