In molecular biology, the FasX small RNA (fibronectin/fibrinogen-binding/haemolytic-activity/streptokinase-regulator-X) is a non-coding

small RNA Small RNA (sRNA) are polymeric RNA molecules that are less than 200 nucleotides in length, and are usually non-coding RNA, non-coding. RNA silencing is often a function of these molecules, with the most common and well-studied example being RNA int ...

(sRNA) produced by all group A ''

Streptococcus ''Streptococcus'' is a genus of gram-positive spherical bacteria that belongs to the family Streptococcaceae, within the order Lactobacillales (lactic acid bacteria), in the phylum Bacillota. Cell division in streptococci occurs along a sing ...

''. FasX has also been found in species of group D and group G ''

''. FasX regulates expression of secreted

virulence factor Virulence factors (preferably known as pathogenicity factors or effectors in botany) are cellular structures, molecules and regulatory systems that enable microbial pathogens (bacteria, viruses, fungi, and protozoa) to achieve the following: * c ...

streptokinase Streptokinase is a thrombolysis, thrombolytic medication activating plasminogen by nonenzymatic mechanism. As a medication it is used to thrombolysis, break down clots in some cases of myocardial infarction (heart attack), pulmonary embolism, an ...

(SKA), encoded by the ''ska'' gene. FasX

base pairs A base pair (bp) is a fundamental unit of double-stranded nucleic acids consisting of two nucleobases bound to each other by hydrogen bonds. They form the building blocks of the DNA double helix and contribute to the folded structure of both DNA ...

to the 5' end of the ska

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 ...

, increasing the stability of the mRNA, resulting in elevated levels of streptokinase expression. FasX negatively regulates the expression of pili and fibronectin-binding proteins on the

bacterial Bacteria (; : bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among the ...

cell surface. It binds to the 5' untranslated region of genes in the FCT-region in a serotype-specific manner, reducing the stability of and inhibiting

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 ...

of the pilus

biosynthesis Biosynthesis, i.e., chemical synthesis occurring in biological contexts, is a term most often referring to multi-step, enzyme-Catalysis, catalyzed processes where chemical substances absorbed as nutrients (or previously converted through biosynthe ...

operon In genetics, an operon is a functioning unit of DNA containing a cluster of genes under the control of a single promoter. The genes are transcribed together into an mRNA strand and either translated together in the cytoplasm, or undergo splic ...

mRNA by occluding the ribosome-binding site through a simple Watson-Crick base-pairing mechanism.

See also

References

Further reading