title: Expression of vip1/vip2 genes in Escherichia coli and Bacillus thuringiensis and the analysis of their signal peptides.
abstract: OBJECTIVE
  To determine the expression time courses and high expression level of Vip2A(c) and Vip1A(c) in Bacillus thuringiensis, and survey their insecticidal toxicity and insecticidal spectrum.
  
  
  RESULTS
  A kind of new vegetative insecticidal toxin genes encoded by a single operon from B. thuringiensis had been cloned and sequenced. The individual genes, 5-terminus truncated genes and the operon were respectively expressed in Escherichia coli. Only N-terminus deleted Vip2A(c) and Vip1A(c) proteins could be purified by Ni-NTA agarose, while others were processed and their N-terminal signal peptides were cleaved. The individual genes and the operon were also expressed in B. thuringiensis. Both proteins were mostly secreted into the cell supernatants. The expression level of Vip1A(c) was influenced because of the interruption of vip2A(c) gene on the operon. Bioassays showed that neither separate protein nor both performed any toxicity against tested lepidopteran and coleopteran insects.
  
  
  CONCLUSIONS
  Vip2A(c) and Vip1A(c) have similar secretion mechanism in E. coli and B. thuringiensis. Vip1A(c) remained its high expression level only when being expressed with vip2A(c) gene as an operon in B. thuringiensis.
  
  
  CONCLUSIONS
  Expression of vip2A(c) and vip1A(c) genes in E. coli and B. thuringiensis were investigated. This would help to make clear the secretion mechanism of VIP proteins and study the function of ADP-ribosyltransferase Vip2.
authors.affiliation: State Key Laboratory for Biocontrol and Institute of Entomology, Zhongshan (Sun Yat-sen) University, Guangzhou, P.R. China.
authors.forename: Y
authors.initials: Y
authors.lastname: Shi
authors.forename: W
authors.initials: W
authors.lastname: Xu
authors.forename: M
authors.initials: M
authors.lastname: Yuan
authors.forename: M
authors.initials: M
authors.lastname: Tang
authors.forename: J
authors.initials: J
authors.lastname: Chen
authors.forename: Y
authors.initials: Y
authors.lastname: Pang
mesh_terms: D000595:Amino Acid Sequence; D001413:Bacillus thuringiensis / Q000187:drug effects / Q000235:genetics*; D001426:Bacterial Proteins / Q000235:genetics*; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics*; D015870:Gene Expression; D007306:Insecticides / Q000494:pharmacology; D009876:Operon / Q000235:genetics; D010957:Plasmids / Q000235:genetics; D021382:Protein Sorting Signals / Q000235:genetics*; D011994:Recombinant Proteins / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D013997:Time Factors
chemical_list: D001426:Bacterial Proteins; D007306:Insecticides; D021382:Protein Sorting Signals; D011994:Recombinant Proteins