Analysis of Small RNA Species: Phylogenetic Trends
S. K. Dutta in DNA Systematics, 2019
A small stable 10S RNA has been identified and characterized from E. coli.121 Ribonuclease P, unique among all the RNA processing enzymes, contains an RNA moiety that is required for its function.122,123 Two RNAs are present in this enzyme. One of them, termed M2, is identical or similar to 10S RNA from E. coli. Also, ribonuclease P from yeast and Bacillus subtilis contains both protein and RNA components.124 Using a cloned segment of DNA for complementation it has been shown that it codes for an RNA species of 340 bases. Sequence analysis of RNA indicates that this RNA is highly G + C rich.125 It originates from DNA. It would be interesting to determine if GC rich 5.5S RNA from Alcaligenes faecalis originates from 10S RNA bound to RNAse.
Cascade Regulation a Model of Integrative Control of Gene Expression in Eukaryotic Cells and Organisms
M. Gerald, M.D. Kolodny in Eukaryotic Gene Regulation, 2018
Another particularly interesting example for this discussion can be found in the most surprising case of the ribonuclease P which is involved in producing functional tRNA from its precursor by splicing.53 This enzyme is a true ribonucleoprotein complex including more than 75% of RNA: its sequence of 350 nucleotides is a genuine constituent, as is rRNA in ribosomes. As in the case of ribosomal RNA, this RNA might provide a double function in serving as an architectural element organizing the protein components on one hand, and on the other, may confer specificity by sequence recognition of the substrate RNA. It has been pointed out that the classical snRNAs are of a sequence complexity that might suffice for standard service functions but not for a role as discriminating regulatory agents. There exists, however, a whole battery of slightly larger nuclear RNA molecules in the molecular weight range of the RNase P RNA which is as yet hardly exploited experimentally.54 A possible generalization of the RNase P mechanism in splicing is thus conceivable and experimentally testable.
Recent Advances in Repositioning Non-Antibiotics against Tuberculosis and other Neglected Tropical Diseases
Venkatesan Jayaprakash, Daniele Castagnolo, Yusuf Özkay in Medicinal Chemistry of Neglected and Tropical Diseases, 2019
Biological targets and/or mode of action: Phenothiazines interfere with multiple metabolic pathways that are crucial for the survival and persistence of pathogenic microorganisms (Varga et al. 2017). They show inhibitory effects on calcium-dependent enzyme systems including those catalyzing ATP hydrolysis for cellular energy. Moreover, phenothiazines have the propensity to concentrate in macrophages, an attribute that enhances their effects against phagocytosed bacteria. Inhibition of transport processes for Ca2+ or K+ enhances retention of these ions in the cytoplasm of the macrophage which promotes acidification of the phagolysosome thereby activating cidal effects (Amaral and Molnar 2014, Kristiansen et al. 2007, Martins et al. 2008). It is known that overexpression of bacterial efflux pumps confers resistance to xenobiotics including drugs which are extruded from the periplasm or cytoplasm. Phenothiazines are said to supress the activity of these transporter proteins thereby hindering bacterial drug tolerance (Amaral et al. 2004, Kaatz et al. 2003, Kristiansen et al. 2015). Recent studies have indicated that phenothiazines are inhibitors of Mtb type II NADH:menaquinone oxidoreductase, a key enzyme of the respiratory chain that is implicated in Mtb persistence in dormancy (Bald et al. 2017, Teh et al. 2007, Warman et al. 2013, Yano et al. 2006). Another study revealed that phenothiazines inhibit Mtb RNase P RNA, an endoribonuclease involved in RNA cleavage (Wu et al. 2016). Others showed that thioridazine modifies the cell envelope permeability of Mtb which has implications for drug uptake (de Keijzer et al. 2016).
The discovery and development of RNA-based therapies for treatment of HIV-1 infection
Published in Expert Opinion on Drug Discovery, 2023
Michelle J Chen, Anne Gatignol, Robert J. Scarborough
Ribozymes are RNAs that catalyze biochemical reactions. The first ribozyme was identified in self-splicing introns, where the RNA catalyzes both cleavage and ligation reactions that result in the excision of the intron from the transcript [38]. Subsequently, it was shown that RNA is the catalytic moiety in RNase P complexes that cleave pre-transfer (t)RNAs [39] and in ribosomes, where ribosomal RNA is responsible for catalyzing the linkage of amino acids to form proteins [40]. The most diverse group of ribozymes are the small, naturally occurring, self-cleaving ribozymes from which most ribozyme therapies have been derived [29,41]. Although these ribozymes catalyze self-cleavage reactions, they can be easily modified to cleave in trans and designed to target an RNA through complementary base pairing. An advantage of small self-cleaving ribozyme motifs is that they do not require cellular proteins to catalyze target cleavage, limiting their ability to disturb cellular physiology. Examples of trans-cleaving ribozymes based on these motifs are shown in Figure 1.
Virus-associated ribozymes and nano carriers against COVID-19
Published in Artificial Cells, Nanomedicine, and Biotechnology, 2021
Beyza Dönmüş, Sinan Ünal, Fatma Ceren Kirmizitaş, Nelisa Türkoğlu Laçin
Ribonuclease P is a protected endonuclease found in bacteria, eukaryotes and archaea that catalyse maturation by cleavage of the 5′ end of the tRNA [67]. RNase P in all the domains contains protein subunits together [68]. In the absence of the protein component of RNase P in bacteria and some archaea, the RNA component can catalyse tRNA maturation. Additionally, in 2008, Holzmann et al. showed that human mitochondrial RNase P is only a protein enzyme required for RNA catalysis [69]. Archael RNase Ps contain the catalytic core of bacterial RNase P but lack some stabilizing elements [70]. Figure 2 shows the Escherichia coli RNase P complex.
Periodontal tissues are targets for Sars-Cov-2: a post-mortem study
Published in Journal of Oral Microbiology, 2021
Bruno Fernandes Matuck, Marisa Dolhnikoff, Gilvan V. A. Maia, Daniel Isaac Sendyk, Amanda Zarpellon, Sara Costa Gomes, Amaro Nunes Duarte-Neto, João Renato Rebello Pinho, Michele Soares Gomes-Gouvêa, Suzana C.O. M. Sousa, Thais Mauad, Paulo Hilário do Nascimento Saldiva, Paulo H. Braz-Silva, Luiz Fernando Ferraz da Silva
Tissue samples were fixed in buffered 10% formalin, embedded in paraffin and 3 µm sections were stained with hematoxylin and eosin (H&E). Samples measuring 0.5 cm3 were stored at −80°C. Tissue samples were macerated, and nucleic acid extraction was performed using the TRIzol® reagent (Invitrogen). Molecular detection of SARS-CoV-2 was performed with the use of the SuperScriptTM III PlatinumTM One-Step qRT-PCR Kit (Invitrogen) and primers/probes sets for E, RdRp and N (N1) gene amplification [21,22]. Human RNase P gene was also amplified as a nucleic acid extraction control [22].
Related Knowledge Centers
- Protein
- Ribosome
- Ribozyme
- Rna
- Signal Recognition Particle
- Transfer Rna
- Ribonuclease
- NON-Coding Rna
- 5S Ribosomal Rna
- U6 Spliceosomal Rna