FlmA-FlmB toxin-antitoxin system

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flmB
Flmb SScons.png
Conserved secondary structure of flmB RNA.
Identifiers
SymbolFlmB
Other data
RNA type antisense RNA
Domain(s) E. coli, S. enterica
PDB structures PDBe

The FlmA-FlmB toxin-antitoxin system consists of FlmB RNA (F leading-region maintenance B), a family of non-coding RNAs and the protein toxin FlmA. The FlmB RNA transcript is 100 nucleotides in length and is homologous to sok RNA from the hok/sok system and fulfills the identical function as a post-segregational killing (PSK) mechanism. [1] [2]

Contents

flmB is found on the F-plasmid of Escherichia coli and Salmonella enterica . It is responsible for stabilising the plasmid. If the plasmid is not inherited, long-lived FlmA mRNA and protein will be highly toxic to the cell, possibly to the point of causing cell death. [2] Daughter cells which inherit the plasmid inherit the FlmB gene, coding for FlmB RNA which binds the leader sequence of FlmA mRNA and represses its translation. [1]

See also

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<i>Escherichia coli</i> sRNA

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The SrnB-SrnC toxin-antitoxin system of the F plasmid is homologous to the hok/sok system of R1. Like the hok/sok system, it performs a post-segregational killing function, ensuring that all surviving daughter cells inherit the F plasmid. The system consists of srnB' mRNA which is relatively stable and codes for the toxic protein SrnB, srnB mRNA, a regulatory element and srnC mRNA, an antitoxin with complementarity to srnB.

CcdA/CcdB Type II Toxin-antitoxin system

The CcdA/CcdB Type II Toxin-antitoxin system is one example of the bacterial toxin-antitoxin (TA) systems that encode two proteins, one a potent inhibitor of cell proliferation (toxin) and the other its specific antidote (antitoxin). These systems preferentially guarantee growth of plasmid-carrying daughter cells in a bacterial population by killing newborn bacteria that have not inherited a plasmid copy at cell division.

ParDE type II toxin-antitoxin system

The parDE type II toxin-antitoxin system is one example of the bacterial toxin-antitoxin (TA) systems that encode two proteins, one a potent inhibitor of cell proliferation (toxin) and the other its specific antidote (antitoxin). These systems preferentially guarantee growth of plasmid-carrying daughter cells in a bacterial population by killing newborn bacteria that have not inherited a plasmid copy at cell division.

References

  1. 1 2 Loh SM, Cram DS, Skurray RA (June 1988). "Nucleotide sequence and transcriptional analysis of a third function (Flm) involved in F-plasmid maintenance". Gene. 66 (2): 259–268. doi:10.1016/0378-1119(88)90362-9. PMID   3049248.
  2. 1 2 Kobayashi M, Kurusu Y, Yukawa H (February 1991). "High-expression of a target gene and high-stability of the plasmid". Appl. Biochem. Biotechnol. 27 (2): 145–162. doi:10.1007/BF02921523. PMID   2029184.

Further reading