[Integration of the mini-Mu phage into multicopy plasmids]

Preparation of mini-Mu4 phage introduced into the pRP1.2 plasmid and carrying a 18 kb deletion of the central EcoRI fragment is described. The ability of the mini-Mu4 for independent transposition is demonstrated in experiments conducted for cointegrate formation (replicon fusion). The system developed is applicable to studying the mechanism of transposition, since the frequency of cointegrate formation may be descriptive of the transposition process. Frequency changes due to some factors may point to a possible influence of these factors on the mini-Mu transcription. The described mini-Mu integration into small multicopy plasmids of Col type makes it possible to conduct a simple physical analysis of structures formed in the course of transposition.