FnrS RNA
Encyclopedia
FnrS RNA is a family of Hfq
-binding small RNA
whose expression
is upregulated in response to anaerobic
conditions. It is named FnrS because its expression is strongly dependant on fumarate
and nitrate reductase
regulator (FNR), a direct oxygen
availability sensor.
A conserved intergenic region between genes ydaN and dbpA was predicted to encode an sRNA, adjacent to where another non-coding RNA
(C0343
) has been identified. However, northern blot
analysis of this 477bp
sequence yielded no results. A subsequent tiling array
analysis sequencing Hfq-binding sRNA found that the Watson strand did indeed encode an sRNA.
. The majority of genes downregulated by FnrS are required for aerobic metabolism or the oxidative stress
response. Some of the genes downregulated by FrnS are:
There is evidence to suggest that the expression of FnrS is regulated by the RcsCDB signalling system in Salmonella enterica
.
Hfq protein
The Hfq protein encoded by the hfq gene was discovered in 1968 as an Escherichia. coli host factor that was essential for replication of the bacteriophage Qβ. It is now clear that Hfq is an abundant bacterial RNA binding protein which has many important physiological roles. Usually mediated by...
-binding small RNA
RNA
Ribonucleic acid , or RNA, is one of the three major macromolecules that are essential for all known forms of life....
whose expression
Gene expression
Gene expression is the process by which information from a gene is used in the synthesis of a functional gene product. These products are often proteins, but in non-protein coding genes such as ribosomal RNA , transfer RNA or small nuclear RNA genes, the product is a functional RNA...
is upregulated in response to anaerobic
Anaerobic organism
An anaerobic organism or anaerobe is any organism that does not require oxygen for growth. It could possibly react negatively and may even die if oxygen is present...
conditions. It is named FnrS because its expression is strongly dependant on fumarate
Fumarate reductase
Fumarate reductase is the enzyme that converts fumarate to succinate, and is important in microbial metabolism as a part of anaerobic respiration.Succinate + acceptor fumarate + reduced acceptor...
and nitrate reductase
Nitrate reductase
Nitrate reductases are molybdoenzymes that reduce nitrate to nitrite .* Eukaryotic nitrate reductases are part of the sulfite oxidase family of molybdoenzymes....
regulator (FNR), a direct oxygen
Oxygen
Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...
availability sensor.
A conserved intergenic region between genes ydaN and dbpA was predicted to encode an sRNA, adjacent to where another non-coding RNA
Non-coding RNA
A non-coding RNA is a functional RNA molecule that is not translated into a protein. Less-frequently used synonyms are non-protein-coding RNA , non-messenger RNA and functional RNA . The term small RNA is often used for short bacterial ncRNAs...
(C0343
C0343 RNA
The C0343 RNA is a bacterial non-coding RNA of 74 nucleotides in length that is found between the ydaN and dbpA genes in the genomes of Escherichia coli and Shigella flexneri , Salmonella enterica and Salmonella typhimurium. This ncRNA was originally identified in E.coli using high-density...
) has been identified. However, northern blot
Northern blot
The northern blot is a technique used in molecular biology research to study gene expression by detection of RNA in a sample. With northern blotting it is possible to observe cellular control over structure and function by determining the particular gene expression levels during differentiation,...
analysis of this 477bp
Nucleotide
Nucleotides are molecules that, when joined together, make up the structural units of RNA and DNA. In addition, nucleotides participate in cellular signaling , and are incorporated into important cofactors of enzymatic reactions...
sequence yielded no results. A subsequent tiling array
Tiling array
Tiling Arrays are a subtype of microarray chips. Like traditional microarrays, they function by hybridizing labeled DNA or RNA target molecules to probes fixed onto a solid surface. Tiling arrays differ from traditional microarrays in the nature of the probes...
analysis sequencing Hfq-binding sRNA found that the Watson strand did indeed encode an sRNA.
Gene regulation
FnrS has been shown to downregulate 32 different mRNAs in Enterobacteria, in 15 of these cases it does so by base-pairing with the mRNA transcriptTranscription (genetics)
Transcription is the process of creating a complementary RNA copy of a sequence of DNA. Both RNA and DNA are nucleic acids, which use base pairs of nucleotides as a complementary language that can be converted back and forth from DNA to RNA by the action of the correct enzymes...
. The majority of genes downregulated by FnrS are required for aerobic metabolism or the oxidative stress
Oxidative stress
Oxidative stress represents an imbalance between the production and manifestation of reactive oxygen species and a biological system's ability to readily detoxify the reactive intermediates or to repair the resulting damage...
response. Some of the genes downregulated by FrnS are:
- adhP - an alcohol dehydrogenaseAlcohol dehydrogenaseAlcohol dehydrogenases are a group of dehydrogenase enzymes that occur in many organisms and facilitate the interconversion between alcohols and aldehydes or ketones with the reduction of nicotinamide adenine dinucleotide...
involved in metabolism - cydD - zinc sensitive ATPAdenosine triphosphateAdenosine-5'-triphosphate is a multifunctional nucleoside triphosphate used in cells as a coenzyme. It is often called the "molecular unit of currency" of intracellular energy transfer. ATP transports chemical energy within cells for metabolism...
-binding component of cytochromeCytochromeCytochromes are, in general, membrane-bound hemoproteins that contain heme groups and carry out electron transport.They are found either as monomeric proteins or as subunits of bigger enzymatic complexes that catalyze redox reactions....
-related transport - mqo - membrane associated malate:quinone oxidoreductase which operates in the citric acid cycleCitric acid cycleThe citric acid cycle — also known as the tricarboxylic acid cycle , the Krebs cycle, or the Szent-Györgyi-Krebs cycle — is a series of chemical reactions which is used by all aerobic living organisms to generate energy through the oxidization of acetate derived from carbohydrates, fats and...
- sodB/A - a superoxide dismutase which aids with oxygen stress resistance
- ygiW - a hypothetical outer membraneOuter membraneThe bacterial outer membrane is found in Gram-negative bacteria. Its composition is distinct from that of the cytoplasmic membrane - among other things, the outer leaflet of the membrane includes a complex lipopolysaccharide whose lipid portion acts as an endotoxin - and it is linked to the cell's...
protein
There is evidence to suggest that the expression of FnrS is regulated by the RcsCDB signalling system in Salmonella enterica
Salmonella enterica
Salmonella enterica is a rod-shaped flagellated, facultative anaerobic, Gram-negative bacterium, and a member of the genus Salmonella.- Epidemiology :...
.