| ryfA RNA | |
|---|---|
 Predicted secondary structure and sequence conservation of ryfA | |
| Identifiers | |
| Symbol | ryfA |
| Rfam | RF00126 |
| Other data | |
| RNA type | Gene; sRNA |
| Domain(s) | Bacteria |
| SO | SO:0000655 |
| PDB structures | PDBe |
The ryfA RNA gene is a non-coding RNA present in E. coli , Shigella flexneri and Salmonella species where it is found between the ydaN and dbpA genes. These RNA genes are about 300 nucleotides in length. The function of this RNA is unknown. [1] [2]
Transfer-messenger RNA is a bacterial RNA molecule with dual tRNA-like and messenger RNA-like properties. The tmRNA forms a ribonucleoprotein complex (tmRNP) together with Small Protein B (SmpB), Elongation Factor Tu (EF-Tu), and ribosomal protein S1. In trans-translation, tmRNA and its associated proteins bind to bacterial ribosomes which have stalled in the middle of protein biosynthesis, for example when reaching the end of a messenger RNA which has lost its stop codon. The tmRNA is remarkably versatile: it recycles the stalled ribosome, adds a proteolysis-inducing tag to the unfinished polypeptide, and facilitates the degradation of the aberrant messenger RNA. In the majority of bacteria these functions are carried out by standard one-piece tmRNAs. In other bacterial species, a permuted ssrA gene produces a two-piece tmRNA in which two separate RNA chains are joined by base-pairing.
The SraC/RyeA RNA is a non-coding RNA that was discovered in E. coli during two large scale screens for RNAs. The function of this RNA is currently unknown. This RNA overlaps the SdsR/RyeB RNA on the opposite strand suggesting that the two RNAs may act in a concerted manner.
The OmrA-B RNA gene family is a pair of homologous OmpR-regulated small non-coding RNA that was discovered in E. coli during two large-scale screens. OmrA-B is highly abundant in stationary phase, but low levels could be detected in exponentially growing cells as well. RygB is adjacent to RygA a closely related RNA. These RNAs bind to the Hfq protein and regulate gene expression by antisense binding. They negatively regulate the expression of several genes encoding outer membrane proteins, including cirA, CsgD, fecA, fepA and ompT by binding in the vicinity of the Shine-Dalgarno sequence, suggesting the control of these targets is dependent on Hfq protein and RNase E. Taken together, these data suggest that OmrA-B participates in the regulation of outer membrane composition, responding to environmental conditions.
Sib RNA refers to a group of related non-coding RNA. They were originally named QUAD RNA after they were discovered as four repeat elements in Escherichia coli intergenic regions. The family was later renamed Sib when it was discovered that the number of repeats is variable in other species and in other E. coli strains.
The RprA RNA gene encodes a 106 nucleotide regulatory non-coding RNA. Translational regulation of the stationary phase sigma factor RpoS is mediated by the formation of a double-stranded RNA stem-loop structure in the upstream region of the rpoS messenger RNA, occluding the translation initiation site.
RybB is a small non-coding RNA was identified in a large scale screen of Escherichia coli. The function of this short RNA has been studied using a transcriptomic approach and kinetic analyses of target mRNA decay in vivo. RybB was identified as a factor that selectively accelerates the decay of multiple major omp mRNAs upon induction of the envelope stress response. This RNA has been shown to bind to the Hfq protein.
The RydB RNA is a non-coding RNA originally identified in E. coli in an RNA screen. This gene is only 67 nucleotides in length and is composed of a hairpin like structure. RydB lies between the ydiC and ydiH in E. coli. Homologous RNA genes have been found in other species such as Shigella flexneri and Salmonella species. The molecular function of this RNA is unknown.
The SdsR/RyeB RNA is a non-coding RNA that was identified in a large scale screen of E. coli. The exact 5′ and 3′ ends of this RNA are uncertain. This RNA overlaps the SraC/RyeA RNA on the opposite strand suggesting that the two may act in a concerted manner. It is transcribed by general stress factor σs and is most highly expressed in stationary phase. SdsR/RyeB RNA interacts with Hfq.
The CyaR RNA non-coding RNA was identified in a large scale screen of Escherichia coli and was called candidate 14. The exact 5′ and 3′ ends of this RNA are uncertain. This gene lies between yegQ and orgK in E. coli. This small RNA was shown to be bound by the Hfq protein. This RNA has been renamed as CyaR for. It has been shown that the CyaR RNA acts as a repressor of the porin OmpX. It has also been shown that cyaR expression is tightly controlled by the cyclic AMP receptor protein, CRP.
RyhB RNA is a 90 nucleotide RNA that down-regulates a set of iron-storage and iron-using proteins when iron is limiting; it is itself negatively regulated by the ferric uptake repressor protein, Fur.
Spot 42 (spf) RNA is a regulatory non-coding bacterial small RNA encoded by the spf gene. Spf is found in gammaproteobacteria and the majority of experimental work on Spot42 has been performed in Escherichia coli and recently in Aliivibrio salmonicida. In the cell Spot42 plays essential roles as a regulator in carbohydrate metabolism and uptake, and its expression is activated by glucose, and inhibited by the cAMP-CRP complex.
The GlmY RNA family consists of a number of bacterial RNA genes of around 167 bases in length. The GlmY RNA gene is present in Escherichia coli, Shigella flexneri, Yersinia pestis and Salmonella species, where it is found between the yfhK and purL genes. It was originally predicted in a bioinformatic screen for novel ncRNAs in E. coli.
REX2, RNA exonuclease 2 homolog , also known as REXO2, is an enzyme which in humans is encoded by the REXO2 gene.
tRNA-nucleotidyltransferase 1, is an enzyme that in humans is encoded by the TRNT1 gene. This enzyme adds the nucleotide sequence CCA to the 3' end of tRNA, using ATP and CTP as substrates. The sequence creates the binding site for an amino acid.
39S ribosomal protein L24, mitochondrial is a protein that in humans is encoded by the MRPL24 gene.
The Actino-pnp RNA motif is a conserved structure found in Actinomycetota that is apparently in the 5' untranslated regions of genes predicted to encode exoribonucleases. The RNA element's function is likely analogous to an RNA structure found upstream of polynucleotide phosphorylase genes in E. coli and related enterobacteria. In this latter system, the polynucleotide phosphorlyase gene regulates its own expression levels by a feedback mechanism that involves its activity upon the RNA structure. However, the E. coli RNA appears to be structurally unrelated to the Actino-pnp motif.
Bacterial small RNAs (bsRNA) are small RNAs produced by bacteria; they are 50- to 500-nucleotide non-coding RNA molecules, highly structured and containing several stem-loops. Numerous sRNAs have been identified using both computational analysis and laboratory-based techniques such as Northern blotting, microarrays and RNA-Seq in a number of bacterial species including Escherichia coli, the model pathogen Salmonella, the nitrogen-fixing alphaproteobacterium Sinorhizobium meliloti, marine cyanobacteria, Francisella tularensis, Streptococcus pyogenes, the pathogen Staphylococcus aureus, and the plant pathogen Xanthomonas oryzae pathovar oryzae. Bacterial sRNAs affect how genes are expressed within bacterial cells via interaction with mRNA or protein, and thus can affect a variety of bacterial functions like metabolism, virulence, environmental stress response, and structure.
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 dependent on fumarate and nitrate reductase regulator (FNR), a direct oxygen availability sensor.
Escherichia coli contains a number of small RNAs located in intergenic regions of its genome. The presence of at least 55 of these has been verified experimentally. 275 potential sRNA-encoding loci were identified computationally using the QRNA program. These loci will include false positives, so the number of sRNA genes in E. coli is likely to be less than 275. A computational screen based on promoter sequences recognised by the sigma factor sigma 70 and on Rho-independent terminators predicted 24 putative sRNA genes, 14 of these were verified experimentally by northern blotting. The experimentally verified sRNAs included the well characterised sRNAs RprA and RyhB. Many of the sRNAs identified in this screen, including RprA, RyhB, SraB and SraL, are only expressed in the stationary phase of bacterial cell growth. A screen for sRNA genes based on homology to Salmonella and Klebsiella identified 59 candidate sRNA genes. From this set of candidate genes, microarray analysis and northern blotting confirmed the existence of 17 previously undescribed sRNAs, many of which bind to the chaperone protein Hfq and regulate the translation of RpoS. UptR sRNA transcribed from the uptR gene is implicated in suppressing extracytoplasmic toxicity by reducing the amount of membrane-bound toxic hybrid protein.
The SraL RNA, also known as RyjA, is a small non-coding RNA discovered in E. coli, and later in Salmonella Tiphimurium. This ncRNA was found to be expressed only in stationary phase. It may possibly play a role in Salmonella virulence. The major stationary phase regulator RpoS is transcriptionally regulating SraL and directly binds to the sraL gene promoter. SraL down-regulates the expression of the ribosome-associated chaperone Trigger Factor (TF), which is involved in the folding of the newly synthesised cystolic proteins.
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