The Escherichia coli Fis protein stimulates bacteriophage lambda integrative recombination in vitro.
The Escherichia coli nucleoid-associated protein Fis was previously shown to be involved in bacteriophage lambda site-specific recombination in vivo, enhancing the levels of both integrative recombination and excisive recombination. While purified Fis protein was shown to stimulate in vitro excision, Fis appeared to have no effect on in vitro integration reactions even though a 15-fold drop in lysogenization frequency had previously been observed in fis mutants. We demonstrate here that E. coli Fis protein does stimulate integrative lambda recombination in vitro but only under specific conditions which likely mimic natural in vivo recombination more closely than the standard conditions used in vitro. In the presence of suboptimal concentrations of Int protein, Fis stimulates the rate of integrative recombination significantly. In addition, Fis enhances the recombination of substrates with nonstandard topologies which may be more relevant to the process of in vivo phage lambda recombination. These data support the hypothesis that Fis may play an essential role in lambda recombination in the host cell.
Esposito
Dominic
D
Invitrogen Corporation, Frederick, Maryland 21704, USA. domespo@ncifcrf.gov
Gerard
Gary F
GF
D010582:Bacteriophage lambda / Q000235:genetics* / Q000378:metabolism*; D001483:Base Sequence; D001665:Binding Sites; D004269:DNA, Bacterial / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D035021:Factor For Inversion Stimulation Protein / Q000235:genetics / Q000378:metabolism*; D007700:Kinetics; D008969:Molecular Sequence Data; D011995:Recombination, Genetic; D013379:Substrate Specificity
D004269:DNA, Bacterial; D029968:Escherichia coli Proteins; D035021:Factor For Inversion Stimulation Protein