SprD

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SprD
SprD SScons.png
Conserved secondary structure of SprD.
Identifiers
SymbolSprD
Rfam RF01828
Other data
RNA typeGene
Domain(s) Staphylococcus aureus
PDB structures PDBe

In molecular biology SprD (Small pathogenicity island RNA D) is a non-coding RNA expressed on pathogenicity islands in Staphylococcus aureus . [1] It was identified in silico along with a number of other sRNAs (SprA-G) through microarray analysis which were confirmed using a Northern blot. [2] SprD has been found to significantly contribute to causing disease in an animal model. [1]

Contents

Function

SprD is located between genes scn and chp in the innate immune evasion cluster (IEC) of the S. aureus genome. Its placement within this region was the first indication of a virulence-factor regulatory function. [1]

SprD binds with sbi (Staphylococcus aureus binder of IgG) [3] mRNA which encodes an immune evasion protein. It occludes the Shine-Dalgarno sequence and the initiation codon of sbi, forming a sbi mRNA-SprD duplex repressing the translation of the mRNA. [1]

sbi protein interferes with the host's innate immune response by binding Factor H, Complement component 3 and IgG. [3] [4]

See also

Related Research Articles

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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 positive for catalase and nitrate reduction and is a facultative anaerobe that can grow without the need for oxygen. Although S. aureus usually acts as a commensal of the human microbiota, it can also become an opportunistic pathogen, being a common cause of skin infections including abscesses, respiratory infections such as sinusitis, and food poisoning. Pathogenic strains often promote infections by producing virulence factors such as potent protein toxins, and the expression of a cell-surface protein that binds and inactivates antibodies. S. aureus is one of the leading pathogens for deaths associated with antimicrobial resistance and the emergence of antibiotic-resistant strains, such as methicillin-resistant S. aureus (MRSA), is a worldwide problem in clinical medicine. Despite much research and development, no vaccine for S. aureus has been approved.

Pathogenicity islands (PAIs), as termed in 1990, are a distinct class of genomic islands acquired by microorganisms through horizontal gene transfer. Pathogenicity islands are found in both animal and plant pathogens. Additionally, PAIs are found in both gram-positive and gram-negative bacteria. They are transferred through horizontal gene transfer events such as transfer by a plasmid, phage, or conjugative transposon. Therefore, PAIs contribute to microorganisms' ability to evolve.

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<span class="mw-page-title-main">Protein A</span>

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<span class="mw-page-title-main">Hemolysin</span> Molecule destroying the membrane of red blood cells

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RNAIII is a stable 514 nt regulatory RNA transcribed by the P3 promoter of the Staphylococcus aureus quorum-sensing agr system ). It is the major effector of the agr regulon, 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 peptide (Hld). RNAIII contains many stem loops, most of which match the Shine-Dalgarno sequence involved in translation 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 (Hla), whose translation RNAIII activates by preventing the formation of an inhibitory foldback loop in the hla mRNA leader.

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<span class="mw-page-title-main">SpAB protein domain</span>

In molecular biology, the domain B, refers to the immunoglobulin-binding domain found in the Staphylococcus aureus virulence factor protein A (SpA). Hence, it is abbreviated to SpAB.

<span class="mw-page-title-main">Glutamyl endopeptidase GluV8</span>

Glutamyl endopeptidase is an extracellular bacterial serine protease of the glutamyl endopeptidase I family that was initially isolated from the Staphylococcus aureus strain V8. The protease is, hence, commonly referred to as "V8 protease", or alternatively SspA from its corresponding gene.

<span class="mw-page-title-main">Aureolysin</span>

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<span class="mw-page-title-main">SprX small RNA</span>

In molecular biology the small pathogenicity island RNA X gene is a bacterial non-coding RNA. It was discovered in a large-scale analysis of Staphylococcus aureus. SprX was shown to influence antibiotic resistance of the bacteria to Vancomycin and Teicoplanin glycopeptides, which are used to treat MRSA infections. In this study the authors identified a SprX target, stage V sporulation protein G. By reducing Spo VG expression levels, SprX affects S. aureus resistance to the glycopeptide antibiotics. Further work demonstrated its involvement in the regulation of pathogenicity factors.

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<span class="mw-page-title-main">Neisseria RNA thermometer</span>

RNA thermometers (RNATs) regulate gene expression in response to temperature, allowing pathogens such as Neisseria meningitidis to switch on silent genes after entering the host organism. However the temperature for expression of Neisseria virulence-associated traits is 42 °C while other bacterial pathogen RNATs require 37 °C. This is probably because N. meningitidis is an obligate commensal of the human nasopharynx and becomes pathogenic during inflammation due to viral infection. Three independent RNA thermosensors were identified in the 5′UTRs of genes needed for: capsule biosynthesis (cssA), the expression of factor H binding protein (fHbp) and sialylation of lipopolysaccharide, which is essential for bacterial resistance against immune killing (lst). The very different nucleotide sequence and predicted inhibitory structures of the three RNATs indicate that they have evolved independently.

The SprA1/SPrA1as toxin/antitoxin system identified in Staphylococcus aureus, belongs to the Type I system encoding toxin protein: SprA1 and antitoxin RNA: SprA1as. The SprA1as postranscriptionally regulates SprA1 encoding small membrane damaging protein PepA1.

Accessory gene regulator (agr) is a complex 5 gene locus that is a global regulator of virulence in Staphylococcus aureus. It encodes a two-component transcriptional quorum-sensing (QS) system activated by an autoinducing, thiolactone-containing cyclic peptide (AIP).

References

  1. 1 2 3 4 Chabelskaya S, Gaillot O, Felden B (June 2010). "A Staphylococcus aureus small RNA is required for bacterial virulence and regulates the expression of an immune-evasion molecule". PLOS Pathog. 6 (6): e1000927. doi: 10.1371/journal.ppat.1000927 . PMC   2880579 . PMID   20532214.
  2. Pichon C, Felden B (October 2005). "Small RNA genes expressed from Staphylococcus aureus genomic and pathogenicity islands with specific expression among pathogenic strains". Proc. Natl. Acad. Sci. U.S.A. 102 (40): 14249–14254. doi: 10.1073/pnas.0503838102 . PMC   1242290 . PMID   16183745.
  3. 1 2 Haupt K, Reuter M, van den Elsen J, et al. (December 2008). "The Staphylococcus aureus protein Sbi acts as a complement inhibitor and forms a tripartite complex with host complement Factor H and C3b". PLOS Pathog. 4 (12): e1000250. doi: 10.1371/journal.ppat.1000250 . PMC   2602735 . PMID   19112495.
  4. Zhang L, Jacobsson K, Vasi J, Lindberg M, Frykberg L (April 1998). "A second IgG-binding protein in Staphylococcus aureus". Microbiology. 144 (4): 985–991. doi: 10.1099/00221287-144-4-985 . PMID   9579072 . Retrieved 2010-08-09.

Further reading