title: Incomplete entry of bacteriophage T7 DNA into F plasmid-containing Escherichia coli.
abstract: The penetration of bacteriophage T7 DNA into F plasmid-containing Escherichia coli cells was determined by measuring Dam methylation of the entering genome. T7 strains that cannot productively infect F-containing cells fail to completely translocate their DNA into the cell before the infection aborts. The entry of the first 44% of the genome occurs normally in an F-containing cell, but the entry of the remainder is aberrant. Bypassing the normal mode of entry of the T7 genome by transfecting naked DNA into competent cells fails to suppress F exclusion of phage development. However, overexpression of various nontoxic T7 1.2 alleles from a high-copy-number plasmid or expression of T3 1.2 from a T7 genome allows phage growth in the presence of F.
authors.affiliation: Department of Microbiology, University of Texas, Austin 78712-1095, USA.
authors.forename: L R
authors.initials: LR
authors.lastname: García
authors.forename: I J
authors.initials: IJ
authors.lastname: Molineux
mesh_terms: D017123:Bacteriophage T7 / Q000235:genetics / Q000254:growth & development*; D004279:DNA, Viral / Q000235:genetics / Q000378:metabolism*; D004926:Escherichia coli / Q000821:virology*; D029968:Escherichia coli Proteins; D005144:F Factor; D015870:Gene Expression; D005814:Genes, Viral; D016679:Genome, Viral; D008745:Methylation; D009154:Mutation; D015265:Site-Specific DNA-Methyltransferase (Adenine-Specific) / Q000378:metabolism; D014162:Transfection
chemical_list: D004279:DNA, Viral; D029968:Escherichia coli Proteins; C058693:Dam methyltransferase; D015265:Site-Specific DNA-Methyltransferase (Adenine-Specific); C499294:dam protein, E coli