MicX sRNA explained

MicX Vibrio cholerae sRNA
Symbol:	MicX
Rfam:	RF01808
Rna Type:	sRNA
Tax Domain:	Vibrio cholerae

MicX sRNA (formerly known as A10)^[1] is a small non-coding RNA found in Vibrio cholerae.^[2] It was given the name MicX as it has a similar function to MicA, MicC and MicF in E. coli.^[3] MicX sRNA negatively regulates an outer membrane protein (coded for by VC0972) and also a component of an ABC transporter (gene VC0620).^[4] These interactions were predicted and then confirmed using a DNA microarray.

MicX was identified through a bioinformatics screen of V. cholerae having been previously predicted. Levels of transcription of this sRNA were compared under several conditions: it was found to be expressed on all tested mediums; richer mediums slightly reduced transcription; repression of certain sigma factors (δ^S and δ^E) did not change transcription but it was dramatically reduced in the absence of Hfq protein. This observation is in accordance with other sRNA expression patterns.^{[5] [6]}

The MicX RNA gene overlaps with VCA0943 - a gene coding for a maltose transporter permease - but the ribonuclease RNAase E processes the MicX transcript to create an active and stable form containing only the VCA0943 3′ UTR.

See also

• Hfq protein

Further reading

• Gottesman S . The small RNA regulators of Escherichia coli: roles and mechanisms* . Annual Review of Microbiology . 58 . 303–328 . 2004 . 15487940 . 10.1146/annurev.micro.58.030603.123841 .
• Schlüter JP, Reinkensmeier J, Daschkey S, Evguenieva-Hackenberg E, Janssen S, Jänicke S, Becker JD, Giegerich R, Becker A . A genome-wide survey of sRNAs in the symbiotic nitrogen-fixing alpha-proteobacterium Sinorhizobium meliloti . BMC Genomics . 11 . 245 . April 2010 . 20398411 . 2873474 . 10.1186/1471-2164-11-245 . free .
• Sittka A, Sharma CM, Rolle K, Vogel J . Deep sequencing of Salmonella RNA associated with heterologous Hfq proteins in vivo reveals small RNAs as a major target class and identifies RNA processing phenotypes . RNA Biology . 6 . 3 . 266–275 . July 2009 . 19333007 . 10.4161/rna.6.3.8332 . free .

Notes and References

1. Livny J, Fogel MA, Davis BM, Waldor MK . sRNAPredict: an integrative computational approach to identify sRNAs in bacterial genomes . Nucleic Acids Research . 33 . 13 . 4096–4105 . 2005 . 16049021 . 1180744 . 10.1093/nar/gki715 .
2. Davis BM, Waldor MK . RNase E-dependent processing stabilizes MicX, a Vibrio cholerae sRNA . Molecular Microbiology . 65 . 2 . 373–385 . July 2007 . 17590231 . 1976385 . 10.1111/j.1365-2958.2007.05796.x .
3. Mizuno T, Chou MY, Inouye M . A unique mechanism regulating gene expression: translational inhibition by a complementary RNA transcript (micRNA) . Proceedings of the National Academy of Sciences of the United States of America . 81 . 7 . 1966–1970 . April 1984 . 6201848 . 345417 . 10.1073/pnas.81.7.1966 . 1984PNAS...81.1966M . free .
4. Song T, Mika F, Lindmark B, Liu Z, Schild S, Bishop A, Zhu J, Camilli A, Johansson J, Vogel J, Wai SN . A new Vibrio cholerae sRNA modulates colonization and affects release of outer membrane vesicles . Molecular Microbiology . 70 . 1 . 100–111 . October 2008 . 18681937 . 2628432 . 10.1111/j.1365-2958.2008.06392.x .
5. Sledjeski DD, Whitman C, Zhang A . Hfq is necessary for regulation by the untranslated RNA DsrA . Journal of Bacteriology . 183 . 6 . 1997–2005 . March 2001 . 11222598 . 95095 . 10.1128/JB.183.6.1997-2005.2001 .
6. Massé E, Escorcia FE, Gottesman S . Coupled degradation of a small regulatory RNA and its mRNA targets in Escherichia coli . Genes & Development . 17 . 19 . 2374–2383 . October 2003 . 12975324 . 218075 . 10.1101/gad.1127103 .