RNAIII is a stable 514 nt regulatory RNA
transcribed by the P3
promoter of the ''
Staphylococcus aureus
''Staphylococcus aureus'' is a Gram-positive spherically shaped bacterium, a member of the Bacillota, and is a usual member of the microbiota of the body, frequently found in the upper respiratory tract and on the skin. It is often posi ...
''
quorum-sensing ''
agr'' system
). It is the major effector of the ''agr''
regulon
In molecular genetics, a regulon is a group of genes that are gene regulation, regulated as a unit, generally controlled by the same regulatory gene that gene expression, expresses a protein acting as a repressor or activator (genetics), activator ...
, which controls the expression of many ''
S. aureus'' genes encoding
exoproteins and cell wall associated proteins plus others encoding regulatory proteins
The RNAIII transcript also encodes the 26 amino acid δ-haemolysin (
S''taphylococcus aureus'' delta toxin) peptide (Hld).
RNAIII contains many stem loops, most of which match the
Shine-Dalgarno sequence involved in
translation
Translation is the communication of the semantics, meaning of a #Source and target languages, source-language text by means of an Dynamic and formal equivalence, equivalent #Source and target languages, target-language text. The English la ...
initiation of the regulated genes.
Some of these interactions are inhibitory, others stimulatory; among the former is the regulatory protein Rot. In vitro, RNAIII is expressed post exponentially, inhibiting translation of the surface proteins, notably protein A, while stimulating that of the exoproteins, many of which are tissue-degrading enzymes or
cytolysins. Among the latter is the important virulence factor, α-hemolysin (or
alpha toxin) (Hla), whose translation RNAIII activates by preventing the formation of an inhibitory foldback loop in the ''hla''
mRNA
In molecular biology, messenger ribonucleic acid (mRNA) is a single-stranded molecule of RNA that corresponds to the genetic sequence of a gene, and is read by a ribosome in the process of Protein biosynthesis, synthesizing a protein.
mRNA is ...
leader.
References
Further reading
*
*
*
*
*
External links
*
Non-coding RNA
{{molecular-cell-biology-stub