title: Heat-inactivation of plasmid-encoded CI857 repressor induces gene expression from Ind- lambda prophage in recombinant Escherichia coli.
abstract: We have observed significant cell lysis upon temperature up-shift of recombinant Escherichia coli cultures harboring CI857-repressed lambda-based expression vectors. This event, that becomes evident about 30-40 min after the heat shock, takes place when using the lambda promoter system in Ind- lysogenic strains, but not in others commonly employed for recombinant gene expression. These results strongly suggest that the thermosensitive CI857 repressor, encoded by the expression vector, competes with CI Ind- molecules for binding to the prophage operator region, allowing for expression of lytic genes from the integrated Ind- viral genome upon temperature up-shift. Transcription of viral lytic genes does not include unspecific expression of a reporter sulA::lacZ gene fusion carried in the prophage genome. These results prompt, however, to carefully evaluate the limitations of expression systems based on pL/pR-CI857 in bacterial strains modified through lambda Ind- gene transfer vehicles.
authors.affiliation: GBF National Research Center for Biotechnology, Braunschweig, Germany.
authors.forename: F
authors.initials: F
authors.lastname: Hoffmann
authors.forename: A
authors.initials: A
authors.lastname: Arís
authors.forename: X
authors.initials: X
authors.lastname: Carbonell
authors.forename: M
authors.initials: M
authors.lastname: Rohde
authors.forename: J L
authors.initials: JL
authors.lastname: Corchero
authors.forename: U
authors.initials: U
authors.lastname: Rinas
authors.forename: A
authors.initials: A
authors.lastname: Villaverde
mesh_terms: D001433:Bacteriolysis; D010582:Bacteriophage lambda / Q000235:genetics*; D004926:Escherichia coli / Q000821:virology*; D015967:Gene Expression Regulation, Viral; D018014:Gene Transfer Techniques; D005822:Genetic Vectors; D006358:Hot Temperature; D008242:Lysogeny; D010957:Plasmids / Q000235:genetics; D011533:Proviruses / Q000235:genetics; D011994:Recombinant Proteins / Q000096:biosynthesis; D013014:SOS Response, Genetics
chemical_list: D011994:Recombinant Proteins