RNAI explained

RNAI
Symbol:	RNAI
Rfam:	RF00106
Rna Type:	Gene antisense
Tax Domain:	Bacteria

RNAI is a non-coding RNA that is an antisense repressor of the replication of some E. coli plasmids, including ColE1. Plasmid replication is usually initiated by RNAII,^[1] 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 the control of plasmid replication. This rate of degradation is aided by the pcnB (plasmid copy number B) gene product,^[2] which polyadenylates the 3' end of RNAI targeting it for degradation by PNPase.^[3]

Further reading

• Cohen SN . Surprises at the 3' end of prokaryotic RNA . Cell . 80 . 6 . 829–832 . March 1995 . 7535193 . 10.1016/0092-8674(95)90284-8 . 9077296 . free .

Notes and References

1. Masukata H, Tomizawa J . Control of primer formation for ColE1 plasmid replication: conformational change of the primer transcript . Cell . 44 . 1 . 125–136 . January 1986 . 2416472 . 10.1016/0092-8674(86)90491-5 . 400406 .
2. He L, Söderbom F, Wagner EG, Binnie U, Binns N, Masters M . PcnB is required for the rapid degradation of RNAI, the antisense RNA that controls the copy number of ColE1-related plasmids . Molecular Microbiology . 9 . 6 . 1131–1142 . September 1993 . 7523833 . 10.1111/j.1365-2958.1993.tb01243.x . 38698693 .
3. Xu F, Lin-Chao S, Cohen SN . The Escherichia coli pcnB gene promotes adenylylation of antisense RNAI of ColE1-type plasmids in vivo and degradation of RNAI decay intermediates . Proceedings of the National Academy of Sciences of the United States of America . 90 . 14 . 6756–6760 . July 1993 . 7688127 . 47011 . 10.1073/pnas.90.14.6756 . 1993PNAS...90.6756X . free .