The Sxy 5′ UTR element is an
RNA element that controls expression of the sxy gene in ''
H. influenzae
''Haemophilus influenzae'' (formerly called Pfeiffer's bacillus or ''Bacillus influenzae'') is a Gram-negative, non-motile, coccobacillary, facultatively anaerobic, capnophilic pathogenic bacterium of the family Pasteurellaceae. The bacteria ...
''. The sxy gene is a transcription factor (also known as TfoX) that regulates
competence
Competence may refer to:
*Competence (geology), the resistance of a rock against deformation or plastic flow.
*Competence (human resources), a standardized requirement for an individual to properly perform a specific job
*Competence (law), the me ...
which is the ability of bacteria to take up DNA from their environment.
When the sxy gene is deleted the bacterium loses the ability to express genes in the competence regulon. Cameron ''et al.'' recently showed that mutations in the 5′ end of the sxy gene lead to hypercompetance.
They showed that this region formed an RNA secondary structure that occludes the
Shine-Dalgarno sequence. Mutations that interfere with the stability of this secondary structure lead to increased translation of sxy followed by upregulation of the competence regulon.
tfoR RNA
In the fellow
gammaproteobacterium
Gammaproteobacteria is a class of bacteria in the phylum Pseudomonadota (synonym Proteobacteria). It contains about 250 genera, which makes it the most genera-rich taxon of the Prokaryotes. Several medically, ecologically, and scientifically im ...
''
Vibrio cholerae
''Vibrio cholerae'' is a species of Gram-negative, facultative anaerobe and comma-shaped bacteria. The bacteria naturally live in brackish or saltwater where they attach themselves easily to the chitin-containing shells of crabs, shrimps, and oth ...
'', a different RNA regulatory system is used.
Here, a sRNA named 'tfoR' positively regulates expression of the sxy (tfoX) protein.
The RNA element responds to
chitin
Chitin ( C8 H13 O5 N)n ( ) is a long-chain polymer of ''N''-acetylglucosamine, an amide derivative of glucose. Chitin is probably the second most abundant polysaccharide in nature (behind only cellulose); an estimated 1 billion tons of chit ...
, which is an important regulator of competence in ''V. cholera''.
Deletion of tfoR removed all competence for exogenous DNA in ''V. cholera'' ''
in vivo
Studies that are ''in vivo'' (Latin for "within the living"; often not italicized in English) are those in which the effects of various biological entities are tested on whole, living organisms or cells, usually animals, including humans, and ...
''.
secondary structure
Protein secondary structure is the three dimensional conformational isomerism, form of ''local segments'' of proteins. The two most common Protein structure#Secondary structure, secondary structural elements are alpha helix, alpha helices and beta ...
of tfoR sRNA.
References
External links
Rfam entry for sxy 5′ UTR element
{{DEFAULTSORT:Sxy 5' UTR element
Cis-regulatory RNA elements