FlmB RNA is a family of non-coding RNAs

Non-coding RNA

A non-coding RNA is a functional RNA molecule that is not translated into a protein. Less-frequently used synonyms are non-protein-coding RNA , non-messenger RNA and functional RNA . The term small RNA is often used for short bacterial ncRNAs...

 which form a type-1 toxin antitoxin system

Toxin-antitoxin system

A toxin-antitoxin system is a set of two or more closely linked genes that together encode both a protein 'poison' and a corresponding 'antidote'. When these systems are contained on plasmids – transferable genetic elements – they ensure that only the daughter cells that inherit the plasmid...

 with the protein

Protein

Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...

 toxin FlmA. FlmB RNA transcript is 100 nucleotides

Nucleotide

Nucleotides are molecules that, when joined together, make up the structural units of RNA and DNA. In addition, nucleotides participate in cellular signaling , and are incorporated into important cofactors of enzymatic reactions...

 in length and is homologous to sok RNA from 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...

 and fulfills the identical function as a post-segregational killing (PSK) mechanism.

flmB is found on the F-plasmid of Escherichia coli

Escherichia coli

Escherichia coli is a Gram-negative, rod-shaped bacterium that is commonly found in the lower intestine of warm-blooded organisms . Most E. coli strains are harmless, but some serotypes can cause serious food poisoning in humans, and are occasionally responsible for product recalls...

and Salmonella enterica

Salmonella enterica

Salmonella enterica is a rod-shaped flagellated, facultative anaerobic, Gram-negative bacterium, and a member of the genus Salmonella.- Epidemiology :...

. It is responsible for stabilising the plasmid. If the plasmid is not inherited

Mendelian inheritance

Mendelian inheritance is a scientific description of how hereditary characteristics are passed from parent organisms to their offspring; it underlies much of genetics...

, long-lived FlmA mRNA and protein will be highly toxic to the cell, possibly to the point of causing cell death

Programmed cell death

Programmed cell-death is death of a cell in any form, mediated by an intracellular program. PCD is carried out in a regulated process which generally confers advantage during an organism's life-cycle...

. Daughter cells which inherit the 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...

 inherit the FlmB gene

Gene

A gene is a molecular unit of heredity of a living organism. It is a name given to some stretches of DNA and RNA that code for a type of protein or for an RNA chain that has a function in the organism. Living beings depend on genes, as they specify all proteins and functional RNA chains...

, coding for FlmB RNA which binds the leader sequence

Five prime untranslated region

A messenger ribonucleic acid molecule codes for a protein through translation. The mRNA also contains regions that are not translated: in eukaryotes these include the 5' untranslated region, 3' untranslated region, 5' cap and poly-A tail....

 of FlmA mRNA and represses its translation

Translation (genetics)

In molecular biology and genetics, translation is the third stage of protein biosynthesis . In translation, messenger RNA produced by transcription is decoded by the ribosome to produce a specific amino acid chain, or polypeptide, that will later fold into an active protein...

.

See also

• Toxin-antitoxin system
  Toxin-antitoxin system
  A toxin-antitoxin system is a set of two or more closely linked genes that together encode both a protein 'poison' and a corresponding 'antidote'. When these systems are contained on plasmids – transferable genetic elements – they ensure that only the daughter cells that inherit the plasmid...
  
  
• IstR RNA
  IstR RNA
  The TisB-IstR toxin-antitoxin system is the first known toxin-antitoxin system which is induced by the SOS response in response to DNA damage.-IstR-1 and IstR-2:...
  
  
• RdlD RNA
  RdlD RNA
  RdlD RNA is a family of small non-coding RNAs which repress the protein LdrD in a type I toxin-antitoxin system. It was discovered in Escherichia coli strain K-12 in a long direct repeat named LDR-D. This locus encodes two products: a 35 amino acid peptide toxin and a 60 nucleotide RNA antitoxin...
  
  
• Sib RNA
• SymR RNA
  SymR RNA
  SymR RNA is a non-coding RNA which forms a type I toxin-antitoxin system along with the protein SymE. SymR was originally labelled RyjC and is a 77nt RNA with a σ70 promoter. RyjC was found to overlap the yjiW open reading frame on the opposite strand by 6nt, and was characterised as an antisense...
  
  
• ptaRNA1