Search results for "trna"
showing 10 items of 63 documents
Cytosine methylation of tRNA-Asp by DNMT2 has a role in translation of proteins containing poly-Asp sequences
2015
AbstractThe Dnmt2 RNA methyltransferase catalyses the methylation of C38 in the anticodon loop of tRNA-Asp, but the molecular role of this methylation is unknown. Here, we report that mouse aspartyl-tRNA synthetase shows a four to fivefold preference for C38-methylated tRNA-Asp. Consistently, a 30% reduced charging level of tRNA-Asp was observed in Dnmt2 knockout (KO) murine embryonic fibroblast cells. Gene expression analysis with fluorescent reporter proteins fused to an N-terminal poly-Asp sequence showed that protein synthesis of poly-Asp-tagged reporter proteins was reduced in Dnmt2 KO cells as well. The same effect was observed with endogenous proteins containing poly-Asp sequences, i…
Mapping and Quantification of tRNA 2′-O-Methylation by RiboMethSeq
2018
Current development of epitranscriptomics field requires efficient experimental protocols for precise mapping and quantification of various modified nucleotides in RNA. Despite important advances in the field during the last 10 years, this task is still extremely laborious and time-consuming, even when high-throughput analytical approaches are employed. Moreover, only a very limited subset of RNA modifications can be detected and only rarely be quantified by these powerful techniques. In the past, we developed and successfully applied alkaline fragmentation-based RiboMethSeq approach for mapping and precise quantification of multiple 2'-O-methylation residues in ribosomal RNA. Here we descr…
tRNA stabilization by modified nucleotides.
2010
Post-transcriptional ribonucleotide modification is a phenomenon best studied in tRNA, where it occurs most frequently and in great chemical diversity. This paper reviews the intrinsic network of modifications in the structural core of the tRNA, which governs structural flexibility and rigidity to fine-tune the molecule to peak performance and to regulate its steady-state level. Structural effects of RNA modifications range from nanometer-scale rearrangements to subtle restrictions of conformational space on the angstrom scale. Structural stabilization resulting from nucleotide modification results in increased thermal stability and translates into protection against unspecific degradation …
Identification of the 3-amino-3-carboxypropyl (acp) transferase enzyme responsible for acp3U formation at position 47 in Escherichia coli tRNAs
2019
AbstracttRNAs from all domains of life contain modified nucleotides. However, even for the experimentally most thoroughly characterized model organism Escherichia coli not all tRNA modification enzymes are known. In particular, no enzyme has been found yet for introducing the acp3U modification at position 47 in the variable loop of eight E. coli tRNAs. Here we identify the so far functionally uncharacterized YfiP protein as the SAM-dependent 3-amino-3-carboxypropyl transferase catalyzing this modification and thereby extend the list of known tRNA modification enzymes in E. coli. Similar to the Tsr3 enzymes that introduce acp modifications at U or m1Ψ nucleotides in rRNAs this protein conta…
Tema 11. El Tribunal Penal Internacional
2019
Presentació del Tema 11, titulat "El Tribunal Penal Internacional" de l'assignatura Relacions i Organitzacions Internacionals. Curs 2018-19.
La psicoteràpia trnasforma la praxis moral?
2018
espanolEsta investigacion se inicio en el ano 2014 con el objetivo principal de conocer si los pacientes que realizan una psicoterapia cambian su praxis moral. Otros objetivos eran descubrir asociaciones significativas entre subgrupos de la muestra. La muestra se capto principalmente por internet. Los datos recogidos son: sociodemograficos; el cuestionario de personalidad MCMI y la evaluacion de unos dilemas eticos con respuestas dicotomicas y con una explicacion descriptiva. Los dilemas sedisenaron especificamente para la investigacion. El analisis se ha efectuado con herramientas cualitativas (Atlas.ti) y cuantitativas (SPSS) sobre una muestra valida de 85 sujetos, y con la hipotesis nula…
Effects of 5-Azacitidine on Dnmt2/Trdmt1 expression levels and endoplasmic reticulum stress in cellular models of insulinoma
2021
Diabetes mellitus affects people all over the world of all ages or social groups making it a worldwide healthcare challenge. Moreover, untreated or badly treated diabetes carries a risk of serious complications including premature death (IDF Diabetes Atlas 9th edition, 2019). The main symptom of diabetes is insulin secretion and/or action disorder leading to hyperglycemia what results in impaired carbohydrate, fat, and protein metabolism (“Diagnosis and Classification of Diabetes Mellitus,” 2013). Dnmt2/ Trdmt1 in its structure and sequence is similar to DNA methyltransferases, however, it has been shown that mainly methylates aspartic acid transfer RNA, specifically at the cytosine-38 resi…
Sulfur transfer and activation by ubiquitin-like modifier system Uba4•Urm1 link protein urmylation and tRNA thiolation in yeast.
2017
Urm1 is a unique dual-function member of the ubiquitin protein family and conserved from yeast to man. It acts both as a protein modifier in ubiquitin-like urmylation and as a sulfur donor for tRNA thiolation, which in concert with the Elongator pathway forms 5-methoxy-carbonyl-methyl-2-thio (mcm5s2) modified wobble uridines (U34) in anticodons. Using Saccharomyces cerevisiae as a model to study a relationship between these two functions, we examined whether cultivation temperature and sulfur supply previously implicated in the tRNA thiolation branch of the URM1 pathway also contribute to proper urmylation. Monitoring Urm1 conjugation, we found urmylation of the peroxiredoxin Ahp1 is suppre…
Caracterización funcional de GTPBP3: una proteína G implicada en la modificación de tRNAs mitocondriales.
2015
Determinadas enfermedades mitocondriales, como MELAS (mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes), MERRF (myoclonus epilepsy associated with ragged-red-fibers), cardiomiopatía hipertrófica y acidosis láctica dependiente de GTPBP3, cardiomiopatía hipertrófica infantil y acidosis láctica dependiente de MTO1 y fallo hepático infantil agudo dependiente de TRMU, están asociadas con una disfunción severa del sistema de fosforilación oxidativa (OXPHOS) que, se cree, podría ser resultado de defectos en la modificación postranscripcional de la uridina localizada en la posición de tambaleo (U34) de ciertos tRNAs mitocondriales (mt-tRNAs) y, por consiguiente, de u…
Functional characterization of the human tRNA methyltransferases TRMT10A and TRMT10B
2020
Abstract The TRM10 family of methyltransferases is responsible for the N1-methylation of purines at position 9 of tRNAs in Archaea and Eukarya. The human genome encodes three TRM10-type enzymes, of which only the mitochondrial TRMT10C was previously characterized in detail, whereas the functional significance of the two presumably nuclear enzymes TRMT10A and TRMT10B remained unexplained. Here we show that TRMT10A is m1G9-specific and methylates a subset of nuclear-encoded tRNAs, whilst TRMT10B is the first m1A9-specific tRNA methyltransferase found in eukaryotes and is responsible for the modification of a single nuclear-encoded tRNA. Furthermore, we show that the lack of G9 methylation cau…