R1 plasmid
Encyclopedia
The R1 Plasmid is a plasmid
Plasmid
In microbiology and genetics, a plasmid is a DNA molecule that is separate from, and can replicate independently of, the chromosomal DNA. They are double-stranded and, in many cases, circular...

 that was first isolated from Salmonella paratyphi bacteria
Bacteria
Bacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...

 in 1963.

The R1 plasmid imparts multi-drug antibiotic resistance
Antibiotic resistance
Antibiotic resistance is a type of drug resistance where a microorganism is able to survive exposure to an antibiotic. While a spontaneous or induced genetic mutation in bacteria may confer resistance to antimicrobial drugs, genes that confer resistance can be transferred between bacteria in a...

 to its host bacteria.

It’s known as a “low copy” plasmid, meaning that it exists in relatively few copies in any given bacteria. Because of its low copy nature, R1 must rely on “type II” segregation system to ensure that at least one copy is contained in each daughter cell after mitosis
Mitosis
Mitosis is the process by which a eukaryotic cell separates the chromosomes in its cell nucleus into two identical sets, in two separate nuclei. It is generally followed immediately by cytokinesis, which divides the nuclei, cytoplasm, organelles and cell membrane into two cells containing roughly...

.

Some genes on the R1 plasmid are:
  • ParM
    ParM
    ParM is a prokaryotic actin homologue which provides the force to drive copies of the R1 plasmid to opposite ends of rod shaped bacteria before mitosis....

     is a prokaryotic actin homologue which provides the force to drive copies of the R1 plasmid to opposite ends of rod shaped bacteria before mitosis.
  • The Hok/sok system
    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...

     a postsegregational killing system of the plasmid.
  • CopA-like RNA
    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 long hairpin structure interrupted by several unpaired...

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