Publication Date:
2016-02-10
Description:
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.
Keywords:
Biotechnology & Synthetic Biology
Print ISSN:
0378-1097
Electronic ISSN:
1574-6968
Topics:
Biology
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