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The expression of recombinant genes from bacteriophage lambda strong promoters triggers the SOS response in
A Arís1, J L Corchero, A Benito
1Institut de Biologia Fonamental and Departament de Genètica i Microbiologia, Universitat Autònoma de Barcelona, Bellaterra, 08193 Barcelona, Spain.
Abstract:
The production of several non-related heterologous proteins in recombinant Escherichia coli cells promotes a significant transcription of recA and sfiA SOS DNA repair genes. The activation of the SOS system occurs when the expression of plasmid-encoded genes is directed by the strong lambda lytic promoters, but not by IPTG-controlled promoters either at 37 or at 42 degrees C, and it is linked to an extensive degradation of the proteins after their synthesis. The triggering signal for the SOS response could be an important arrest of cell DNA replication observed within the first hour after the induction of recombinant gene expression. The stimulation of this DNA repair system can partially account for the toxicity exhibited by recombinant proteins on actively producing E. coli cells.