The R1 Plasmid is a plasmid that was first isolated from '' Salmonella paratyphi''

bacteria Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one Cell (biology), biological cell. They constitute a large domain (biology), domain of prokaryotic microorganisms. Typically a few micrometr ...

in 1963. It is a short plasmid, composed of 97,566 nucleotides and 120 genes, that belongs to the IncFII plasmid group.

The R1 plasmid imparts multi-drug antibiotic resistance to its host bacteria. It's known as a "low copy" plasmid, meaning that it exists in relatively few copies in any given bacteria. This characteristic allows the R1 plasmid to have an efficient plasmid stabilization system, that aids in stabilizing medium copy number plasmids. R1 must rely on "Type II" segregation system. This plasmid system ensures that at least one copy is contained in each daughter cell after cell division.

Partitioning System

The R1 plasmid partitioning is a mechanism needed for the inheritance of the R1 plasmid. The par system is composed of the ParR and the parC regions, that interact together. The par system determines the position of the replicon, ensuring that at the end of DNA Replication, the plasmid copies are well-positioned to start cell division. The par system also allows for the initiation of ParM formation. ParM produces two important cytoskeletal proteins, MreB, and actin. ParM is directed to move the plasmid copies to opposite cell poles. Cell division takes place, resulting in the partitioned plasmids in two daughter cells. Some genes on the R1 plasmid are: *

ParM Parm or PARM may refer to: * Parmesan cheese, especially in dishes such as chicken parm * PARM 1 mine, Panzer-Abwehr Richtmine (German, ''Antitank defense arranging mine'') * '' Authentic Party of the Mexican Revolution'', Partido Auténtico de l ...

is a prokaryotic actin homologue which provides the force to drive copies of the R1 plasmid to opposite ends of rod shaped bacteria before division. *The

Hok/sok system The hok/sok system is a postsegregational killing mechanism employed by the R1 plasmid in ''Escherichia coli''. It was the first type I toxin-antitoxin pair to be identified through characterisation of a plasmid-stabilising locus. It is a type I ...

a post-segregational killing system of the plasmid. *

CopA-like RNA CopA-like RNA is a family of non-coding RNAs found on the R1 plasmid. In several groups of bacterial plasmids, antisense RNAs regulate copy number through inhibition of replication initiator protein synthesis. These RNAs are characterised by a ...

, an antisense RNA involved in replication control of the plasmid.

References

{{cell-biology-stub Plasmids