Affiliation:
1. Ecogen Inc., Langhorne, Pennsylvania 19047-1810.
Abstract
The Bacillus thuringiensis CryIIIA insecticidal crystal protein (ICP) is a vegetatively expressed protein that is toxic to coleopteran insect larvae. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of the asporogenous B. thuringiensis subsp. morrisoni strain EG1351, which harbors the native cryIIIA-encoding 88-MDa plasmid, showed a 2.5-fold overproduction of the CryIIIA protein compared with that of an isogenic wild-type strain. Further studies showed that neither CryIIIA protein synthesis nor CryIIIA protein processing was affected in strain EG1351 during vegetative growth. In an attempt to characterize the EG1351 mutation by complementation of function, the hknA gene was identified and cloned from a B. thuringiensis cosmid library. Primer extension analysis of hknA mRNA in wild-type B. thuringiensis demonstrated that the hknA gene is transcribed during vegetative growth from a sigma A-like promoter. Multiple copies of either the hknA gene or the Bacillus subtilis kinA (spoIIJ) gene were shown to bypass the sporulation defect in strain EG1351 as well as a spo0F mutation in B. thuringiensis EG1634. Additional studies showed that the hknA gene was not defective in strain EG1351. The results of this study suggest that hknA encodes a novel histidine protein kinase involved in B. thuringiensis sporulation. We also propose that the CryIIIA-overproducing phenotype of strain EG1351 is most likely due to a defect in the phosphorylation of Spo0A and confirm that CryIIIA production is not dependent on sporulation.
Publisher
American Society for Microbiology
Subject
Molecular Biology,Microbiology
Cited by
47 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献