Inactivation of a newly transferred gene in recombination-deficient recipients of Escherichia coli
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The expression of a newly transferred lacZ+ gene in lacZ recipients carrying various mutations in the recA and recB genes was studied by measuring the rates of induced synthesis of β-galactosidase in zygotes formed after mating with either F′ or Hfr donors. The ability to synthesize β-galactosidase decreases with time in both recA and recB zygotes when the lacZ+ gene is transferred from an Hfr donor, but not when the lacZ gene is transferred from an F′ donor. There is no such inactivation of the newly transferred lacZ+ gene in Rec+ zygotes. We conclude that the functioning of the transferred DNA is progressively inactivated in rec recipients unless the DNA is contained in an episome such as F′.
KeywordsEscherichia Coli lacZ Gene
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