Properties of Escherichia coli expressing bacteriophage P22 Abc (anti-RecBCD) proteins, including inhibition of Chi activity.
Escherichia coli strains bearing plasmids expressing phage P22 anti-RecBCD functions abc1 and abc2 were tested for the presence of recBC-like phenotypes. Abc2 induces moderate sensitivity to UV light in wild-type and recD mutant strains but severely sensitizes both recF and recJ mutants. Abc1 has little effect on UV sensitivity in wild-type or recF or recJ mutant hosts but increases the sensitivity of recD mutants to a UV dose of 20 J/m2 about 10-fold. Abc2 induces E. coli to segregate inviable cells during growth, interferes with the growth of lambda red gam chi+ and chi 0 phage (the effect is greater with chi+ phage), inhibits Chi and Chi-like activity as measured by lambda red gam crosses, and prevents SOS induction in response to nalidixic acid; Abc1 has no effect in these tests. Abc2, alone or with Abc1, does not allow the growth of lambda red gam in the presence of a P2 prophage but does not kill the P2 lysogenic host (as lambda Gam does). Finally, Abc2 inhibits conjugational recombination in wild-type cells to the level seen in recBC mutants. These data suggest that Abc2 inhibits the recombination-promoting ability of RecBCD but leaves the exonuclease functions intact.
Department of Molecular Genetics and Microbiology, University of Massachusetts, Worcester 01605.
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D017100:Bacteriophage P22 / Q000201:enzymology* / Q000235:genetics; D001483:Base Sequence; D001665:Binding Sites; D003227:Conjugation, Genetic; D004265:DNA Helicases / Q000235:genetics / Q000378:metabolism*; D004269:DNA, Bacterial / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism / Q000528:radiation effects; D029968:Escherichia coli Proteins; D043211:Exodeoxyribonuclease V; D005090:Exodeoxyribonucleases / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D009268:Nalidixic Acid / Q000494:pharmacology; D010957:Plasmids; D011995:Recombination, Genetic; D013014:SOS Response, Genetics; D014466:Ultraviolet Rays
D004269:DNA, Bacterial; D029968:Escherichia coli Proteins; D009268:Nalidixic Acid; D005090:Exodeoxyribonucleases; D043211:Exodeoxyribonuclease V; C468322:exodeoxyribonuclease V, E coli; D004265:DNA Helicases