FlmA-FlmB toxin-antitoxin system

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]

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

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

• Toxin-antitoxin system
• IstR RNA
• RdlD RNA
• Sib RNA
• SymR RNA
• ptaRNA1