title: Cloning and expression of two homologous genes of Bacillus thuringiensis subsp. israelensis which encode 130-kilodalton mosquitocidal proteins.
abstract: Two homologous genes encoding 130-kilodalton (kDa) mosquitocidal proteins of Bacillus thuringiensis subsp. israelensis have been cloned and expressed in Escherichia coli or Bacillus subtilis or both. One of these genes, pPC130, was expressed as a lacZ transcriptional fusion in E. coli at a level sufficient to produce phase-bright inclusions, which were purified and shown to be toxic to Aedes aegypti larvae. The second gene, pCH130, was expressed at a low level in recombinant E. coli cells and was therefore cloned in B. subtilis as a transcriptional fusion of the promoter sequences corresponding to a B. thuringiensis subsp. israelensis 27-kDa delta-endotoxin (E. S. Ward, A. R. Ridley, D. J. Ellar, and J. A. Todd, J. Mol. Biol. 191:13-22, 1986) and the structural gene. Recombinant B. subtilis cells produced phase-bright inclusions during late sporulation; these were partially purified and shown to be toxic to A. aegypti larvae at an LC50 (concentration required to cause 50% mortality of larvae after 24 h of assay) which is significantly lower than that of the pPC130 protein. Neither 130-kDa protein was hemolytic under the assay conditions. Comparison of the nucleotide sequences of these two genes indicates that they share a high degree of homology in the C-terminal portions, but relatively little similarity in the N termini. In addition, significant homologies were found between the pCH130 gene and the HD-1 Dipel gene of B. thuringiensis subsp. kurstaki (H. E. Schnepf, H. C. Wong, and H. R. Whiteley, J. Biol. Chem. 260:6264-6272, 1985).
authors.affiliation: Department of Biochemistry, University of Cambridge, United Kingdom.
authors.forename: E S
authors.initials: ES
authors.lastname: Ward
authors.forename: D J
authors.initials: DJ
authors.lastname: Ellar
mesh_terms: D000330:Aedes; D000595:Amino Acid Sequence; D000818:Animals; D001412:Bacillus subtilis / Q000235:genetics; D001413:Bacillus thuringiensis / Q000235:genetics*; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D001427:Bacterial Toxins; D001483:Base Sequence; D003001:Cloning, Molecular; D003429:Cross Reactions; D004262:DNA Restriction Enzymes; D004731:Endotoxins / Q000235:genetics*; D004926:Escherichia coli / Q000235:genetics; D005786:Gene Expression Regulation; D005798:Genes, Bacterial; D006460:Hemolysin Proteins; D007306:Insecticides; D009693:Nucleic Acid Hybridization; D012091:Repetitive Sequences, Nucleic Acid; D012689:Sequence Homology, Nucleic Acid; D014158:Transcription, Genetic
chemical_list: D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D001427:Bacterial Toxins; D004731:Endotoxins; D006460:Hemolysin Proteins; D007306:Insecticides; C030956:insecticidal crystal protein, Bacillus Thuringiensis; D004262:DNA Restriction Enzymes