Heat-inactivation of plasmid-encoded CI857 repressor induces gene expression from Ind- lambda prophage in recombinant Escherichia coli.
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.
Hoffmann
F
F
GBF National Research Center for Biotechnology, Braunschweig, Germany.
Arís
A
A
Carbonell
X
X
Rohde
M
M
Corchero
J L
JL
Rinas
U
U
Villaverde
A
A
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
D011994:Recombinant Proteins