Fig. 9. Hypothetical model for the replication cycle of the mt plasmid mp1. Mp1 produces long dsDNA concatemers by a unique RC mechanism that is mainly initiated at origin dso1. During processing of the concatemers into single plasmid units, RCs or linear molecules with invasive 3′ ends are produced that allow invasion of other mp1 structures similar to phage T4. This model is compatible with structures mapped in this study.