View source for Vibrio regulatory RNA of OmpA

{{Infobox rfam
| Name = Vibrio regulatory RNA of OmpA
| image = VrrA_secondary_structure.jpg
| width = 276px
| caption = A representation of the VrrA [[Nucleic acid secondary structure|secondary structure]] including a colour scheme that indicates the degree of sequence conservation.
| Symbol = VrrA
| AltSymbols =
| Rfam = RF00024
| RNA_type = [[Gene]] [[Antisense RNA]]
| Tax_domain = [[Bacteria]]
| CAS_number =
| EntrezGene =
| HGNCid =
| OMIM =
| PDB =
| RefSeq =
| Chromosome =
| Arm =
| Band =
| LocusSupplementaryData =
}}
'''VrrA''' ('''Vibrio regulatory RNA of OmpA''') is a [[non-coding RNA]] that is conserved across all ''[[Vibrio]]'' species of [[bacteria]] and acts as a repressor for the synthesis of the outer membrane protein [[OmpA-like transmembrane domain|OmpA]]. This non-coding RNA was initially identified from Tn5 [[transposon]] mutant libraries of ''[[Vibrio cholerae]]'' and its location within the bacterial [[genome]] was mapped to the [[intergenic]] region between genes VC1741 and VC1743 by [[Rapid Amplification of cDNA Ends|RACE]] analysis.<ref name="pmid19411843">{{cite journal |vauthors=Song T, Wai SN |title=A novel sRNA that modulates virulence and environmental fitness of Vibrio cholerae |journal=RNA Biol |volume=6 |issue=3 |pages= 254–258|date=July 2009 |pmid=19411843 |doi= 10.4161/rna.6.3.8371|doi-access=free }}</ref>
[[Outer membrane vesicles]] are secreted from the surface of [[gram-negative bacteria]], where they are thought to aid in [[virulence]]. Little is known about how these vesicles aid virulence but it has been speculated that they may contribute by secreting toxins and help in the evasion of the [[immune system]].<ref name="pmid10223967">{{cite journal |vauthors=Kolling GL, Matthews KR |title=Export of virulence genes and Shiga toxin by membrane vesicles of Escherichia coli O157:H7 |journal=Appl. Environ. Microbiol. |volume=65 |issue=5 |pages=1843–1848 |date=May 1999 |pmid=10223967 |pmc=91264 }}</ref><ref name="pmid9864204">{{cite journal |vauthors=Saunders NB, Shoemaker DR, Brandt BL, Moran EE, Larsen T, Zollinger WD |title=Immunogenicity of intranasally administered meningococcal native outer membrane vesicles in mice |journal=Infect. Immun. |volume=67 |issue=1 |pages=113–119 |date=January 1999 |pmid=9864204 |pmc=96285 }}</ref><ref name="pmid16552031">{{cite journal |vauthors=Kouokam JC, Wai SN, Fällman M, Dobrindt U, Hacker J, Uhlin BE |title=Active cytotoxic necrotizing factor 1 associated with outer membrane vesicles from uropathogenic Escherichia coli |journal=Infect. Immun. |volume=74 |issue=4 |pages=2022–2030 |date=April 2006 |pmid=16552031 |pmc=1418910 |doi=10.1128/IAI.74.4.2022-2030.2006 }}</ref>
Recent studies showed that VrrA expression is activated by the alternative stress [[sigma factor]], sigma E; unlike other strains of bacteria such as ''[[Escherichia coli|E. coli]]'' and ''[[Salmonella]]'', it does not require the [[Hfq]] protein to regulate the sigma factor. It was also shown that VrrA [[Transcription (genetics)|transcription]] increases on exposure to [[UV light]] and that over expression of VrrA resulted in an increase in outer membrane vesicles secreted. From these studies it has been suggested that VrrA acts to relieve outer membrane stress by limiting the synthesis of OmpA protein and that outer membrane vesicles provide the bacteria physical protect against UV light.<ref name="pmid19411843" />
==References==
{{reflist}}
==External links==
* {{Rfam|id=RF01456 |name=Vibrio regulatory RNA of OmpA}}
[[Category:Non-coding RNA]]
{{molecular-biology-stub}}