Productive T7 infection of Escherichia coli F⁺ cells and anucleate minicells

Abstract

THE development of colivirus T7 is largely independent of host cell functions and dependent on T7-encoded enzymes, for example, T7 RNA polymerase, DNA replication enzymes, and lysozyme^1,2. In view of this relative independence, the failure to propagate in Escherichia coli cells carrying an F factor^3,4 or in anucleate minicells⁵ is particularly interesting with respect to a molecular understanding of host–virus interaction. We report here that T7 can, at a low frequency, productively infect both F⁺ cells and minicells derived from either an F⁺ or an F⁻ E. coli culture. The percentage of T7 permissive cells within an F⁺ population is dependent on the growth conditions of the culture but does not seem to be directly related to a specific phase of the cell cycle.