Packaging and transduction of non-T3 DNA by bacteriophage T3.

A defined in vitro system for packaging T3 DNA also packaged other linear DNAs, including T4, lambda, and plasmid DNAs. The packaging capacity was determined to be 40 kb (kilobase pairs) by measuring the packaged length of T4 DNA. Packaged lambda and plasmid DNAs were injected into host cells to form plaques and transductants, respectively. The yield of transducers increased by using artificially ligated plasmid oligomers. The T3 mutant in gene 3 endonuclease (T3 3-) packaged plasmid DNA during abortive infection and transduced it into the recipient. Transduction of recombinant plasmids was not affected by the presence of the terminally redundant sequence (TR sequence) but increased by 4 orders of magnitudes when the genetic right-end 2.7-kb sequences, containing gene 19 (E1) but lacking TR, were present and by 7 orders when both E1 and TR sequences were present. However, these sequences did not increase transduction of these plasmids by T7 3-. Analysis of the structure of transduced plasmid DNAs indicates that transducing particles carry head-to-tail oligomers of plasmid DNA with the same termini as those of T3 genomic DNA. The mechanism of formation of transducing particles is discussed.