1
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Patiño-Guillén G, Pešović J, Panić M, Savić-Pavićević D, Bošković F, Keyser UF. Single-molecule RNA sizing enables quantitative analysis of alternative transcription termination. Nat Commun 2024; 15:1699. [PMID: 38402271 PMCID: PMC10894232 DOI: 10.1038/s41467-024-45968-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Accepted: 02/01/2024] [Indexed: 02/26/2024] Open
Abstract
Transcription, a critical process in molecular biology, has found many applications in RNA synthesis, including mRNA vaccines and RNA therapeutics. However, current RNA characterization technologies suffer from amplification and enzymatic biases that lead to loss of native information. Here, we introduce a strategy to quantitatively study both transcription and RNA polymerase behaviour by sizing RNA with RNA nanotechnology and nanopores. To begin, we utilize T7 RNA polymerase to transcribe linear DNA lacking termination sequences. Surprisingly, we discover alternative transcription termination in the origin of replication sequence. Next, we employ circular DNA without transcription terminators to perform rolling circle transcription. This allows us to gain valuable insights into the processivity and transcription behaviour of RNA polymerase at the single-molecule level. Our work demonstrates how RNA nanotechnology and nanopores may be used in tandem for the direct and quantitative analysis of RNA transcripts. This methodology provides a promising pathway for accurate RNA structural mapping by enabling the study of full-length RNA transcripts at the single-molecule level.
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Affiliation(s)
| | - Jovan Pešović
- University of Belgrade - Faculty of Biology, Centre for Human Molecular Genetics, Belgrade, Serbia
| | - Marko Panić
- University of Belgrade - Faculty of Biology, Centre for Human Molecular Genetics, Belgrade, Serbia
- Institute of Virology, Vaccines and Sera "Torlak", Belgrade, Serbia
| | - Dušanka Savić-Pavićević
- University of Belgrade - Faculty of Biology, Centre for Human Molecular Genetics, Belgrade, Serbia
| | - Filip Bošković
- Cavendish Laboratory, University of Cambridge, Cambridge, UK.
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2
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Arteaga SJ, Adams MS, Meyer NL, Richardson KE, Hoener S, Znosko BM. Thermodynamic determination of RNA duplex stability in magnesium solutions. Biophys J 2023; 122:565-576. [PMID: 36540026 PMCID: PMC9941723 DOI: 10.1016/j.bpj.2022.12.025] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Revised: 12/05/2022] [Accepted: 12/16/2022] [Indexed: 12/24/2022] Open
Abstract
The prediction of RNA secondary structure and thermodynamics from sequence relies on free energy minimization and nearest neighbor parameters. Currently, algorithms used to make these predictions are based on parameters from optical melting studies performed in 1 M NaCl. However, many physiological and biochemical buffers containing RNA include much lower concentrations of monovalent cations and the presence of divalent cations. In order to improve these algorithms, thermodynamic data was previously collected for RNA duplexes in solutions containing 71, 121, 221, and 621 mM Na+. From this data, correction factors for free energy (ΔG°37) and melting temperature (Tm) were derived. Despite these newly derived correction factors for sodium, the stabilizing effects of magnesium have been ignored. Here, the same RNA duplexes were melted in solutions containing 0.5, 1.5, 3.0, and 10.0 mM Mg2+ in the absence of monovalent cations. Correction factors for Tm and ΔG°37 were derived to scale the current parameters to a range of magnesium concentrations. The Tm correction factor predicts the melting temperature within 1.2°C, and the ΔG°37 correction factor predicts the free energy within 0.30 kcalmol. These newly derived magnesium correction factors can be incorporated into algorithms that predict RNA secondary structure and stability from sequence.
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Affiliation(s)
| | - Miranda S Adams
- Department of Chemistry, Saint Louis University, Saint Louis, Missouri
| | - Nicole L Meyer
- Department of Chemistry, Saint Louis University, Saint Louis, Missouri
| | | | - Scott Hoener
- Department of Chemistry, Saint Louis University, Saint Louis, Missouri
| | - Brent M Znosko
- Department of Chemistry, Saint Louis University, Saint Louis, Missouri.
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3
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Hori H. Transfer RNA Modification Enzymes with a Thiouridine Synthetase, Methyltransferase and Pseudouridine Synthase (THUMP) Domain and the Nucleosides They Produce in tRNA. Genes (Basel) 2023; 14:genes14020382. [PMID: 36833309 PMCID: PMC9957541 DOI: 10.3390/genes14020382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 01/25/2023] [Accepted: 01/27/2023] [Indexed: 02/04/2023] Open
Abstract
The existence of the thiouridine synthetase, methyltransferase and pseudouridine synthase (THUMP) domain was originally predicted by a bioinformatic study. Since the prediction of the THUMP domain more than two decades ago, many tRNA modification enzymes containing the THUMP domain have been identified. According to their enzymatic activity, THUMP-related tRNA modification enzymes can be classified into five types, namely 4-thiouridine synthetase, deaminase, methyltransferase, a partner protein of acetyltransferase and pseudouridine synthase. In this review, I focus on the functions and structures of these tRNA modification enzymes and the modified nucleosides they produce. Biochemical, biophysical and structural studies of tRNA 4-thiouridine synthetase, tRNA methyltransferases and tRNA deaminase have established the concept that the THUMP domain captures the 3'-end of RNA (in the case of tRNA, the CCA-terminus). However, in some cases, this concept is not simply applicable given the modification patterns observed in tRNA. Furthermore, THUMP-related proteins are involved in the maturation of other RNAs as well as tRNA. Moreover, the modified nucleosides, which are produced by the THUMP-related tRNA modification enzymes, are involved in numerous biological phenomena, and the defects of genes for human THUMP-related proteins are implicated in genetic diseases. In this review, these biological phenomena are also introduced.
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Affiliation(s)
- Hiroyuki Hori
- Department of Materials Science and Biotechnology, Graduate School of Science and Engineering, Ehime University, Matsuyama 790-8577, Japan
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4
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Distinct Modified Nucleosides in tRNA Trp from the Hyperthermophilic Archaeon Thermococcus kodakarensis and Requirement of tRNA m 2G10/m 2 2G10 Methyltransferase (Archaeal Trm11) for Survival at High Temperatures. J Bacteriol 2019; 201:JB.00448-19. [PMID: 31405913 DOI: 10.1128/jb.00448-19] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Accepted: 08/09/2019] [Indexed: 12/19/2022] Open
Abstract
tRNA m2G10/m2 2G10 methyltransferase (archaeal Trm11) methylates the 2-amino group in guanosine at position 10 in tRNA and forms N 2,N 2-dimethylguanosine (m2 2G10) via N 2-methylguanosine (m2G10). We determined the complete sequence of tRNATrp, one of the substrate tRNAs for archaeal Trm11 from Thermococcus kodakarensis, a hyperthermophilic archaeon. Liquid chromatography/mass spectrometry following enzymatic digestion of tRNATrp identified 15 types of modified nucleoside at 21 positions. Several modifications were found at novel positions in tRNA, including 2'-O-methylcytidine at position 6, 2-thiocytidine at position 17, 2'-O-methyluridine at position 20, 5,2'-O-dimethylcytidine at position 32, and 2'-O-methylguanosine at position 42. Furthermore, methylwyosine was found at position 37 in this tRNATrp, although 1-methylguanosine is generally found at this location in tRNATrp from other archaea. We constructed trm11 (Δtrm11) and some gene disruptant strains and compared their tRNATrp with that of the wild-type strain, which confirmed the absence of m2 2G10 and other corresponding modifications, respectively. The lack of 2-methylguanosine (m2G) at position 67 in the trm11 trm14 double disruptant strain suggested that this methylation is mediated by Trm14, which was previously identified as an m2G6 methyltransferase. The Δtrm11 strain grew poorly at 95°C, indicating that archaeal Trm11 is required for T. kodakarensis survival at high temperatures. The m2 2G10 modification might have effects on stabilization of tRNA and/or correct folding of tRNA at the high temperatures. Collectively, these results provide new clues to the function of modifications and the substrate specificities of modification enzymes in archaeal tRNA, enabling us to propose a strategy for tRNA stabilization of this archaeon at high temperatures.IMPORTANCE Thermococcus kodakarensis is a hyperthermophilic archaeon that can grow at 60 to 100°C. The sequence of tRNATrp from this archaeon was determined by liquid chromatography/mass spectrometry. Fifteen types of modified nucleoside were observed at 21 positions, including 5 modifications at novel positions; in addition, methylwyosine at position 37 was newly observed in an archaeal tRNATrp The construction of trm11 (Δtrm11) and other gene disruptant strains confirmed the enzymes responsible for modifications in this tRNA. The lack of 2-methylguanosine (m2G) at position 67 in the trm11 trm14 double disruptant strain suggested that this position is methylated by Trm14, which was previously identified as an m2G6 methyltransferase. The Δtrm11 strain grew poorly at 95°C, indicating that archaeal Trm11 is required for T. kodakarensis survival at high temperatures.
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5
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Marchand V, Blanloeil-Oillo F, Helm M, Motorin Y. Illumina-based RiboMethSeq approach for mapping of 2'-O-Me residues in RNA. Nucleic Acids Res 2016; 44:e135. [PMID: 27302133 PMCID: PMC5027498 DOI: 10.1093/nar/gkw547] [Citation(s) in RCA: 154] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Accepted: 06/06/2016] [Indexed: 12/22/2022] Open
Abstract
RNA 2′-O-methylation is one of the ubiquitous nucleotide modifications found in many RNA types from Bacteria, Archaea and Eukarya. RNAs bearing 2′-O-methylations show increased resistance to degradation and enhanced stability in helices. While the exact role of each 2′-O-Me residue remained elusive, the catalytic protein Fibrillarin (Nop1 in yeast) responsible for 2′-O-methylation in eukaryotes, is associated with human pathologies. Therefore, there is an urgent need to precisely map and quantify hundreds of 2′-O-Me residues in RNA using high-throughput technologies. Here, we develop a reliable protocol using alkaline fragmentation of total RNA coupled to a commonly used ligation approach, and Illumina sequencing. We describe a methodology to detect 2′-O-methylations with high sensitivity and reproducibility even with limited amount of starting material (1 ng of total RNA). The method provides a quantification of the 2′-O-methylation occupancy of a given site, allowing to detect relatively small changes (>10%) in 2′-O-methylation profiles. Altogether this technique unlocks a technological barrier since it will be applicable for routine parallel treatment of biological and clinical samples to decipher the functions of 2′-O-methylations in pathologies.
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Affiliation(s)
- Virginie Marchand
- IMoPA UMR7365 CNRS-UL, BioPole Lorraine University, 9 avenue de la Foret de Haye, 54505 Vandoeuvre-les-Nancy, France Next-Generation Sequencing Core Facility, FR3209 BMCT, Lorraine University, 9 avenue de la Foret de Haye, 54505 Vandoeuvre-les-Nancy, France
| | - Florence Blanloeil-Oillo
- IMoPA UMR7365 CNRS-UL, BioPole Lorraine University, 9 avenue de la Foret de Haye, 54505 Vandoeuvre-les-Nancy, France Next-Generation Sequencing Core Facility, FR3209 BMCT, Lorraine University, 9 avenue de la Foret de Haye, 54505 Vandoeuvre-les-Nancy, France
| | - Mark Helm
- Institute of Pharmacy and Biochemistry, Johannes Gutenberg University Mainz, Staudingerweg 5, 55128 Mainz, Germany
| | - Yuri Motorin
- IMoPA UMR7365 CNRS-UL, BioPole Lorraine University, 9 avenue de la Foret de Haye, 54505 Vandoeuvre-les-Nancy, France Next-Generation Sequencing Core Facility, FR3209 BMCT, Lorraine University, 9 avenue de la Foret de Haye, 54505 Vandoeuvre-les-Nancy, France
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6
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Dammertz K, Hengesbach M, Helm M, Nienhaus GU, Kobitski AY. Single-Molecule FRET Studies of Counterion Effects on the Free Energy Landscape of Human Mitochondrial Lysine tRNA. Biochemistry 2011; 50:3107-15. [DOI: 10.1021/bi101804t] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
| | - Martin Hengesbach
- Institute of Pharmacy and Molecular Biotechnology, Heidelberg University, 69120 Heidelberg, Germany
| | - Mark Helm
- Institute of Pharmacy and Molecular Biotechnology, Heidelberg University, 69120 Heidelberg, Germany
- Institute of Pharmacy and Biochemistry, University of Mainz, 55128 Mainz, Germany
| | - G. Ulrich Nienhaus
- Institute of Applied Physics and Center for Functional Nanostructures (CFN), Karlsruhe Institute of Technology (KIT), 76128 Karlsruhe, Germany
- Department of Physics, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
| | - Andrei Yu. Kobitski
- Institute of Applied Physics and Center for Functional Nanostructures (CFN), Karlsruhe Institute of Technology (KIT), 76128 Karlsruhe, Germany
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7
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Makarov P, Kropf S, Wiswedel I, Augustin W, Schild L. Consumption of redox energy by glutathione metabolism contributes to hypoxia/ reoxygenation-induced injury in astrocytes. Mol Cell Biochem 2006; 286:95-101. [PMID: 16583144 DOI: 10.1007/s11010-005-9098-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2005] [Accepted: 11/30/2005] [Indexed: 11/30/2022]
Abstract
The role of glutathione during ischemia/reperfusion is still a controversial issue. Glutathione should exert beneficial effects in the situation of ischemia/reperfusion due to its antioxidative potency. However, increasing survival time after transient ischemia and hypoxia has been reported for glutathione depleted cells. This work was aimed to analyse whether glutathione metabolism essentially contributes to redox energy failure and subsequent cell damage during ischemia/reperfusion. For this purpose, primary astrocyte rich cell cultures were subjected to 1 h hypoxia followed by up to 4 h reoxygenation in combination with substrate deprivation and glutathione depletion. The ability of the cells to reduce MTT was used to quantify the redox power of the cells. Inhibition of glutathione synthesis by L-buthionine-(S,R)-sulfoximine (BSO) caused depletion of cellular glutathione within 24 h and increase in MTT reduction by about 10% under normoxic conditions. Reoxygenation following 1 h of hypoxia was associated with decrease in MTT reduction which was enhanced by substrate deprivation. Glutathione depletion reduced hypoxia-induced decrease in MTT reduction. Three hours of substrate deprivation prior hypoxia resulted in lower levels of MTT reduction during reoxygenaton. Our data suggest that in situations of oxidative stress such as ischemia/reperfusion, glutathione metabolism may causes decrease of the cellular redox energy below a threshold level required for basic cellular functions finally resulting in cell injury.
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Affiliation(s)
- Petr Makarov
- Institute of Clinical Chemistry and Pathological Biochemistry, Department of Pathological Biochemistry, Medical Faculty, Otto-von-Guericke-University Magdeburg, Magdeburg, Germany
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8
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Shimokawa N, Dikic I, Sugama S, Koibuchi N. Molecular responses to acidosis of central chemosensitive neurons in brain. Cell Signal 2005; 17:799-808. [PMID: 15763422 DOI: 10.1016/j.cellsig.2005.01.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2004] [Revised: 12/24/2004] [Accepted: 01/07/2005] [Indexed: 11/22/2022]
Abstract
Significant advances have been made in understanding how neurons sense and respond to acidosis at the cellular level. Decrease in pH of the cerebrospinal fluid followed by hypercapnia (increased arterial CO2) is monitored by the chemosensory neurons of the medulla oblongata. Then the intracellular signalling pathways are activated to regulate specific gene expression, which leads to a hyperventilatory response. However, little is known about molecular details of such cellular responses. Recent studies have identified several transcription factors such as c-Jun, Fos and small Maf proteins that may play critical roles in the brain adaptation to hypercapnia. Hypercapnic stimulation also activates c-Jun NH2-terminal kinase (JNK) cascade via influx of extracellular Ca2+ through voltage-gated Ca2+ channels. In addition, several transmembrane proteins including Rhombex-29 (rhombencephalic expression protein-29 kDa) and Past-A (proton-associated sugar transporter-A) have been implicated in regulation of H+ sensitivity and brain acidosis-mediated energy metabolism, respectively. This review discusses current knowledge on the signalling mechanisms and molecular basis of neuronal adaptation during acidosis.
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Affiliation(s)
- Noriaki Shimokawa
- Department of Integrative Physiology, Gunma University Graduate School of Medicine, 3-39-22 Showa-machi, Maebashi-shi 371-8511, Japan.
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9
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Abstract
The present study demonstrates a high level of the nuclear Transformer 2alpha (Tra2alpha) protein in adult mouse brain relative to other tissues, including muscle, heart, liver, lungs, kidney and small intestine, suggesting the potential importance of Tra2alpha in neural function. The level of Tra2alpha in mouse cerebrum is developmentally regulated, peaking at neonate stage. In P19 carcinoma cells, Tra2alpha is transiently up-regulated upon retinoic acid (RA) treatment. Although over-expression of Tra2alpha protein alone does not elicit P19 differentiation, under these conditions the response of P19 cells to RA is significantly increased. The results suggest that Tra2alpha proteins may act as a mediator in the signal pathway associated with RA-induced differentiation in P19 cells.
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Affiliation(s)
- Xianhua Chen
- Laboratory of Genomic Physiology, Center for Brain Research, State Key laboratory of Medical Neurobiology, School of Life Sciences, Fudan University, 220 Handan Road, Shanghai 200433, China
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10
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Unni E, Su S, Zraly CB, Mattox W. Analysis of a null mutation in the Drosophila splicing regulator Tra2 suggests its function is restricted to sexual differentiation. Genesis 2004; 37:76-83. [PMID: 14595843 DOI: 10.1002/gene.10234] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Tra2 is a regulator of pre-mRNA splicing and a key component of the Drosophila somatic sex determination pathway. Functional orthologs of this protein are thought to perform nonsex-specific functions essential for viability in both vertebrates and nematodes. Although Drosophila Tra2 is expressed throughout the soma of both sexes, studies on it have focused only on the sex-specific phenotypes of known viable alleles. Here we show that that widely used tra2 mutant alleles have residual activity and are not suitable for evaluating its effect on viability. To test whether Tra2 has an essential role in development, we generated a transposon-induced deletion in critical coding sequences. We find that tra2 deletion adults can survive as well as their heterozygous siblings. Thus, in contrast to other organisms, Tra2 is not required in Drosophila for general viability under laboratory conditions.
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Affiliation(s)
- Emmanual Unni
- Department of Molecular Genetics, University of Texas, M.D. Anderson Cancer Center, Houston, Texas, USA
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12
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Amora Y, Chevionb M, Levinea A. Anoxia pretreatment protects soybean cells against H(2)O(2)-induced cell death: possible involvement of peroxidases and of alternative oxidase. FEBS Lett 2000; 477:175-80. [PMID: 10908716 DOI: 10.1016/s0014-5793(00)01797-x] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Anoxia followed by reoxygenation causes extensive damage to cellular components through generation of reactive oxygen intermediates. We examined cellular responses to oxidative stress after anoxia in cultured soybean or human fibroblast cells. Anoxia pretreatment protected soybean but not fibroblasts against H(2)O(2) concentrations that induced programmed cell death in normoxic cells. H(2)O(2) removal in anoxia-pretreated soybean cultures was faster. Protection was associated with increased action of alternative oxidase (AOX) and peroxidases. AOX inhibitors abolished the protective effect, while induction of AOX protected normoxic cells against H(2)O(2). We propose that during anoxia, plant cells can prepare for reoxygenation injury by up-regulating their antioxidant capacity, and that AOX is involved in this process.
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Affiliation(s)
- Y Amora
- Department of Plant Sciences, Hebrew University of Jerusalem, Jerusalem Givat-Ram 91904, Israel, USA
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13
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Perreau VM, Keith G, Holmes WM, Przykorska A, Santos MA, Tuite MF. The Candida albicans CUG-decoding ser-tRNA has an atypical anticodon stem-loop structure. J Mol Biol 1999; 293:1039-53. [PMID: 10547284 DOI: 10.1006/jmbi.1999.3209] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In many Candida species, the leucine CUG codon is decoded by a tRNA with two unusual properties: it is a ser-tRNA and, uniquely, has guanosine at position 33 (G33). Using a combination of enzymatic (V1 RNase, RnI nuclease) and chemical (Pb(2+), imidazole) probing of the native Candida albicans ser-tRNACAG, we demonstrate that the overall tertiary structure of this tRNA resembles that of a ser-tRNA rather than a leu-tRNA, except within the anticodon arm where there is considerable disruption of the anticodon stem. Using non-modified in vitro transcripts of the C. albicans ser-tRNACAG carrying G, C, U or A at position 33, we demonstrate that it is specifically a G residue at this position that induces the atypical anticodon stem structure. Further quantitative evidence for an unusual structure in the anticodon arm of the G33-tRNA is provided by the observed change in kinetics of methylation of the G at position 37, by purified Escherichia coli m(1)G37 methyltransferase. We conclude that the anticodon arm distortion, induced by a guanosine base at position 33 in the anticodon loop of this novel tRNA, results in reduced decoding ability which has facilitated the evolution of this tRNA without extinction of the species encoding it.
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MESH Headings
- Anticodon/chemistry
- Anticodon/genetics
- Anticodon/metabolism
- Base Sequence
- Candida albicans/genetics
- Evolution, Molecular
- Genetic Code/genetics
- Imidazoles/metabolism
- Lead/metabolism
- Methylation
- Mutation/genetics
- Nucleic Acid Conformation
- Nucleosides/genetics
- Nucleosides/metabolism
- RNA, Fungal/chemistry
- RNA, Fungal/genetics
- RNA, Fungal/metabolism
- RNA, Transfer, Ser/chemistry
- RNA, Transfer, Ser/genetics
- RNA, Transfer, Ser/metabolism
- Ribonucleases/metabolism
- Saccharomyces cerevisiae/genetics
- Solutions
- tRNA Methyltransferases/metabolism
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Affiliation(s)
- V M Perreau
- Research School of Biosciences, University of Kent, Canterbury, Kent, CT2 7NJ, UK
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14
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Honma Y, Kiyosawa H, Mori T, Oguri A, Nikaido T, Kanazawa K, Tojo M, Takeda J, Tanno Y, Yokoya S, Kawabata I, Ikeda H, Wanaka A. Eos: a novel member of the Ikaros gene family expressed predominantly in the developing nervous system. FEBS Lett 1999; 447:76-80. [PMID: 10218586 DOI: 10.1016/s0014-5793(99)00265-3] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
We identified a novel member of the Ikaros gene family, which has critical roles in the development of lymphoid lineages. This gene, which we named Eos, was expressed predominantly in the developing central and peripheral nervous system. Eos protein could interact with itself and Ikaros protein through its C-terminal portion in the yeast two hybrid assay. These findings suggested that Eos may have important roles in neural development similarly to the Ikaros family in the development of hemolymphoid tissue.
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Affiliation(s)
- Y Honma
- Department of Cell Science, Institute of Biomedical Sciences, Fukushima Medical University School of Medicine, Fukushima City, Japan
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15
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Abstract
New intron-containing genes encoding tRNAs were discovered when genomic DNA isolated from various animal species was amplified by the polymerase chain reaction (PCR) with primers based on sequences of rabbit tRNA(Lys). From sequencing analysis of the products of PCR, we found that introns are present in several genes encoding tRNA(Lys) in mollusks, such as Loligo bleekeri (squid) and Octopus vulgaris (octopus). These introns were specific to genes encoding tRNA(Lys)(CUU) and were not present in genes encoding tRNA(Lys)(CUU). In addition, the sequences of the introns were different from one another. To confirm the results of our initial experiments, we isolated and sequenced genes encoding tRNA(Lys)(CUU) and tRNA(Lys)(UUU). The gene for tRNA(Lys)(UUU) from squid contained an intron, whose sequence was the same as that identified by PCR, and the gene formed a cluster with a corresponding pseudogene. Several DNA regions of 2.1 kb containing this cluster appeared to be tandemly arrayed in the squid genome. By contrast, the gene encoding tRNA(Lys)(CUU) did not contain an intron, as shown also by PCR. The tRNA(Lys)(UUU) that corresponded to the analyzed gene was isolated and characterized. The present study provides the first example of an intron-containing gene encoding a tRNA in mollusks and suggests the universality of introns in such genes in higher eukaryotes.
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Affiliation(s)
- M Matsuo
- Faculty of Bioscience and Biotechnology, Tokyo Institute of Technology, Yokohama, Japan
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