RNAI is a non-coding RNA that's an antisense repressor of the replication of some E. coli plasmids, including ColE1. Plasmid replication is usually initiated by RNAII, which acts as a primer by binding to its template DNA. The complementary RNAI binds RNAII prohibiting it from its initiation role. The rate of degradation of RNAI is therefore a major factor in control of plasmid replication. This rate of degradation is aided by the pcnB (plasmid copy number B) gene product, which polyadenylates… (More on Rnai)