Rsa RNA

RsaA

Represses the translation of the transcriptional regulator MgrA by binding to its mRNA, enhances biofilm formation and decreases bacterial virulence. Other mRNAs: including SsaA-like enzymes involved in peptidoglycan metabolism and the secreted anti-inflammatory FLIPr protein were validated as direct targets of RsaA.

RsaE

RsaE is found in other members of the genus Staphylococcus such as Staphylococcus epidermidis and Staphylococcus saprophyticus and is the only Rsa RNA to be found outside of this genus, in Macrococcus caseolyticus and Bacillus. In Bacillus subtilis, RsaE had previously been identified as ncr22. RsaE is also consistently found downstream of PepF which codes for oligoendopeptidase F. The function of RsaE was discovered using gene knockout analysis and gene overexpression - it was found to regulate the expression of several enzymes involved in metabolism via antisense binding of their mRNA.

RsaE was shown to be regulated by the presence of nitric oxide (NO). In Bacillus subtilis it controls expression of genes with functions related to oxidative stress and oxidation-reduction reactions and it was renamed RoxS (for related to oxidative stress).

RsaF

In S.aureus species RsaF is located in the same intergenic region as RsaE and overlaps with 3′ end of RsaE by approximately 20bp. In contrast to RsaE, RsaF and its upstream gene have only been identified in S.aureus species.

RsaK

RsaK is found in the leader sequence of glcA mRNA which encodes an enzyme involved in the glucose-specific phosphotransferase system. RsaK also contains a conserved ribonucleic antiterminator system, as recognised by GclT protein.

RsaI

RsaOG also renamed RsaI is thought to fine-tune the regulation of toxin or invasion mechanisms in S. aureus via trans-acting mechanisms. Its secondary structure contains a pseudoknot formed between two highly conserved unpaired sequences.

Expression patterns

RsaD, E H and I were found to be highly expressed in S. aureus. Expression levels of other Rsa RNAs varied under various environmental conditions, for example RsaC was induced by cold shock and RsaA is induced in response to osmotic stress.

RsaE and RsaF genes overlap in S.aureus species but appear to have opposite expression patterns. Transcriptional interference due to an overlap between a σA recognition motif and a potential σB binding site is proposed as a mechanism causing the differential expression of the two transcripts

References

References

1. (November 2009). "A search for small noncoding RNAs in Staphylococcus aureus reveals a conserved sequence motif for regulation". Nucleic Acids Research.
2. (June 2009). "Single-pass classification of all noncoding sequences in a bacterial genome using phylogenetic profiles". Genome Research.
3. (October 2010). "Experimental discovery of small RNAs in Staphylococcus aureus reveals a riboregulator of central metabolism". Nucleic Acids Research.
4. (March 2014). "A non-coding RNA promotes bacterial persistence and decreases virulence by regulating a regulator in Staphylococcus aureus". PLOS Pathogens.
5. (June 2017). "The RNA targetome of Staphylococcus aureus non-coding RNA RsaA: impact on cell surface properties and defense mechanisms". Nucleic Acids Research.
6. (March 2010). "RsaOG, a new staphylococcal family of highly transcribed non-coding RNA". RNA Biology.
7. (August 2009). "VARNA: Interactive drawing and editing of the RNA secondary structure". Bioinformatics.
8. (September 2009). "The transcriptionally active regions in the genome of Bacillus subtilis". Molecular Microbiology.
9. (October 2010). "Identification of regulatory RNAs in Bacillus subtilis". Nucleic Acids Research.
10. (September 2018). "The conserved regulatory RNA RsaE down-regulates the arginine degradation pathway in Staphylococcus aureus". Nucleic Acids Research.
11. (February 2015). "A nitric oxide regulated small RNA controls expression of genes involved in redox homeostasis in Bacillus subtilis". PLOS Genetics.
12. (November 1999). "Specific interaction of the RNA-binding domain of the bacillus subtilis transcriptional antiterminator GlcT with its RNA target, RAT". Journal of Molecular Biology.
13. (June 2005). "Transcriptional interference—a crash course". Trends in Genetics.