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tRNA methylation

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https://www.readbyqxmd.com/read/29222331/a-hypertension-associated-mitochondrial-dna-mutation-introduces-an-m1g37-modification-into-trnamet-altering-its-structure-and-function
#1
Mi Zhou, Ling Xue, Yaru Chen, Haiying Li, Qiufen He, Bibin Wang, Feilong Meng, Meng Wang, Min-Xin Guan
Defective nucleotide modifications of mitochondrial tRNAs have been associated with several human diseases, but their pathophysiology remains poorly understood. In this report, we investigated the pathogenic molecular mechanism underlying a hypertension-associated 4435A>G mutation in mitochondrial tRNAMet The m.4435A>G mutation affected a highly conserved adenosine at position 37, 3' adjacent to the tRNA's anticodon, which is important for the fidelity of codon recognition and stabilization. We hypothesized that the m...
December 8, 2017: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/29214216/structural-insight-into-the-methyltransfer-mechanism-of-the-bifunctional-trm5
#2
Caiyan Wang, Qian Jia, Jianhua Zeng, Ran Chen, Wei Xie
The wyosine derivatives present at position 37 in transfer RNAs (tRNAs) are critical for reading frame maintenance. The methyltransferase Trm5a from Pyrococcus abyssi (PaTrm5a) plays a key role in this hypermodification process in generating m1G37 and imG2, two products of the wyosine biosynthetic pathway, through two methyl transfers to distinct substrates, but the mechanism is currently unknown. We report two cocrystal structures of PaTrm5a in complex with tRNAPhe and reveal the structural basis for substrate recognition, which was supported by in vitro activity assays...
December 2017: Science Advances
https://www.readbyqxmd.com/read/29198561/transcriptome-wide-analysis-of-roles-for-trna-modifications-in-translational-regulation
#3
Hsin-Jung Chou, Elisa Donnard, H Tobias Gustafsson, Manuel Garber, Oliver J Rando
Covalent nucleotide modifications in noncoding RNAs affect a plethora of biological processes, and new functions continue to be discovered even for well-known modifying enzymes. To systematically compare the functions of a large set of noncoding RNA modifications in gene regulation, we carried out ribosome profiling in budding yeast to characterize 57 nonessential genes involved in tRNA modification. Deletion mutants exhibited a range of translational phenotypes, with enzymes known to modify anticodons, or non-tRNA substrates such as rRNA, exhibiting the most dramatic translational perturbations...
November 17, 2017: Molecular Cell
https://www.readbyqxmd.com/read/29191170/the-arabidopsis-elp3-elo3-and-elp4-elo1-genes-enhance-disease-resistance-in-fragaria-vesca-l
#4
Katchen Julliany P Silva, Asha M Brunings, Juliana A Pereira, Natalia A Peres, Kevin M Folta, Zhonglin Mou
BACKGROUND: Plant immune response is associated with a large-scale transcriptional reprogramming, which is regulated by numerous transcription regulators such as the Elongator complex. Elongator is a multitasking protein complex involved in diverse cellular processes, including histone modification, DNA methylation, and tRNA modification. In recent years, Elongator is emerging as a key regulator of plant immune responses. However, characterization of Elongator's function in plant immunity has been conducted only in the model plant Arabidopsis thaliana...
December 1, 2017: BMC Plant Biology
https://www.readbyqxmd.com/read/29170010/elongator-%C3%AC-a-trna-modifying-complex-that-promotes-efficient-translational-decoding
#5
REVIEW
Marcus J O Johansson, Fu Xu, Anders S Byström
Naturally occurring modifications of the nucleosides in the anticodon region of tRNAs influence their translational decoding properties. Uridines present at the wobble position in eukaryotic cytoplasmic tRNAs often contain a 5-carbamoylmethyl (ncm(5)) or 5-methoxycarbonylmethyl (mcm(5)) side-chain and sometimes also a 2-thio or 2'-O-methyl group. The first step in the formation of the ncm(5) and mcm(5) side-chains requires the conserved six-subunit Elongator complex. Although Elongator has been implicated in several different cellular processes, accumulating evidence suggests that its primary, and possibly only, cellular function is to promote modification of tRNAs...
November 20, 2017: Biochimica et Biophysica Acta
https://www.readbyqxmd.com/read/29163634/evidence-suggesting-absence-of-mitochondrial-dna-methylation
#6
Mie Mechta, Lars R Ingerslev, Odile Fabre, Martin Picard, Romain Barrès
Methylation of nuclear genes encoding mitochondrial proteins participates in the regulation of mitochondria function. The existence of cytosine methylation in the mitochondrial genome is debated. To investigate whether mitochondrial DNA (mtDNA) is methylated, we used both targeted- and whole mitochondrial genome bisulfite sequencing in cell lines and muscle tissue from mouse and human origin. While unconverted cytosines were detected in some portion of the mitochondrial genome, their abundance was inversely associated to the sequencing depth, indicating that sequencing analysis can bias the estimation of mtDNA methylation levels...
2017: Frontiers in Genetics
https://www.readbyqxmd.com/read/29155943/logical-engineering-of-d-arm-and-t-stem-of-trna-that-enhances-d-amino-acid-incorporation
#7
Takayuki Katoh, Yoshihiko Iwane, Hiroaki Suga
A bacterial translation factor EF-P alleviates ribosomal stalling caused by polyproline sequence by accelerating Pro-Pro formation. EF-P recognizes a specific D-arm motif found in tRNAPro isoacceptors, 9-nt D-loop closed by a stable D-stem sequence, for Pro-selective peptidyl-transfer acceleration. It is also known that the T-stem sequence on aminoacyl-tRNAs modulates strength of the interaction with EF-Tu, giving enhanced incorporation of non-proteinogenic amino acids such as some N-methyl amino acids. Based on the above knowledge, we logically engineered tRNA's D-arm and T-stem sequences to investigate a series of tRNAs for the improvement of consecutive incorporation of d-amino acids and an α, α-disubstituted amino acid...
November 16, 2017: Nucleic Acids Research
https://www.readbyqxmd.com/read/29131848/high-throughput-m6a-seq-reveals-rna-m6a-methylation-patterns-in-the-chloroplast-and-mitochondria-transcriptomes-of-arabidopsis-thaliana
#8
Zegang Wang, Kai Tang, Dayong Zhang, Yizhen Wan, Yan Wen, Quanyou Lu, Lei Wang
This study is the first to comprehensively characterize m6A patterns in the Arabidopsis chloroplast and mitochondria transcriptomes based on our open accessible data deposited in NCBI's Gene Expression Omnibus with GEO Series accession number of GSE72706. Over 86% of the transcripts were methylated by m6A in the two organelles. Over 550 and 350 m6A sites were mapped, with ~5.6 to ~5.8 and ~4.6 to ~4.9 m6A sites per transcript, to the chloroplast and mitochondria genome, respectively. The overall m6A methylation extent in the two organelles was greatly higher than that in the nucleus...
2017: PloS One
https://www.readbyqxmd.com/read/29103146/rna-cytosine-methyltransferase-nsun3-regulates-embryonic-stem-cell-differentiation-by-promoting-mitochondrial-activity
#9
Lukas Trixl, Thomas Amort, Alexandra Wille, Manuela Zinni, Susanne Ebner, Clara Hechenberger, Felix Eichin, Hanna Gabriel, Ines Schoberleitner, Anming Huang, Paolo Piatti, Roxana Nat, Jakob Troppmair, Alexandra Lusser
Chemical modifications of RNA have been attracting increasing interest because of their impact on RNA fate and function. Therefore, the characterization of enzymes catalyzing such modifications is of great importance. The RNA cytosine methyltransferase NSUN3 was recently shown to generate 5-methylcytosine in the anticodon loop of mitochondrial tRNA(Met). Further oxidation of this position is required for normal mitochondrial translation and function in human somatic cells. Because embryonic stem cells (ESCs) are less dependent on oxidative phosphorylation than somatic cells, we examined the effects of catalytic inactivation of Nsun3 on self-renewal and differentiation potential of murine ESCs...
November 4, 2017: Cellular and Molecular Life Sciences: CMLS
https://www.readbyqxmd.com/read/29072297/the-m-1-a-landscape-on-cytosolic-and-mitochondrial-mrna-at-single-base-resolution
#10
Modi Safra, Aldema Sas-Chen, Ronit Nir, Roni Winkler, Aharon Nachshon, Dan Bar-Yaacov, Matthias Erlacher, Walter Rossmanith, Noam Stern-Ginossar, Schraga Schwartz
Modifications on mRNA offer the potential of regulating mRNA fate post-transcriptionally. Recent studies suggested the widespread presence of N(1)-methyladenosine (m(1)A), which disrupts Watson-Crick base pairing, at internal sites of mRNAs. These studies lacked the resolution of identifying individual modified bases, and did not identify specific sequence motifs undergoing the modification or an enzymatic machinery catalysing them, rendering it challenging to validate and functionally characterize putative sites...
October 25, 2017: Nature
https://www.readbyqxmd.com/read/29069453/kinetic-characterization-of-substrate-binding-sites-of-thermostable-trna-methyltransferase-trmb
#11
Chie Tomikawa, Kazuyuki Takai, Hiroyuki Hori
TrmB is a eubacterial tRNA methyltransferase which catalyzes the formation of N 7-methylguanosine at position 46 (m 7 G46) in tRNA consuming S-adenosyl-L-methionine (AdoMet) as the methyl group donor during the reaction. Previously, we purified TrmB from Aquifex aeolicus , a hyper-thermophilic eubacterium, and clarified the recognition sites in tRNA. Furthermore, we reported that an additional C-terminal region of A. aeolicus TrmB is required for protein stability at high temperatures. In the current study, we devised a new purification method to remove contaminating RNA completely...
October 23, 2017: Journal of Biochemistry
https://www.readbyqxmd.com/read/29042505/binding-synergy-as-an-essential-step-for-trna-editing-and-modification-enzyme-co-dependence-in-trypanosoma-brucei
#12
Katherine Mary McKenney, Mary Anne T Rubio, Juan D Alfonzo
Transfer RNAs acquire a variety of naturally occurring chemical modifications during their maturation; these fine-tune their structure and decoding properties in a manner critical for protein synthesis. We recently reported that in the eukaryotic parasite, Trypanosoma brucei, a methylation and deamination event are unexpectedly interconnected, whereby the tRNA adenosine deaminase (TbADAT2/3) and the 3-methylcytosine methyltransferase (TbTrm140) strictly rely on each other for activity, leading to formation of m(3)C and m(3)U at position 32 in several tRNAs...
October 17, 2017: RNA
https://www.readbyqxmd.com/read/29033456/the-dna-methyltransferase-family-a-versatile-toolkit-for-epigenetic-regulation
#13
REVIEW
Frank Lyko
The DNA methyltransferase (DNMT) family comprises a conserved set of DNA-modifying enzymes that have a central role in epigenetic gene regulation. Recent studies have shown that the functions of the canonical DNMT enzymes - DNMT1, DNMT3A and DNMT3B - go beyond their traditional roles of establishing and maintaining DNA methylation patterns. This Review analyses how molecular interactions and changes in gene copy numbers modulate the activity of DNMTs in diverse gene regulatory functions, including transcriptional silencing, transcriptional activation and post-transcriptional regulation by DNMT2-dependent tRNA methylation...
October 16, 2017: Nature Reviews. Genetics
https://www.readbyqxmd.com/read/28965832/5-methylcytosine-rna-methylation-in-arabidopsis-thaliana
#14
Xuean Cui, Zhe Liang, Lisha Shen, Qian Zhang, Shengjie Bao, Yuke Geng, Bin Zhang, Vonny Leo, Leah A Vardy, Tiegang Lu, Xiaofeng Gu, Hao Yu
5-Methylcytosine (m(5)C) is a well-characterized DNA modification, and is also predominantly reported in abundant non-coding RNAs in both prokaryotes and eukaryotes. However, the distribution and biological functions of m(5)C in plant mRNAs remain largely unknown. Here, we report transcriptome-wide profiling of RNA m(5)C in Arabidopsis thaliana by applying m(5)C RNA immunoprecipitation followed by a deep-sequencing approach (m(5)C-RIP-seq). LC-MS/MS and dot blot analyses reveal a dynamic pattern of m(5)C mRNA modification in various tissues and at different developmental stages...
November 6, 2017: Molecular Plant
https://www.readbyqxmd.com/read/28919411/homocysteine-upregulates-interleukin-17a-expression-via-nsun2-mediated-rna-methylation-in-t-lymphocytes
#15
Nan Wang, Hao Tang, Xian Wang, Wengong Wang, Juan Feng
Interleukin-17A (IL-17A) has been proven to participate in the process of various autoimmune diseases. The elevation of plasma homocysteine (Hcy), known as hyperhomocysteinemia (HHcy), is related to various chronic inflammatory diseases. Though HHcy-induced upregulation of IL-17A expression in T lymphocytes has been examined, the way in which IL-17A is regulated remains unclear. In this study, western blotting assays showed that Hcy (100 μM) upregulated NOP2/Sun domain family, member 2 (NSun2) expression in rat T lymphocytes...
November 4, 2017: Biochemical and Biophysical Research Communications
https://www.readbyqxmd.com/read/28911863/the-crystal-structure-of-the-pyrococcus-abyssi-mono-functional-methyltransferase-patrm5b
#16
Jialiang Wu, Qian Jia, Saibin Wu, Hui Zeng, Yujie Sun, Caiyan Wang, Ruiguang Ge, Wei Xie
The wyosine hypermodification found exclusively at G37 of tRNA(Phe) in eukaryotes and archaea is a very complicated process involving multiple steps and enzymes, and the derivatives are essential for the maintenance of the reading frame during translation. In the archaea Pyrococcus abyssi, two key enzymes from the Trm5 family, named PaTrm5a and PaTrm5b respectively, start the process by forming N1-methylated guanosine (m(1)G37). In addition, PaTrm5a catalyzes the further methylation of C7 on 4-demethylwyosine (imG-14) to produce isowyosine (imG2) at the same position...
November 4, 2017: Biochemical and Biophysical Research Communications
https://www.readbyqxmd.com/read/28911116/mechanistic-features-of-the-atypical-trna-m1g9-spout-methyltransferase-trm10
#17
Aiswarya Krishnamohan, Jane E Jackman
The tRNA m1G9 methyltransferase (Trm10) is a member of the SpoU-TrmD (SPOUT) superfamily of methyltransferases, and Trm10 homologs are widely conserved throughout Eukarya and Archaea. Despite possessing the trefoil knot characteristic of SPOUT enzymes, Trm10 does not share the same quaternary structure or key sequences with other members of the SPOUT family, suggesting a novel mechanism of catalysis. To investigate the mechanism of m1G9 methylation by Trm10, we performed a biochemical and kinetic analysis of Trm10 and variants with alterations in highly conserved residues, using crystal structures solved in the absence of tRNA as a guide...
September 6, 2017: Nucleic Acids Research
https://www.readbyqxmd.com/read/28888424/novel-patient-missense-mutations-in-the-hsd17b10-gene-affect-dehydrogenase-and-mitochondrial-trna-modification-functions-of-the-encoded-protein
#18
Stephanie Oerum, Martine Roovers, Michael Leichsenring, Cécile Acquaviva-Bourdain, Frauke Beermann, Corinne Gemperle-Britschgi, Alain Fouilhoux, Anne Korwitz-Reichelt, Henry J Bailey, Louis Droogmans, Udo Oppermann, Jörn Oliver Sass, Wyatt W Yue
MRPP2 (also known as HSD10/SDR5C1) is a multifunctional protein that harbours both catalytic and non-catalytic functions. The protein belongs to the short-chain dehydrogenase/reductases (SDR) family and is involved in the catabolism of isoleucine in vivo and steroid metabolism in vitro. MRPP2 also moonlights in a complex with the MRPP1 (also known as TRMT10C) protein for N1-methylation of purines at position 9 of mitochondrial tRNA, and in a complex with MRPP1 and MRPP3 (also known as PRORP) proteins for 5'-end processing of mitochondrial precursor tRNA...
September 6, 2017: Biochimica et Biophysica Acta
https://www.readbyqxmd.com/read/28882222/role-of-the-trna-derived-small-rnas-in-cancer-new-potential-biomarkers-and-target-for-therapy
#19
Veronica Balatti, Yuri Pekarsky, Carlo M Croce
Noncoding RNAs are untranslated RNA molecules that can be divided into two main types: infrastructural, including transfer RNAs (tRNAs) and ribosomal RNAs (rRNAs), and regulatory, including long ncRNAs (lncRNAs) and small ncRNAs (sRNA). Among small ncRNA, the role of microRNAs (miRNAs) and Piwi-interacting RNAs (piRNAs) in cancer is well documented. Recently, other small ncRNAs have been described. In particular, tRNA-derived small RNAs (tsRNA) have been found to be frequently dysregulated in cancer. Since tsRNAs can be considered unique sequences and are able to bind both Argonaute proteins (like miRNAs) and Piwi proteins (like piRNAs), their dysregulation could play a critical role in cancer by interfering with gene expression regulation at different levels...
2017: Advances in Cancer Research
https://www.readbyqxmd.com/read/28775286/elp3-and-dph3-of-schizosaccharomyces-pombe-mediate-cellular-stress-responses-through-trna-lys-uuu-modifications
#20
Desirée Villahermosa, Oliver Fleck
Efficient protein synthesis in eukaryotes requires diphthamide modification of translation elongation factor eEF2 and wobble uridine modifications of tRNAs. In higher eukaryotes, these processes are important for preventing neurological and developmental defects and cancer. In this study, we used Schizosaccharomyces pombe as a model to analyse mutants defective in eEF2 modification (dph1Δ), in tRNA modifications (elp3Δ), or both (dph3Δ) for sensitivity to cytotoxic agents and thermal stress. The dph3Δ and elp3Δ mutants were sensitive to a range of drugs and had growth defects at low temperature...
August 3, 2017: Scientific Reports
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