1
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Seys FM, Humphreys CM, Tomi-Andrino C, Li Q, Millat T, Yang S, Minton NP. Base editing enables duplex point mutagenesis in Clostridium autoethanogenum at the price of numerous off-target mutations. Front Bioeng Biotechnol 2023; 11:1211197. [PMID: 37496853 PMCID: PMC10366002 DOI: 10.3389/fbioe.2023.1211197] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Accepted: 06/06/2023] [Indexed: 07/28/2023] Open
Abstract
Base editors are recent multiplex gene editing tools derived from the Cas9 nuclease of Streptomyces pyogenes. They can target and modify a single nucleotide in the genome without inducing double-strand breaks (DSB) of the DNA helix. As such, they hold great potential for the engineering of microbes that lack effective DSB repair pathways such as homologous recombination (HR) or non-homologous end-joining (NHEJ). However, few applications of base editors have been reported in prokaryotes to date, and their advantages and drawbacks have not been systematically reported. Here, we used the base editors Target-AID and Target-AID-NG to introduce nonsense mutations into four different coding sequences of the industrially relevant Gram-positive bacterium Clostridium autoethanogenum. While up to two loci could be edited simultaneously using a variety of multiplexing strategies, most colonies exhibited mixed genotypes and most available protospacers led to undesired mutations within the targeted editing window. Additionally, fifteen off-target mutations were detected by sequencing the genome of the resulting strain, among them seven single-nucleotide polymorphisms (SNP) in or near loci bearing some similarity with the targeted protospacers, one 15 nt duplication, and one 12 kb deletion which removed uracil DNA glycosylase (UDG), a key DNA repair enzyme thought to be an obstacle to base editing mutagenesis. A strategy to process prokaryotic single-guide RNA arrays by exploiting tRNA maturation mechanisms is also illustrated.
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Affiliation(s)
- François M. Seys
- Clostridia Research Group, BBSRC/EPSRC Synthetic Biology Research Centre (SBRC), School of Life Sciences, Biodiscovery Institute, University of Nottingham, Nottingham, United Kingdom
| | - Christopher M. Humphreys
- Clostridia Research Group, BBSRC/EPSRC Synthetic Biology Research Centre (SBRC), School of Life Sciences, Biodiscovery Institute, University of Nottingham, Nottingham, United Kingdom
| | - Claudio Tomi-Andrino
- Clostridia Research Group, BBSRC/EPSRC Synthetic Biology Research Centre (SBRC), School of Life Sciences, Biodiscovery Institute, University of Nottingham, Nottingham, United Kingdom
- Centre for Analytical Bioscience, Advanced Materials and Healthcare Technologies Division, School of Pharmacy, University of Nottingham, Nottingham, United Kingdom
- Nottingham BBSRC/EPSRC Synthetic Biology Research Centre (SBRC), School of Mathematical Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Qi Li
- College of Life Sciences, Sichuan Normal University, Chengdu, China
| | - Thomas Millat
- Clostridia Research Group, BBSRC/EPSRC Synthetic Biology Research Centre (SBRC), School of Life Sciences, Biodiscovery Institute, University of Nottingham, Nottingham, United Kingdom
| | - Sheng Yang
- Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Nigel P. Minton
- Clostridia Research Group, BBSRC/EPSRC Synthetic Biology Research Centre (SBRC), School of Life Sciences, Biodiscovery Institute, University of Nottingham, Nottingham, United Kingdom
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Peng G, He Y, Wang M, Ashraf MF, Liu Z, Zhuang C, Zhou H. The structural characteristics and the substrate recognition properties of RNase Z S1. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2021; 158:83-90. [PMID: 33302124 DOI: 10.1016/j.plaphy.2020.12.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 12/01/2020] [Indexed: 06/12/2023]
Abstract
TMS5 encodes an RNase ZS1 protein that can process ubiquitin-60S ribosomal protein L40 family (UbL40) mRNAs to regulate thermo-sensitive genic male sterility in rice. Despite the importance of this protein, the structural characteristics and substrate recognition properties of RNase ZS1 remain unclear. Here, we found that the variations in several conservative amino acids alter the activation of RNase ZS1, and its recognition of RNA substrates depends on the structure of RNA. RNase ZS1 acts as a homodimer. The conserved amino acids in or adjacent to enzyme center play a critical role in the enzyme activity of RNase ZS1 and the conserved amino acids that far from active center have little impact on its enzyme activity. The cleavage efficiency of RNase ZS1 for pre-tRNA-MetCAU35 and UbL401 mRNA with cloverleaf-like structure was higher than that of pre-tRNA-AspAUC9 and UbL404 mRNA with imperfect cloverleaf-like structure. This difference implies that the enzyme activity of RNase ZS1 depends on the cloverleaf-like structure of the RNA. Furthermore, the RNase ZS1 activity was not inhibited by the 5' leader sequence and 3' CCA motif of pre-tRNA. These findings provide new insights for studying the cleavage characteristics and substrate recognition properties of RNase ZS.
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Affiliation(s)
- Guoqing Peng
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Instrumental Analysis and Research Center, College of Life Sciences, South China Agricultural University, Guangzhou, 510642, China; Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, Guangdong, 510642, China
| | - Ying He
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Instrumental Analysis and Research Center, College of Life Sciences, South China Agricultural University, Guangzhou, 510642, China; Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, Guangdong, 510642, China
| | - Mumei Wang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Instrumental Analysis and Research Center, College of Life Sciences, South China Agricultural University, Guangzhou, 510642, China; Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, Guangdong, 510642, China
| | - Muhammad Furqan Ashraf
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Instrumental Analysis and Research Center, College of Life Sciences, South China Agricultural University, Guangzhou, 510642, China; Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, Guangdong, 510642, China
| | - Zhenlan Liu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Instrumental Analysis and Research Center, College of Life Sciences, South China Agricultural University, Guangzhou, 510642, China; Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, Guangdong, 510642, China
| | - Chuxiong Zhuang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Instrumental Analysis and Research Center, College of Life Sciences, South China Agricultural University, Guangzhou, 510642, China; Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, Guangdong, 510642, China
| | - Hai Zhou
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Instrumental Analysis and Research Center, College of Life Sciences, South China Agricultural University, Guangzhou, 510642, China; Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, Guangdong, 510642, China.
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Kato Y, Takahashi M, Seki M, Nashimoto M, Shimizu-Ibuka A. RNA-hydrolyzing activity of metallo-β-lactamase IMP-1. PLoS One 2020; 15:e0241557. [PMID: 33126240 PMCID: PMC7599082 DOI: 10.1371/journal.pone.0241557] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Accepted: 10/18/2020] [Indexed: 11/23/2022] Open
Abstract
Metallo-β-lactamases (MBLs) hydrolyze a wide range of β-lactam antibiotics. While all MBLs share a common αβ/βα-fold, there are many other proteins with the same folding pattern that exhibit different enzymatic activities. These enzymes, together with MBLs, form the MBL superfamily. Thermotoga maritima tRNase Z, a tRNA 3′ processing endoribonuclease of MBL-superfamily, and IMP-1, a clinically isolated MBL, showed a striking similarity in tertiary structure, despite low sequence homology. IMP-1 hydrolyzed both total cellular RNA and synthetic small unstructured RNAs. IMP-1 also hydrolyzed pre-tRNA, but its cleavage site was different from those of T. maritima tRNase Z and human tRNase Z long form, indicating a key difference in substrate recognition. Single-turnover kinetic assays suggested that substrate-binding affinity of T. maritima tRNase Z is much higher than that of IMP-1.
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Affiliation(s)
- Yoshiki Kato
- Department of Applied Life Sciences, Niigata University of Pharmacy and Applied Life Sciences, Niigata, Japan
| | - Masayuki Takahashi
- Research Institute for Healthy Living, Niigata University of Pharmacy and Applied Life Sciences, Niigata, Japan
| | - Mineaki Seki
- Research Institute for Healthy Living, Niigata University of Pharmacy and Applied Life Sciences, Niigata, Japan
| | - Masayuki Nashimoto
- Research Institute for Healthy Living, Niigata University of Pharmacy and Applied Life Sciences, Niigata, Japan
| | - Akiko Shimizu-Ibuka
- Department of Applied Life Sciences, Niigata University of Pharmacy and Applied Life Sciences, Niigata, Japan
- * E-mail:
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Wang X, Gu X, Li J, Yue L, Li D, Dong X. Characterization of the Methanomicrobial Archaeal RNase Zs for Processing the CCA-Containing tRNA Precursors. Front Microbiol 2020; 11:1851. [PMID: 32982996 PMCID: PMC7479834 DOI: 10.3389/fmicb.2020.01851] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Accepted: 07/15/2020] [Indexed: 01/19/2023] Open
Abstract
RNase Z is a widely distributed and usually essential endoribonuclease involved in the 3′-end maturation of transfer RNAs (tRNAs). A CCA triplet that is needed for tRNA aminoacylation in protein translation is added by a nucleotidyl-transferase after the 3′-end processing by RNase Z. However, a considerable proportion of the archaeal pre-tRNAs genetically encode a CCA motif, while the enzymatic characteristics of the archaeal RNase (aRNase) Zs in processing CCA-containing pre-tRNAs remain unclear. This study intensively characterized two methanomicrobial aRNase Zs, the Methanolobus psychrophilus mpy-RNase Z and the Methanococcus maripaludis mmp-RNase Z, particularly focusing on the properties of processing the CCA-containing pre-tRNAs, and in parallel comparison with a bacterial bsu-RNase Z from Bacillus subtilis. Kinetic analysis found that Co2+ supplementation enhanced the cleavage efficiency of mpy-RNase Z, mmp-RNase Z, and bsu-RNase Z for 1400-, 2990-, and 34-fold, respectively, and Co2+ is even more indispensable to the aRNase Zs than to bsu-RNase Z. Mg2+ also elevated the initial cleavage velocity (V0) of bsu-RNase Z for 60.5-fold. The two aRNase Zs exhibited indiscriminate efficiencies in processing CCA-containing vs. CCA-less pre-tRNAs. However, V0 of bsu-RNase Z was markedly reduced for 1520-fold by the CCA motif present in pre-tRNAs under Mg2+ supplementation, but only 5.8-fold reduced under Co2+ supplementation, suggesting Co2+ could ameliorate the CCA motif inhibition on bsu-RNase Z. By 3′-RACE, we determined that the aRNase Zs cleaved just downstream the discriminator nucleotide and the CCA triplet in CCA-less and CCA-containing pre-tRNAs, thus exposing the 3′-end for linking CCA and the genetically encoded CCA triplet, respectively. The aRNase Zs, but not bsu-RNase Z, were also able to process the intron-embedded archaeal pre-tRNAs, and even process pre-tRNAs that lack the D, T, or anticodon arm, but strictly required the acceptor stem. In summary, the two methanomicrobial aRNase Zs use cobalt as a metal ligand and process a broad spectrum of pre-tRNAs, and the characteristics would extend our understandings on aRNase Zs.
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Affiliation(s)
- Xiaoyan Wang
- Department of Biochemistry and Molecular Biology, Institute of Basic Medical Sciences, College of Basic Medicine, Hubei University of Medicine, Shiyan, China.,Hubei Key Laboratory of Embryonic Stem Cell Research, Hubei University of Medicine, Shiyan, China
| | - Xien Gu
- Department of Biochemistry and Molecular Biology, Institute of Basic Medical Sciences, College of Basic Medicine, Hubei University of Medicine, Shiyan, China
| | - Jie Li
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Lei Yue
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.,State Key Laboratory of Microbial Resources, University of Chinese Academy of Sciences, Beijing, China
| | - Defeng Li
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Xiuzhu Dong
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.,State Key Laboratory of Microbial Resources, University of Chinese Academy of Sciences, Beijing, China
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Lee JH, Takahashi M, Jeon JH, Kang LW, Seki M, Park KS, Hong MK, Park YS, Kim TY, Karim AM, Lee JH, Nashimoto M, Lee SH. Dual activity of PNGM-1 pinpoints the evolutionary origin of subclass B3 metallo- β-lactamases: a molecular and evolutionary study. Emerg Microbes Infect 2019; 8:1688-1700. [PMID: 31749408 PMCID: PMC6882493 DOI: 10.1080/22221751.2019.1692638] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Resistance to β-lactams is one of the most serious problems associated with Gram-negative infections. β-Lactamases are able to hydrolyze β-lactams such as cephalosporins and/or carbapenems. Evolutionary origin of metallo-β-lactamases (MBLs), conferring critical antibiotic resistance threats, remains unknown. We discovered PNGM-1, the novel subclass B3 MBL, in deep-sea sediments that predate the antibiotic era. Here, our phylogenetic analysis suggests that PNGM-1 yields insights into the evolutionary origin of subclass B3 MBLs. We reveal the structural similarities between tRNase Zs and PNGM-1, and demonstrate that PNGM-1 has both MBL and tRNase Z activities, suggesting that PNGM-1 is thought to have evolved from a tRNase Z. We also show kinetic and structural comparisons between PNGM-1 and other proteins including subclass B3 MBLs and tRNase Zs. These comparisons revealed that the B3 MBL activity of PNGM-1 is a promiscuous activity and subclass B3 MBLs are thought to have evolved through PNGM-1 activity.
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Affiliation(s)
- Jung Hun Lee
- National Leading Research Laboratory of Drug Resistance Proteomics, Department of Biological Sciences, Myongji University, Yongin, Republic of Korea
| | - Masayuki Takahashi
- Research Institute for Healthy Living, Niigata University of Pharmacy and Applied Life Sciences, Niigata, Japan
| | - Jeong Ho Jeon
- National Leading Research Laboratory of Drug Resistance Proteomics, Department of Biological Sciences, Myongji University, Yongin, Republic of Korea
| | - Lin-Woo Kang
- Department of Biological Sciences, Konkuk University, Seoul, Republic of Korea
| | - Mineaki Seki
- Research Institute for Healthy Living, Niigata University of Pharmacy and Applied Life Sciences, Niigata, Japan
| | - Kwang Seung Park
- National Leading Research Laboratory of Drug Resistance Proteomics, Department of Biological Sciences, Myongji University, Yongin, Republic of Korea
| | - Myoung-Ki Hong
- Department of Biological Sciences, Konkuk University, Seoul, Republic of Korea
| | - Yoon Sik Park
- Department of Biological Sciences, Konkuk University, Seoul, Republic of Korea
| | - Tae Yeong Kim
- National Leading Research Laboratory of Drug Resistance Proteomics, Department of Biological Sciences, Myongji University, Yongin, Republic of Korea
| | - Asad Mustafa Karim
- National Leading Research Laboratory of Drug Resistance Proteomics, Department of Biological Sciences, Myongji University, Yongin, Republic of Korea
| | - Jung-Hyun Lee
- Marine Biotechnology Research Center, Korea Institute of Ocean Science & Technology, Busan, Republic of Korea
| | - Masayuki Nashimoto
- Research Institute for Healthy Living, Niigata University of Pharmacy and Applied Life Sciences, Niigata, Japan
| | - Sang Hee Lee
- National Leading Research Laboratory of Drug Resistance Proteomics, Department of Biological Sciences, Myongji University, Yongin, Republic of Korea
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Bechhofer DH, Deutscher MP. Bacterial ribonucleases and their roles in RNA metabolism. Crit Rev Biochem Mol Biol 2019; 54:242-300. [PMID: 31464530 PMCID: PMC6776250 DOI: 10.1080/10409238.2019.1651816] [Citation(s) in RCA: 96] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 07/22/2019] [Accepted: 07/31/2019] [Indexed: 12/16/2022]
Abstract
Ribonucleases (RNases) are mediators in most reactions of RNA metabolism. In recent years, there has been a surge of new information about RNases and the roles they play in cell physiology. In this review, a detailed description of bacterial RNases is presented, focusing primarily on those from Escherichia coli and Bacillus subtilis, the model Gram-negative and Gram-positive organisms, from which most of our current knowledge has been derived. Information from other organisms is also included, where relevant. In an extensive catalog of the known bacterial RNases, their structure, mechanism of action, physiological roles, genetics, and possible regulation are described. The RNase complement of E. coli and B. subtilis is compared, emphasizing the similarities, but especially the differences, between the two. Included are figures showing the three major RNA metabolic pathways in E. coli and B. subtilis and highlighting specific steps in each of the pathways catalyzed by the different RNases. This compilation of the currently available knowledge about bacterial RNases will be a useful tool for workers in the RNA field and for others interested in learning about this area.
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Affiliation(s)
- David H. Bechhofer
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Murray P. Deutscher
- Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, Miami, FL, USA
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7
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Wen J, Wang L, Wang J, Zeng Y, Xu Y, Li S. The transcription factor OsbHLH138 regulates thermosensitive genic male sterility in rice via activation of TMS5. TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 2019; 132:1721-1732. [PMID: 30778635 DOI: 10.1007/s00122-019-03310-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2018] [Accepted: 02/08/2019] [Indexed: 06/09/2023]
Abstract
Thermosensitive genic male sterile (TGMS) lines favored heterosis exploitation in two-line hybrid rice. TMS5, a member of RNase Z cleavages the UbL40 mRNAs, plays an important role in two-line hybrid rice. Here, we identified a new TGMS mutant 93-11s, which lost two amino acids in the first exon of TMS5 gene and caused thermosensitive genic male sterility in rice. The tms5-2 cannot process mRNAs of the ubiquitin fusion ribosomal protein L40 (UbL40) and hence cause the mRNAs accumulation in restrictive temperature. Further, we identified a nucleus-localized bHLH transcription factor OsbHLH138, which can form the basic helix-loop-helix structure and bind the core region of tms5-2 promoter sequences by bHLH domain, and activate expression of tms5-2 by the acidic amino acid-rich domain. These results indicate a novel mechanism for the tms5-2 regulating thermosensitive male sterility of rice. By altering expression of OsbHLH138, we can regulate the expression level of TMS5 and the accumulation of UbL40 mRNAs to command the male fertility in different temperatures. The identification of OsbHLH138 provides breeders a new choice for development of TGMS rice lines, which will favor the sustainable development of two-line hybrid rice.
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Affiliation(s)
- Jianyu Wen
- State Key Laboratory of Hybrid Rice, Key Laboratory for Research and Utilization of Heterosis in Indica Rice of Ministry of Agriculture, Engineering Research Center for Plant Biotechnology and Germplasm Utilization of Ministry of Education, College of Life Science, Wuhan University, Wuhan, 430072, China
| | - Liuting Wang
- State Key Laboratory of Hybrid Rice, Key Laboratory for Research and Utilization of Heterosis in Indica Rice of Ministry of Agriculture, Engineering Research Center for Plant Biotechnology and Germplasm Utilization of Ministry of Education, College of Life Science, Wuhan University, Wuhan, 430072, China
| | - Jie Wang
- State Key Laboratory of Hybrid Rice, Key Laboratory for Research and Utilization of Heterosis in Indica Rice of Ministry of Agriculture, Engineering Research Center for Plant Biotechnology and Germplasm Utilization of Ministry of Education, College of Life Science, Wuhan University, Wuhan, 430072, China
| | - Yafei Zeng
- State Key Laboratory of Hybrid Rice, Key Laboratory for Research and Utilization of Heterosis in Indica Rice of Ministry of Agriculture, Engineering Research Center for Plant Biotechnology and Germplasm Utilization of Ministry of Education, College of Life Science, Wuhan University, Wuhan, 430072, China
| | - Yanghong Xu
- State Key Laboratory of Hybrid Rice, Key Laboratory for Research and Utilization of Heterosis in Indica Rice of Ministry of Agriculture, Engineering Research Center for Plant Biotechnology and Germplasm Utilization of Ministry of Education, College of Life Science, Wuhan University, Wuhan, 430072, China
| | - Shaoqing Li
- State Key Laboratory of Hybrid Rice, Key Laboratory for Research and Utilization of Heterosis in Indica Rice of Ministry of Agriculture, Engineering Research Center for Plant Biotechnology and Germplasm Utilization of Ministry of Education, College of Life Science, Wuhan University, Wuhan, 430072, China.
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Clouet-d'Orval B, Batista M, Bouvier M, Quentin Y, Fichant G, Marchfelder A, Maier LK. Insights into RNA-processing pathways and associated RNA-degrading enzymes in Archaea. FEMS Microbiol Rev 2018; 42:579-613. [PMID: 29684129 DOI: 10.1093/femsre/fuy016] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Accepted: 04/17/2018] [Indexed: 12/20/2022] Open
Abstract
RNA-processing pathways are at the centre of regulation of gene expression. All RNA transcripts undergo multiple maturation steps in addition to covalent chemical modifications to become functional in the cell. This includes destroying unnecessary or defective cellular RNAs. In Archaea, information on mechanisms by which RNA species reach their mature forms and associated RNA-modifying enzymes are still fragmentary. To date, most archaeal actors and pathways have been proposed in light of information gathered from Bacteria and Eukarya. In this context, this review provides a state of the art overview of archaeal endoribonucleases and exoribonucleases that cleave and trim RNA species and also of the key small archaeal proteins that bind RNAs. Furthermore, synthetic up-to-date views of processing and biogenesis pathways of archaeal transfer and ribosomal RNAs as well as of maturation of stable small non-coding RNAs such as CRISPR RNAs, small C/D and H/ACA box guide RNAs, and other emerging classes of small RNAs are described. Finally, prospective post-transcriptional mechanisms to control archaeal messenger RNA quality and quantity are discussed.
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Affiliation(s)
- Béatrice Clouet-d'Orval
- Laboratoire de Microbiologie et de Génétique Moléculaires (LMGM), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, 31062 Toulouse, France
| | - Manon Batista
- Laboratoire de Microbiologie et de Génétique Moléculaires (LMGM), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, 31062 Toulouse, France
| | - Marie Bouvier
- Laboratoire de Microbiologie et de Génétique Moléculaires (LMGM), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, 31062 Toulouse, France
| | - Yves Quentin
- Laboratoire de Microbiologie et de Génétique Moléculaires (LMGM), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, 31062 Toulouse, France
| | - Gwennaele Fichant
- Laboratoire de Microbiologie et de Génétique Moléculaires (LMGM), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, 31062 Toulouse, France
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A tRNA's fate is decided at its 3' end: Collaborative actions of CCA-adding enzyme and RNases involved in tRNA processing and degradation. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2018; 1861:433-441. [PMID: 29374586 DOI: 10.1016/j.bbagrm.2018.01.012] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Revised: 01/15/2018] [Accepted: 01/19/2018] [Indexed: 02/07/2023]
Abstract
tRNAs are key players in translation and are additionally involved in a wide range of distinct cellular processes. The vital importance of tRNAs becomes evident in numerous diseases that are linked to defective tRNA molecules. It is therefore not surprising that the structural intactness of tRNAs is continuously scrutinized and defective tRNAs are eliminated. In this process, erroneous tRNAs are tagged with single-stranded RNA sequences that are recognized by degrading exonucleases. Recent discoveries have revealed that the CCA-adding enzyme - actually responsible for the de novo synthesis of the 3'-CCA end - plays an indispensable role in tRNA quality control by incorporating a second CCA triplet that is recognized as a degradation tag. In this review, we give an update on the latest findings regarding tRNA quality control that turns out to represent an interplay of the CCA-adding enzyme and RNases involved in tRNA degradation and maturation. In particular, the RNase-induced turnover of the CCA end is now recognized as a trigger for the CCA-adding enzyme to repeatedly scrutinize the structural intactness of a tRNA. This article is part of a Special Issue entitled: SI: Regulation of tRNA synthesis and modification in physiological conditions and disease edited by Dr. Boguta Magdalena.
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10
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Matelska D, Steczkiewicz K, Ginalski K. Comprehensive classification of the PIN domain-like superfamily. Nucleic Acids Res 2017; 45:6995-7020. [PMID: 28575517 PMCID: PMC5499597 DOI: 10.1093/nar/gkx494] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Accepted: 05/24/2017] [Indexed: 12/21/2022] Open
Abstract
PIN-like domains constitute a widespread superfamily of nucleases, diverse in terms of the reaction mechanism, substrate specificity, biological function and taxonomic distribution. Proteins with PIN-like domains are involved in central cellular processes, such as DNA replication and repair, mRNA degradation, transcription regulation and ncRNA maturation. In this work, we identify and classify the most complete set of PIN-like domains to provide the first comprehensive analysis of sequence–structure–function relationships within the whole PIN domain-like superfamily. Transitive sequence searches using highly sensitive methods for remote homology detection led to the identification of several new families, including representatives of Pfam (DUF1308, DUF4935) and CDD (COG2454), and 23 other families not classified in the public domain databases. Further sequence clustering revealed relationships between individual sequence clusters and showed heterogeneity within some families, suggesting a possible functional divergence. With five structural groups, 70 defined clusters, over 100,000 proteins, and broad biological functions, the PIN domain-like superfamily constitutes one of the largest and most diverse nuclease superfamilies. Detailed analyses of sequences and structures, domain architectures, and genomic contexts allowed us to predict biological function of several new families, including new toxin-antitoxin components, proteins involved in tRNA/rRNA maturation and transcription/translation regulation.
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Affiliation(s)
- Dorota Matelska
- University of Warsaw, CeNT, Laboratory of Bioinformatics and Systems Biology, Zwirki i Wigury 93, 02-089 Warsaw, Poland
| | - Kamil Steczkiewicz
- University of Warsaw, CeNT, Laboratory of Bioinformatics and Systems Biology, Zwirki i Wigury 93, 02-089 Warsaw, Poland
| | - Krzysztof Ginalski
- University of Warsaw, CeNT, Laboratory of Bioinformatics and Systems Biology, Zwirki i Wigury 93, 02-089 Warsaw, Poland
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Abstract
The removal of transcriptional 5' and 3' extensions is an essential step in tRNA biogenesis. In some bacteria, tRNA 5'- and 3'-end maturation require no further steps, because all their genes encode the full tRNA sequence. Often however, the ends are incomplete, and additional maturation, repair or editing steps are needed. In all Eukarya, but also many Archaea and Bacteria, e.g., the universal 3'-terminal CCA is not encoded and has to be added by the CCA-adding enzyme. Apart from such widespread "repair/maturation" processes, tRNA genes in some cases apparently cannot give rise to intact, functional tRNA molecules without further, more specific end repair or editing. Interestingly, the responsible enzymes as far as identified appear to be polymerases usually involved in regular tRNA repair after damage. Alternatively, enzymes are recruited from other non-tRNA pathways; e.g., in animal mitochondria, poly(A) polymerase plays a crucial role in the 3'-end repair/editing of tRNAs. While these repair/editing pathways apparently allowed peculiar tRNA-gene overlaps or mismatching mutations in the acceptor stem to become genetically fixed in some present-day organisms, they may have also driven some global changes in tRNA maturation on a greater evolutionary scale.
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Affiliation(s)
- Christiane Rammelt
- a Institute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg , Halle , Germany
| | - Walter Rossmanith
- b Center for Anatomy & Cell Biology, Medical University of Vienna , Vienna , Austria
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12
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RNase ZS1 processes UbL40 mRNAs and controls thermosensitive genic male sterility in rice. Nat Commun 2014; 5:4884. [DOI: 10.1038/ncomms5884] [Citation(s) in RCA: 141] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2014] [Accepted: 08/03/2014] [Indexed: 11/08/2022] Open
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Long T, Guo D, He D, Shen W, Li X. The tRNA 3'-end processing enzyme tRNase Z2 contributes to chloroplast biogenesis in rice. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2013; 55:1104-18. [PMID: 24034348 DOI: 10.1111/jipb.12102] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2013] [Accepted: 08/19/2013] [Indexed: 05/08/2023]
Abstract
tRNase Z (TRZ) is a ubiquitous endonuclease that removes the 3'-trailer from precursor tRNAs during maturation. In yeast and animals, TRZ regulates the cell cycle via its (t)RNA processing activity; however, its physiological function in higher plants has not been well characterized. This study describes the identification of a rice (Oryza sativa) TRZ2 mutant; plants homozygous for the osatrz2 mutation were albinos with deficient chlorophyll content. A microscopic analysis of the mutant plants revealed that the transition of proplastids to chloroplasts was arrested at an early stage, and the number and size of the plastids in callus cells was substantially decreased. A genetic complementation test and an RNA interference analysis confirmed that disruption of OsaTRZ2 was responsible for the mutant phenotype. OsaTRZ2 is expressed in all rice tissues, but is preferentially expressed in leaves, sheathes, and calli. OsaTRZ2 was subcellularly localized in chloroplasts, and displayed tRNA 3'-end processing activity in both in vitro and in vivo assays. In the osatrz2 mutants, transcription of plastid-encoded and nucleus-encoded RNA polymerases was severely reduced and moderately increased, respectively. These results suggest that the tRNA 3' processing activity of OsaTRZ2 contributes to chloroplast biogenesis.
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Affiliation(s)
- Tuan Long
- National Key Laboratory of Crop Genetic Improvement and National Center of Plant Gene Research (Wuhan), Huazhong Agricultural University, Wuhan, 430070, China
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15
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Dutta T, Malhotra A, Deutscher MP. How a CCA sequence protects mature tRNAs and tRNA precursors from action of the processing enzyme RNase BN/RNase Z. J Biol Chem 2013; 288:30636-30644. [PMID: 24022488 DOI: 10.1074/jbc.m113.514570] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In many organisms, 3' maturation of tRNAs is catalyzed by the endoribonuclease, RNase BN/RNase Z, which cleaves after the discriminator nucleotide to generate a substrate for addition of the universal CCA sequence. However, tRNAs or tRNA precursors that already contain a CCA sequence are not cleaved, thereby avoiding a futile cycle of removal and readdition of these essential residues. We show here that the adjacent C residues of the CCA sequence and an Arg residue within a highly conserved sequence motif in the channel leading to the RNase catalytic site are both required for the protective effect of the CCA sequence. When both of these determinants are present, CCA-containing RNAs in the channel are unable to move into the catalytic site; however, substitution of either of the C residues by A or U or mutation of Arg(274) to Ala allows RNA movement and catalysis to proceed. These data define a novel mechanism for how tRNAs are protected against the promiscuous action of a processing enzyme.
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Affiliation(s)
- Tanmay Dutta
- From the Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, Miami, Florida 33136
| | - Arun Malhotra
- From the Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, Miami, Florida 33136
| | - Murray P Deutscher
- From the Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, Miami, Florida 33136.
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Pellegrini O, Li de la Sierra-Gallay I, Piton J, Gilet L, Condon C. Activation of tRNA Maturation by Downstream Uracil Residues in B. subtilis. Structure 2012; 20:1769-77. [PMID: 22940585 DOI: 10.1016/j.str.2012.08.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2012] [Revised: 07/30/2012] [Accepted: 08/05/2012] [Indexed: 11/16/2022]
Affiliation(s)
- Olivier Pellegrini
- CNRS UPR 9073 (affiliated with Université Paris Diderot, Sorbonne Paris Cité), Institut de Biologie Physico-Chimique, 13 rue Pierre et Marie Curie, 75005 Paris, France
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17
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Dutta T, Malhotra A, Deutscher MP. Exoribonuclease and endoribonuclease activities of RNase BN/RNase Z both function in vivo. J Biol Chem 2012; 287:35747-35755. [PMID: 22893707 DOI: 10.1074/jbc.m112.407403] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Escherichia coli RNase BN, a member of the RNase Z family of endoribonucleases, differs from other family members in that it also can act as an exoribonuclease in vitro. Here, we examine whether this activity of RNase BN also functions in vivo. Comparison of the x-ray structure of RNase BN with that of Bacillus subtilis RNase Z, which lacks exoribonuclease activity, revealed that RNase BN has a narrower and more rigid channel downstream of the catalytic site. We hypothesized that this difference in the putative RNA exit channel might be responsible for the acquisition of exoribonuclease activity by RNase BN. Accordingly, we generated several mutant RNase BN proteins in which residues within a loop in this channel were converted to the corresponding residues present in B. subtilis RNase Z, thus widening the channel and increasing its flexibility. The resulting mutant RNase BN proteins had reduced or were essentially devoid of exoribonuclease activity in vitro. Substitution of one mutant rbn gene (P142G) for wild type rbn in the E. coli chromosome revealed that the exoribonuclease activity of RNase BN is not required for maturation of phage T4 tRNA precursors, a known specific function of this RNase. On the other hand, removal of the exoribonuclease activity of RNase BN in a cell lacking other processing RNases leads to slower growth and affects maturation of multiple tRNA precursors. These findings help explain how RNase BN can act as both an exo- and an endoribonuclease and also demonstrate that its exoribonuclease activity is capable of functioning in vivo, thus widening the potential role of this enzyme in E. coli.
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Affiliation(s)
- Tanmay Dutta
- Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, Miami, Florida 33136
| | - Arun Malhotra
- Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, Miami, Florida 33136
| | - Murray P Deutscher
- Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, Miami, Florida 33136.
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Alluri RK, Li Z. Novel one-step mechanism for tRNA 3'-end maturation by the exoribonuclease RNase R of Mycoplasma genitalium. J Biol Chem 2012; 287:23427-33. [PMID: 22605341 DOI: 10.1074/jbc.m111.324970] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Mycoplasma genitalium is expected to metabolize RNA using unique pathways because its minimal genome encodes very few ribonucleases. In this work, we report that the only exoribonuclease identified in M. genitalium, RNase R, is able to remove tRNA 3'-trailers and generate mature 3'-ends. Several sequence and structural features of a tRNA precursor determine its precise processing at the 3'-end by RNase R in a purified system. The aminoacyl-acceptor stem plays a major role in stopping RNase R digestion at the mature 3'-end. Disruption of the stem causes partial or complete degradation of the pre-tRNA by RNase R, whereas extension of the stem results in the formation of a product terminating downstream at the new mature 3'-end. In addition, the 3'-terminal CCA sequence and the discriminator residue influence the ability of RNase R to stop at the mature 3'-end. RNase R-mediated generation of the mature 3'-end prefers a sequence of RCCN at the 3' terminus of tRNA. Variations of this sequence may cause RNase R to trim further and remove terminal CA residues from the mature 3'-end. Therefore, M. genitalium RNase R can precisely remove the 3'-trailer of a tRNA precursor by recognizing features in the terminal domains of tRNA, a process requiring multiple RNases in most bacteria.
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Affiliation(s)
- Ravi K Alluri
- Department of Biomedical Science, Charles E Schmidt College of Medicine, Florida Atlantic University, Boca Raton, Florida 33431, USA
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Fan L, Wang Z, Liu J, Guo W, Yan J, Huang Y. A survey of green plant tRNA 3'-end processing enzyme tRNase Zs, homologs of the candidate prostate cancer susceptibility protein ELAC2. BMC Evol Biol 2011; 11:219. [PMID: 21781332 PMCID: PMC3161902 DOI: 10.1186/1471-2148-11-219] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2011] [Accepted: 07/23/2011] [Indexed: 11/10/2022] Open
Abstract
Background tRNase Z removes the 3'-trailer sequences from precursor tRNAs, which is an essential step preceding the addition of the CCA sequence. tRNase Z exists in the short (tRNase ZS) and long (tRNase ZL) forms. Based on the sequence characteristics, they can be divided into two major types: bacterial-type tRNase ZS and eukaryotic-type tRNase ZL, and one minor type, Thermotoga maritima (TM)-type tRNase ZS. The number of tRNase Zs is highly variable, with the largest number being identified experimentally in the flowering plant Arabidopsis thaliana. It is unknown whether multiple tRNase Zs found in A. thaliana is common to the plant kingdom. Also unknown is the extent of sequence and structural conservation among tRNase Zs from the plant kingdom. Results We report the identification and analysis of candidate tRNase Zs in 27 fully sequenced genomes of green plants, the great majority of which are flowering plants. It appears that green plants contain multiple distinct tRNase Zs predicted to reside in different subcellular compartments. Furthermore, while the bacterial-type tRNase ZSs are present only in basal land plants and green algae, the TM-type tRNase ZSs are widespread in green plants. The protein sequences of the TM-type tRNase ZSs identified in green plants are similar to those of the bacterial-type tRNase ZSs but have distinct features, including the TM-type flexible arm, the variant catalytic HEAT and HST motifs, and a lack of the PxKxRN motif involved in CCA anti-determination (inhibition of tRNase Z activity by CCA), which prevents tRNase Z cleavage of mature tRNAs. Examination of flowering plant chloroplast tRNA genes reveals that many of these genes encode partial CCA sequences. Based on our results and previous studies, we predict that the plant TM-type tRNase ZSs may not recognize the CCA sequence as an anti-determinant. Conclusions Our findings substantially expand the current repertoire of the TM-type tRNase ZSs and hint at the possibility that these proteins may have been selected for their ability to process chloroplast pre-tRNAs with whole or partial CCA sequences. Our results also support the coevolution of tRNase Zs and tRNA 3'-trailer sequences in plants.
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Affiliation(s)
- Lijuan Fan
- Laboratory of Yeast Genetics and Molecular Biology, School of Life Sciences, Nanjing Normal University, 1 Wenyuan Road, Nanjing 210046, China
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The fission yeast Schizosaccharomyces pombe has two distinct tRNase ZLs encoded by two different genes and differentially targeted to the nucleus and mitochondria. Biochem J 2011; 435:103-11. [DOI: 10.1042/bj20101619] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
tRNase Z is the endonuclease that is involved in tRNA 3′-end maturation by removal of the 3′-trailer sequences from tRNA precursors. Most eukaryotes examined to date, including the budding yeast Saccharomyces cerevisiae and humans, have a single long form of tRNase Z (tRNase ZL). In contrast, the fission yeast Schizosaccharomyces pombe contains two candidate tRNase ZLs encoded by the essential genes sptrz1+ and sptrz2+. In the present study, we have expressed recombinant SpTrz1p and SpTrz2p in S. pombe. Both recombinant proteins possess precursor tRNA 3′-endonucleolytic activity in vitro. SpTrz1p localizes to the nucleus and has a simian virus 40 NLS (nuclear localization signal)-like NLS at its N-terminus, which contains four consecutive arginine and lysine residues between residues 208 and 211 that are critical for the NLS function. In contrast, SpTrz2p is a mitochondrial protein with an N-terminal MTS (mitochondrial-targeting signal). High-level overexpression of sptrz1+ has no detectable phenotypes. In contrast, strong overexpression of sptrz2+ is lethal in wild-type cells and results in morphological abnormalities, including swollen and round cells, demonstrating that the correct expression level of sptrz2+ is critical. The present study provides evidence for partitioning of tRNase Z function between two different proteins in S. pombe, although we cannot rule out specialized functions for each protein.
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The putative hydrolase YycJ (WalJ) affects the coordination of cell division with DNA replication in Bacillus subtilis and may play a conserved role in cell wall metabolism. J Bacteriol 2010; 193:896-908. [PMID: 21169496 DOI: 10.1128/jb.00594-10] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bacteria must accurately replicate and segregate their genetic information to ensure the production of viable daughter cells. The high fidelity of chromosome partitioning is achieved through mechanisms that coordinate cell division with DNA replication. We report that YycJ (WalJ), a predicted member of the metallo-β-lactamase superfamily found in most low-G+C Gram-positive bacteria, contributes to the fidelity of cell division in Bacillus subtilis. B. subtilis ΔwalJ (ΔwalJ(Bsu)) mutants divide over unsegregated chromosomes more frequently than wild-type cells, and this phenotype is exacerbated when DNA replication is inhibited. Two lines of evidence suggest that WalJ(Bsu) and its ortholog in the Gram-positive pathogen Streptococcus pneumoniae, WalJ(Spn) (VicX), play a role in cell wall metabolism: (i) strains of B. subtilis and S. pneumoniae lacking walJ exhibit increased sensitivity to a narrow spectrum of cephalosporin antibiotics, and (ii) reducing the expression of a two-component system that regulates genes involved in cell wall metabolism, WalRK (YycFG), renders walJ essential for growth in B. subtilis, as observed previously with S. pneumoniae. Together, these results suggest that the enzymatic activity of WalJ directly or indirectly affects cell wall metabolism and is required for accurate coordination of cell division with DNA replication.
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Nathania L, Nicholson AW. Thermotoga maritima ribonuclease III. Characterization of thermostable biochemical behavior and analysis of conserved base pairs that function as reactivity epitopes for the Thermotoga 23S rRNA precursor. Biochemistry 2010; 49:7164-78. [PMID: 20677811 DOI: 10.1021/bi100930u] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The cleavage of double-stranded (ds) RNA by ribonuclease III is a conserved early step in bacterial rRNA maturation. Studies on the mechanism of dsRNA cleavage by RNase III have focused mainly on the enzymes from mesophiles such as Escherichia coli. In contrast, neither the catalytic properties of extremophile RNases III nor the structures and reactivities of their cognate substrates have been described. The biochemical behavior of RNase III of the hyperthermophilic bacterium Thermotoga maritima was analyzed using purified recombinant enzyme. T. maritima (Tm) RNase III catalytic activity exhibits a broad optimal temperature range of approximately 40-70 degrees C, with significant activity at 95 degrees C. Tm-RNase III cleavage of substrate is optimally supported by Mg(2+) at >or=1 mM concentrations. Mn(2+), Co(2+), and Ni(2+) also support activity but with reduced efficiencies. The enzyme functions optimally at pH 8 and approximately 50-80 mM salt concentrations. Small RNA hairpins that incorporate the 16S and 23S pre-rRNA stem sequences are efficiently cleaved by Tm-RNase III at sites that are consistent with production in vivo of the immediate precursors to the mature rRNAs. Analysis of pre-23S substrate variants reveals a dependence of reactivity on the base-pair (bp) sequence in the proximal box (pb), a site of protein contact that functions as a positive recognition determinant for Escherichia coli (Ec) RNase III substrates. The dependence of reactivity on the pb sequence is similar to that observed with Ec-RNase III substrates. In fact, Tm-RNase III cleaves an Ec-RNase III substrate with identical specificity and is inhibited by antideterminant bp that also inhibit Ec-RNase III. These results indicate the conservation, across a broad phylogenetic distance, of positive and negative determinants of reactivity of bacterial RNase III substrates.
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Affiliation(s)
- Lilian Nathania
- Department of Chemistry, Temple University, Philadelphia, Pennsylvania 19122, USA
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24
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Abstract
Nucleases cleave the phosphodiester bonds of nucleic acids and may be endo or exo, DNase or RNase, topoisomerases, recombinases, ribozymes, or RNA splicing enzymes. In this review, I survey nuclease activities with known structures and catalytic machinery and classify them by reaction mechanism and metal-ion dependence and by their biological function ranging from DNA replication, recombination, repair, RNA maturation, processing, interference, to defense, nutrient regeneration or cell death. Several general principles emerge from this analysis. There is little correlation between catalytic mechanism and biological function. A single catalytic mechanism can be adapted in a variety of reactions and biological pathways. Conversely, a single biological process can often be accomplished by multiple tertiary and quaternary folds and by more than one catalytic mechanism. Two-metal-ion-dependent nucleases comprise the largest number of different tertiary folds and mediate the most diverse set of biological functions. Metal-ion-dependent cleavage is exclusively associated with exonucleases producing mononucleotides and endonucleases that cleave double- or single-stranded substrates in helical and base-stacked conformations. All metal-ion-independent RNases generate 2',3'-cyclic phosphate products, and all metal-ion-independent DNases form phospho-protein intermediates. I also find several previously unnoted relationships between different nucleases and shared catalytic configurations.
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25
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Abstract
tRNA biology has come of age, revealing an unprecedented level of understanding and many unexpected discoveries along the way. This review highlights new findings on the diverse pathways of tRNA maturation, and on the formation and function of a number of modifications. Topics of special focus include the regulation of tRNA biosynthesis, quality control tRNA turnover mechanisms, widespread tRNA cleavage pathways activated in response to stress and other growth conditions, emerging evidence of signaling pathways involving tRNA and cleavage fragments, and the sophisticated intracellular tRNA trafficking that occurs during and after biosynthesis.
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Affiliation(s)
- Eric M Phizicky
- Department of Biochemistry and Biophysics, Center for RNA Biology, University of Rochester School of Medicine, Rochester, New York 14642, USA.
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Zhao W, Yu H, Li S, Huang Y. Identification and analysis of candidate fungal tRNA 3'-end processing endonucleases tRNase Zs, homologs of the putative prostate cancer susceptibility protein ELAC2. BMC Evol Biol 2010; 10:272. [PMID: 20819227 PMCID: PMC2942849 DOI: 10.1186/1471-2148-10-272] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2010] [Accepted: 09/06/2010] [Indexed: 01/11/2023] Open
Abstract
BACKGROUND tRNase Z is the endonuclease that is responsible for the 3'-end processing of tRNA precursors, a process essential for tRNA 3'-CCA addition and subsequent tRNA aminoacylation. Based on their sizes, tRNase Zs can be divided into the long (tRNase ZL) and short (tRNase ZS) forms. tRNase ZL is thought to have arisen from a tandem gene duplication of tRNase ZS with further sequence divergence. The species distribution of tRNase Z is complex. Fungi represent an evolutionarily diverse group of eukaryotes. The recent proliferation of fungal genome sequences provides an opportunity to explore the structural and functional diversity of eukaryotic tRNase Zs. RESULTS We report a survey and analysis of candidate tRNase Zs in 84 completed fungal genomes, spanning a broad diversity of fungi. We find that tRNase ZL is present in all fungi we have examined, whereas tRNase ZS exists only in the fungal phyla Basidiomycota, Chytridiomycota and Zygomycota. Furthermore, we find that unlike the Pezizomycotina and Saccharomycotina, which contain a single tRNase ZL, Schizosaccharomyces fission yeasts (Taphrinomycotina) contain two tRNase ZLs encoded by two different tRNase ZL genes. These two tRNase ZLs are most likely localized to the nucleus and mitochondria, respectively, suggesting partitioning of tRNase Z function between two different tRNase ZLs in fission yeasts. The fungal tRNase Z phylogeny suggests that tRNase ZSs are ancestral to tRNase ZLs. Additionally, the evolutionary relationship of fungal tRNase ZLs is generally consistent with known phylogenetic relationships among the fungal species and supports tRNase ZL gene duplication in certain fungal taxa, including Schizosaccharomyces fission yeasts. Analysis of tRNase Z protein sequences reveals putative atypical substrate binding domains in most fungal tRNase ZSs and in a subset of fungal tRNase ZLs. Finally, we demonstrate the presence of pseudo-substrate recognition and catalytic motifs at the N-terminal halves of tRNase ZLs. CONCLUSIONS This study describes the first comprehensive identification and sequence analysis of candidate fungal tRNase Zs. Our results support the proposal that tRNase ZL has evolved as a result of duplication and diversification of the tRNase ZS gene.
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Affiliation(s)
- Wei Zhao
- Nanjing Engineering and Technology Research Center for Microbiology, Jiangsu Key Laboratory for Biodiversity and Biotechnology, School of Life Sciences, Nanjing Normal University, Nanjing 210046, China
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Dutta T, Deutscher MP. Mode of action of RNase BN/RNase Z on tRNA precursors: RNase BN does not remove the CCA sequence from tRNA. J Biol Chem 2010; 285:22874-81. [PMID: 20489203 PMCID: PMC2906279 DOI: 10.1074/jbc.m110.141101] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2010] [Revised: 05/13/2010] [Indexed: 11/06/2022] Open
Abstract
RNase BN, the Escherichia coli homolog of RNase Z, was previously shown to act as both a distributive exoribonuclease and an endoribonuclease on model RNA substrates and to be inhibited by the presence of a 3'-terminal CCA sequence. Here, we examined the mode of action of RNase BN on bacteriophage and bacterial tRNA precursors, particularly in light of a recent report suggesting that RNase BN removes CCA sequences (Takaku, H., and Nashimoto, M. (2008) Genes Cells 13, 1087-1097). We show that purified RNase BN can process both CCA-less and CCA-containing tRNA precursors. On CCA-less precursors, RNase BN cleaved endonucleolytically after the discriminator nucleotide to allow subsequent CCA addition. On CCA-containing precursors, RNase BN acted as either an exoribonuclease or endoribonuclease depending on the nature of the added divalent cation. Addition of Co(2+) resulted in higher activity and predominantly exoribonucleolytic activity, whereas in the presence of Mg(2+), RNase BN was primarily an endoribonuclease. In no case was any evidence obtained for removal of the CCA sequence. Certain tRNA precursors were extremely poor substrates under any conditions tested. These findings provide important information on the ability of RNase BN to process tRNA precursors and help explain the known physiological properties of this enzyme. In addition, they call into question the removal of CCA sequences by RNase BN.
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Affiliation(s)
- Tanmay Dutta
- From the Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, Miami, Florida 33101
| | - Murray P. Deutscher
- From the Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, Miami, Florida 33101
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28
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Arraiano CM, Andrade JM, Domingues S, Guinote IB, Malecki M, Matos RG, Moreira RN, Pobre V, Reis FP, Saramago M, Silva IJ, Viegas SC. The critical role of RNA processing and degradation in the control of gene expression. FEMS Microbiol Rev 2010; 34:883-923. [PMID: 20659169 DOI: 10.1111/j.1574-6976.2010.00242.x] [Citation(s) in RCA: 254] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
The continuous degradation and synthesis of prokaryotic mRNAs not only give rise to the metabolic changes that are required as cells grow and divide but also rapid adaptation to new environmental conditions. In bacteria, RNAs can be degraded by mechanisms that act independently, but in parallel, and that target different sites with different efficiencies. The accessibility of sites for degradation depends on several factors, including RNA higher-order structure, protection by translating ribosomes and polyadenylation status. Furthermore, RNA degradation mechanisms have shown to be determinant for the post-transcriptional control of gene expression. RNases mediate the processing, decay and quality control of RNA. RNases can be divided into endonucleases that cleave the RNA internally or exonucleases that cleave the RNA from one of the extremities. Just in Escherichia coli there are >20 different RNases. RNase E is a single-strand-specific endonuclease critical for mRNA decay in E. coli. The enzyme interacts with the exonuclease polynucleotide phosphorylase (PNPase), enolase and RNA helicase B (RhlB) to form the degradosome. However, in Bacillus subtilis, this enzyme is absent, but it has other main endonucleases such as RNase J1 and RNase III. RNase III cleaves double-stranded RNA and family members are involved in RNA interference in eukaryotes. RNase II family members are ubiquitous exonucleases, and in eukaryotes, they can act as the catalytic subunit of the exosome. RNases act in different pathways to execute the maturation of rRNAs and tRNAs, and intervene in the decay of many different mRNAs and small noncoding RNAs. In general, RNases act as a global regulatory network extremely important for the regulation of RNA levels.
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Affiliation(s)
- Cecília M Arraiano
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Apartado 127, 2781-901 Oeiras, Portugal.
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29
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Functional conservation of tRNase ZL among Saccharomyces cerevisiae, Schizosaccharomyces pombe and humans. Biochem J 2009; 422:483-92. [PMID: 19555350 DOI: 10.1042/bj20090743] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Although tRNase Z from various organisms was shown to process nuclear tRNA 3' ends in vitro, only a very limited number of studies have reported its in vivo biological functions. tRNase Z is present in a short form, tRNase Z(S), and a long form, tRNase Z(L). Unlike Saccharomyces cerevisiae, which contains one tRNase Z(L) gene (scTRZ1) and humans, which contain one tRNase Z(L) encoded by the prostate-cancer susceptibility gene ELAC2 and one tRNase Z(S), Schizosaccharomyces pombe contains two tRNase Z(L) genes, designated sptrz1(+) and sptrz2(+). We report that both sptrz1(+) and sptrz2(+) are essential for growth. Moreover, sptrz1(+) is required for cell viability in the absence of Sla1p, which is thought to be required for endonuclease-mediated maturation of pre-tRNA 3' ends in yeast. Both scTRZ1 and ELAC2 can complement a temperature-sensitive allele of sptrz1(+), sptrz1-1, but not the sptrz1 null mutant, indicating that despite exhibiting species specificity, tRNase Z(L)s are functionally conserved among S. cerevisiae, S. pombe and humans. Overexpression of sptrz1(+), scTRZ1 and ELAC2 can increase suppression of the UGA nonsense mutation ade6-704 through facilitating 3' end processing of the defective suppressor tRNA that mediates suppression. Our findings reveal that 3' end processing is a limiting step for defective tRNA maturation and demonstrate that overexpression of sptrz1(+), scTRZ1 and ELAC2 can promote defective tRNA 3' processing in vivo. Our results also support the notion that yeast tRNase Z(L) is absolutely required for 3' end processing of at least a few pre-tRNAs even in the absence of Sla1p.
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30
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Dutta T, Deutscher MP. Catalytic properties of RNase BN/RNase Z from Escherichia coli: RNase BN is both an exo- and endoribonuclease. J Biol Chem 2009; 284:15425-31. [PMID: 19366704 PMCID: PMC2708839 DOI: 10.1074/jbc.m109.005462] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2009] [Revised: 04/07/2009] [Indexed: 11/06/2022] Open
Abstract
Processing of the 3' terminus of tRNA in many organisms is carried out by an endoribonuclease termed RNase Z or 3'-tRNase, which cleaves after the discriminator nucleotide to allow addition of the universal -CCA sequence. In some eubacteria, such as Escherichia coli, the -CCA sequence is encoded in all known tRNA genes. Nevertheless, an RNase Z homologue (RNase BN) is still present, even though its action is not needed for tRNA maturation. To help identify which RNA molecules might be potential substrates for RNase BN, we carried out a detailed examination of its specificity and catalytic potential using a variety of synthetic substrates. We show here that RNase BN is active on both double- and single-stranded RNA but that duplex RNA is preferred. The enzyme displays a profound base specificity, showing no activity on runs of C residues. RNase BN is strongly inhibited by the presence of a 3'-CCA sequence or a 3'-phosphoryl group. Digestion by RNase BN leads to 3-mers as the limit products, but the rate slows on molecules shorter than 10 nucleotides in length. Most interestingly, RNase BN acts as a distributive exoribonuclease on some substrates, releasing mononucleotides and a ladder of digestion products. However, RNase BN also cleaves endonucleolytically, releasing 3' fragments as short as 4 nucleotides. Although the presence of a 3'-phosphoryl group abolishes exoribonuclease action, it has no effect on the endoribonucleolytic cleavages. These data suggest that RNase BN may differ from other members of the RNase Z family, and they provide important information to be considered in identifying a physiological role for this enzyme.
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Affiliation(s)
- Tanmay Dutta
- From the Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, Miami, Florida 33101
| | - Murray P. Deutscher
- From the Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, Miami, Florida 33101
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Levinger L, Hopkinson A, Desetty R, Wilson C. Effect of changes in the flexible arm on tRNase Z processing kinetics. J Biol Chem 2009; 284:15685-91. [PMID: 19351879 DOI: 10.1074/jbc.m900745200] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
tRNAs are transcribed as precursors and processed in a series of reactions culminating in aminoacylation and translation. Central to tRNA maturation, the 3' end trailer can be endonucleolytically removed by tRNase Z. A flexible arm (FA) extruded from the body of tRNase Z consists of a structured alphaalphabetabeta hand that binds the elbow of pre-tRNA. Deleting the FA hand causes an almost 100-fold increase in Km with little change in kcat, establishing its contribution to substrate recognition/binding. Remarkably, a 40-residue Ala scan through the FA hand reveals a conserved leucine at the ascending stalk/hand boundary that causes practically the same increase in Km as the hand deletion, thus nearly eliminating its ability to bind substrate. Km also increases with substitutions in the GP (alpha4-alpha5) loop and at other conserved residues in the FA hand predicted to contact substrate based on the co-crystal structure. Substitutions that reduce kcat are clustered in the beta10-beta11 loop.
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Affiliation(s)
- Louis Levinger
- Department of Biology, York College of the City University of New York, Jamaica, New York 11451, USA.
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Takaku H, Nashimoto M. Escherichia coli tRNase Z can shut down growth probably by removing amino acids from aminoacyl-tRNAs. Genes Cells 2009; 13:1087-97. [PMID: 18823332 DOI: 10.1111/j.1365-2443.2008.01230.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In most organisms, tRNase Z is considered to be essential for 3' processing of tRNA molecules. The Escherichia coli tRNase Z gene, however, appears to be dispensable under normal growth conditions, and its existence remained an enigma. Here we intensively examined various (pre-)tRNAs for good substrates of E. coli tRNase Z in vitro, and found that the enzyme can remove the 3' terminal CCA residues from mature tRNAs regardless of their nucleotide modifications. Furthermore, we discovered that E. coli tRNase Z, when sufficiently expressed in the cell, can shut down growth probably by removing amino acids from aminoacyl-tRNAs. We confirmed in vitro that E. coli tRNase Z exceptionally possesses the activity that cleaves off the 3' terminal residues charging an amino acid from an aminoacyl-tRNA molecule. The current data suggest that tRNase Z might help modulate a cell growth rate by repressing translation under some stressful conditions.
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Affiliation(s)
- Hiroaki Takaku
- Department of Applied Life Sciences, Niigata University of Pharmacy and Applied Life Sciences, Niigata 956-8603, Japan
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Hartmann RK, Gössringer M, Späth B, Fischer S, Marchfelder A. The making of tRNAs and more - RNase P and tRNase Z. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2009; 85:319-68. [PMID: 19215776 DOI: 10.1016/s0079-6603(08)00808-8] [Citation(s) in RCA: 101] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Transfer-RNA (tRNA) molecules are essential players in protein biosynthesis. They are transcribed as precursors, which have to be extensively processed at both ends to become functional adaptors in protein synthesis. Two endonucleases that directly interact with the tRNA moiety, RNase P and tRNase Z, remove extraneous nucleotides on the molecule's 5'- and 3'-side, respectively. The ribonucleoprotein enzyme RNase P was identified almost 40 years ago and is considered a vestige from the "RNA world". Here, we present the state of affairs on prokaryotic RNase P, with a focus on recent findings on its role in RNA metabolism. tRNase Z was only identified 6 years ago, and we do not yet have a comprehensive understanding of its function. The current knowledge on prokaryotic tRNase Z in tRNA 3'-processing is reviewed here. A second, tRNase Z-independent pathway of tRNA 3'-end maturation involving 3'-exonucleases will also be discussed.
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Affiliation(s)
- Roland K Hartmann
- Philipps-Universität Marburg, Institut für Pharmazeutische Chemie, Marbacher Weg 6, D-35037 Marburg, Germany
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34
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Elbarbary RA, Takaku H, Nashimoto M. Functional analyses for tRNase Z variants: an aspartate and a histidine in the active site are essential for the catalytic activity. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2008; 1784:2079-85. [PMID: 18809514 DOI: 10.1016/j.bbapap.2008.08.019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2008] [Revised: 08/22/2008] [Accepted: 08/25/2008] [Indexed: 10/21/2022]
Abstract
We performed functional analyses for various single amino-acid substitution variants of Escherichia coli, Bacillus subtilis, and human tRNase Zs. The well-conserved six histidine, His(I)-His(VI), and two aspartate, Asp(I) and Asp(II), residues together with metal ions are thought to form the active site of tRNase Z. The Mn(2+)-rescue analysis for Thermotoga maritima tRNase Z(S) has suggested that Asp(I) and His(V) directly contribute the proton transfer for the catalysis, and a catalytic mechanism has been proposed. However, experimental evidence supporting the proposed mechanism was limited. Here we intensively examined E. coli and B. subtilis tRNase Z(S) variants and human tRNase Z(L) variants for cleavage activities on pre-tRNAs in the presence of Mg(2+) or Mn(2+) ions. We observed that the Mn(2+) ions cannot rescue the activities of Asp(I)Ala and His(V)Ala variants from each species, which are lost in the presence of Mg(2+). This observation may support the proposed catalytic mechanism.
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Affiliation(s)
- Reyad A Elbarbary
- Department of Applied Life Sciences, Niigata University of Pharmacy and Applied Life Sciences, Niigata, Niigata 956-8603, Japan
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Takahashi M, Takaku H, Nashimoto M. Regulation of the human tRNase ZSgene expression. FEBS Lett 2008; 582:2532-6. [DOI: 10.1016/j.febslet.2008.06.020] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2008] [Revised: 05/11/2008] [Accepted: 06/13/2008] [Indexed: 10/21/2022]
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Minagawa A, Ishii R, Takaku H, Yokoyama S, Nashimoto M. The flexible arm of tRNase Z is not essential for pre-tRNA binding but affects cleavage site selection. J Mol Biol 2008; 381:289-99. [PMID: 18602113 DOI: 10.1016/j.jmb.2008.05.016] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2007] [Revised: 05/02/2008] [Accepted: 05/08/2008] [Indexed: 10/22/2022]
Abstract
tRNase Z is an enzyme responsible for removing a 3' trailer from pre-tRNA. Although most tRNase Zs cleave pre-tRNAs immediately after the discriminator nucleotide with the exception of Thermotoga maritima tRNase Z, which cleaves after the (74)CCA(76) sequence, our knowledge was limited about how the cleavage site in pre-tRNA is selected. Bacterial tRNase Zs contain a unique domain termed flexible arm, which extends from the core domain. Using various tRNase Z variants, here we examined how the flexible arm affects the cleavage site selection. T. maritima tRNase Z variants with modified flexible arms shifted the cleavage site and a Bacillus subtilis tRNase Z variant with no flexible arm showed an anomalous cleavage activity. Some of the T. maritima/B. subtilis chimeric enzymes had both properties: they recognized (74)CCA(76)-containing pre-tRNA and cleaved it after the discriminator. Taken together, the present data indicate that the flexible arm is not essential for pre-tRNA binding but affects the cleavage site selection probably by pushing the distal region of the T arm in such a way that the discriminator nucleotide becomes closer to the catalytic site.
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Affiliation(s)
- Asako Minagawa
- Department of Applied Life Sciences, Niigata University of Pharmacy and Applied Life Sciences, Niigata 956-8603, Japan
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Lalonde MS, Zuo Y, Zhang J, Gong X, Wu S, Malhotra A, Li Z. Exoribonuclease R in Mycoplasma genitalium can carry out both RNA processing and degradative functions and is sensitive to RNA ribose methylation. RNA (NEW YORK, N.Y.) 2007; 13:1957-68. [PMID: 17872508 PMCID: PMC2040080 DOI: 10.1261/rna.706207] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Mycoplasma genitalium, a small bacterium having minimal genome size, has only one identified exoribonuclease, RNase R (MgR). We have purified MgR to homogeneity, and compared its RNA degradative properties to those of its Escherichia coli homologs RNase R (EcR) and RNase II (EcII). MgR is active on a number of substrates including oligoribonucleotides, poly(A), rRNA, and precursors to tRNA. Unlike EcR, which degrades rRNA and pre-tRNA without formation of intermediate products, MgR appears sensitive to certain RNA structural features and forms specific products from these stable RNA substrates. The 3'-ends of two MgR degradation products of 23S rRNA were mapped by RT-PCR to positions 2499 and 2553, each being 1 nucleotide downstream of a 2'-O-methylation site. The sensitivity of MgR to ribose methylation is further demonstrated by the degradation patterns of 16S rRNA and a synthetic methylated oligoribonucleotide. Remarkably, MgR removes the 3'-trailer sequence from a pre-tRNA, generating product with the mature 3'-end more efficiently than EcII does. In contrast, EcR degrades this pre-tRNA without the formation of specific products. Our results suggest that MgR shares some properties of both EcR and EcII and can carry out a broad range of RNA processing and degradative functions.
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Affiliation(s)
- Maureen S Lalonde
- Department of Biomedical Science, Florida Atlantic University, Boca Raton, FL 33431, USA
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Karkashon S, Hopkinson A, Levinger L. tRNase Z catalysis and conserved residues on the carboxy side of the His cluster. Biochemistry 2007; 46:9380-7. [PMID: 17655328 PMCID: PMC2526284 DOI: 10.1021/bi700578v] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
tRNAs are transcribed as precursors and processed in a series of required reactions leading to aminoacylation and translation. The 3'-end trailer can be removed by the pre-tRNA processing endonuclease tRNase Z, an ancient, conserved member of the beta-lactamase superfamily of metal-dependent hydrolases. The signature sequence of this family, the His domain (HxHxDH, Motif II), and histidines in Motifs III and V and aspartate in Motif IV contribute seven side chains for the coordination of two divalent metal ions. We previously investigated the effects on catalysis of substitutions in Motif II and in the PxKxRN loop and Motif I on the amino side of Motif II. Herein, we present the effects of substitutions on the carboxy side of Motif II within Motifs III, IV, the HEAT and HST loops, and Motif V. Substitution of the Motif IV aspartate reduces catalytic efficiency more than 10,000-fold. Histidines in Motif III, V, and the HST loop are also functionally important. Strikingly, replacement of Glu in the HEAT loop with Ala reduces efficiency by approximately 1000-fold. Proximity and orientation of this Glu side chain relative to His in the HST loop and the importance of both residues for catalysis suggest that they function as a duo in proton transfer at the final stage of reaction, characteristic of the tRNase Z class of RNA endonucleases.
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Affiliation(s)
| | | | - Louis Levinger
- *to whom correspondence should be addressed: Phone: 718-262-2704 FAX: 718-262-2652
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Ishii R, Minagawa A, Takaku H, Takagi M, Nashimoto M, Yokoyama S. The structure of the flexible arm of Thermotoga maritima tRNase Z differs from those of homologous enzymes. Acta Crystallogr Sect F Struct Biol Cryst Commun 2007; 63:637-41. [PMID: 17671357 PMCID: PMC2335171 DOI: 10.1107/s1744309107033623] [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: 04/23/2007] [Accepted: 07/10/2007] [Indexed: 11/11/2022]
Abstract
tRNA 3'-processing endoribonuclease (tRNase Z) is one of the enzymes involved in the 3'-end processing of precursor tRNAs and is a member of the metallo-beta-lactamase superfamily. tRNase Z crystal structures have revealed that the enzyme forms a dimer and has a characteristic domain, named a flexible arm or an exosite, which protrudes from the metallo-beta-lactamase core and is involved in tRNA binding. The refined structure of Thermotoga maritima tRNase Z has been determined at 1.97 A resolution, revealing the structure of the flexible arm and the zinc-bound active site. The structure of the flexible arm of T. maritima tRNase Z is distinct from those of the Bacillus subtilis and Escherichia coli tRNase Zs. A comparison of the three tRNase Z structures revealed differences in the dimer orientation, which may be related to the unique cleavage-site specificity of T. maritima tRNase Z.
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Affiliation(s)
- Ryohei Ishii
- RIKEN Genomic Sciences Center, Tsurumi, Yokohama 230-0045, Japan
| | - Asako Minagawa
- Department of Applied Life Sciences, Niigata University of Pharmacy and Applied Life Sciences, Niigata 956-8603, Japan
| | - Hiroaki Takaku
- Department of Applied Life Sciences, Niigata University of Pharmacy and Applied Life Sciences, Niigata 956-8603, Japan
| | - Masamichi Takagi
- Department of Applied Life Sciences, Niigata University of Pharmacy and Applied Life Sciences, Niigata 956-8603, Japan
| | - Masayuki Nashimoto
- Department of Applied Life Sciences, Niigata University of Pharmacy and Applied Life Sciences, Niigata 956-8603, Japan
| | - Shigeyuki Yokoyama
- RIKEN Genomic Sciences Center, Tsurumi, Yokohama 230-0045, Japan
- Department of Biophysics and Biochemistry, Graduate School of Science, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
- Correspondence e-mail:
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Britton RA, Wen T, Schaefer L, Pellegrini O, Uicker WC, Mathy N, Tobin C, Daou R, Szyk J, Condon C. Maturation of the 5' end of Bacillus subtilis 16S rRNA by the essential ribonuclease YkqC/RNase J1. Mol Microbiol 2007; 63:127-38. [PMID: 17229210 DOI: 10.1111/j.1365-2958.2006.05499.x] [Citation(s) in RCA: 120] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Functional ribosomal RNAs are generated from longer precursor species in every organism known. Maturation of the 5' side of 16S rRNA in Escherichia coli is catalysed in a two-step process by the cooperative action of RNase E and RNase G. However, many bacteria lack RNase E and RNase G orthologues, raising the question as to how 16S rRNA processing occurs in these organisms. Here we show that the maturation of Bacillus subtilis 16S rRNA is also a two-step process and that the enzyme responsible for the generation of the mature 5' end is the widely distributed essential ribonuclease YkqC/RNase J1. Depletion of B. subtilis of RNase J1 results in an accumulation of 16S rRNA precursors in vivo. The precursor species are found in polysomes suggesting that they can function in translation. Mutation of the predicted catalytic site of RNase J1 abolishes both 16S rRNA processing and cell viability. Finally, purified RNase J1 can correctly mature precursor 16S rRNA assembled in 70S ribosomes, showing that its role is direct.
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Affiliation(s)
- Robert A Britton
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI 48824, USA
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41
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Condon C. Maturation and degradation of RNA in bacteria. Curr Opin Microbiol 2007; 10:271-8. [PMID: 17560162 DOI: 10.1016/j.mib.2007.05.008] [Citation(s) in RCA: 126] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2007] [Accepted: 05/21/2007] [Indexed: 11/20/2022]
Abstract
RNA decay plays an important role, not only in recycling nucleotides but also in determining the rapidity with which cells can react to changing growth conditions. The degradation process can be regulated, thus providing an often-underestimated means of controlling gene expression. Recent developments in the field of RNA maturation and decay in two key model organisms, Escherichia coli and Bacillus subtilis, include the resolution of the structures of many of the participants in these processes in E. coli and the identification of an enzyme in B. subtilis that appears to fit the bill as a major player in RNA decay in this organism.
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Affiliation(s)
- Ciarán Condon
- CNRS UPR 9073 (affiliated with Université de Paris 7 - Denis Diderot), Institut de Biologie Physico-Chimique, 13 rue Pierre et Marie Curie, 75005 Paris, France.
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Dominski Z. Nucleases of the metallo-beta-lactamase family and their role in DNA and RNA metabolism. Crit Rev Biochem Mol Biol 2007; 42:67-93. [PMID: 17453916 DOI: 10.1080/10409230701279118] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Proteins of the metallo-beta-lactamase family with either demonstrated or predicted nuclease activity have been identified in a number of organisms ranging from bacteria to humans and has been shown to be important constituents of cellular metabolism. Nucleases of this family are believed to utilize a zinc-dependent mechanism in catalysis and function as 5' to 3' exonucleases and or endonucleases in such processes as 3' end processing of RNA precursors, DNA repair, V(D)J recombination, and telomere maintenance. Examples of metallo-beta-lactamase nucleases include CPSF-73, a known component of the cleavage/polyadenylation machinery, which functions as the endonuclease in 3' end formation of both polyadenylated and histone mRNAs, and Artemis that opens DNA hairpins during V(D)J recombination. Mutations in two metallo-beta-lactamase nucleases have been implicated in human diseases: tRNase Z required for 3' processing of tRNA precursors has been linked to the familial form of prostate cancer, whereas inactivation of Artemis causes severe combined immunodeficiency (SCID). There is also a group of as yet uncharacterized proteins of this family in bacteria and archaea that based on sequence similarity to CPSF-73 are predicted to function as nucleases in RNA metabolism. This article reviews the cellular roles of nucleases of the metallo-beta-lactamase family and the recent advances in studying these proteins.
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Affiliation(s)
- Zbigniew Dominski
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA.
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Redko Y, Li de la Sierra-Gallay I, Condon C. When all's zed and done: the structure and function of RNase Z in prokaryotes. Nat Rev Microbiol 2007; 5:278-86. [PMID: 17363966 DOI: 10.1038/nrmicro1622] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
RNase Z is a widely distributed and often essential endoribonuclease that is responsible for the maturation of the 3'-end of a large family of transfer RNAs (tRNAs). Although it has been the subject of study for more than 25 years, interest in this enzyme intensified dramatically with the identification of the encoding gene in 2002. This led to the discovery of RNase Z in bacteria, in which the final step in the generation of the mature 3'-end of tRNAs had previously been assumed to be catalysed by exoribonucleases. It also led inevitably to structural studies, and the recent resolution of the structure of RNase Z in complex with tRNA has provided a detailed understanding of the molecular mechanisms of RNase Z substrate recognition and cleavage. The identification of the RNase Z gene also allowed the search for alternative substrates for this enzyme to begin in earnest. In this Review, we outline the important recent developments that have contributed to our understanding of this enzyme, particularly in prokaryotes.
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Affiliation(s)
- Yulia Redko
- Centre National de Recherche Scientifique (CNRS) UPR9073 (affiliated with Université Paris VII-Denis Diderot), Institut de Biologie, Physico-Chimique, 13 rue Pierre et Marie Curie, 75005 Paris, France
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Abstract
This chapter discusses several topics relating to the mechanisms of mRNA decay. These topics include the following: important physical properties of mRNA molecules that can alter their stability; methods for determining mRNA half-lives; the genetics and biochemistry of proteins and enzymes involved in mRNA decay; posttranscriptional modification of mRNAs; the cellular location of the mRNA decay apparatus; regulation of mRNA decay; the relationships among mRNA decay, tRNA maturation, and ribosomal RNA processing; and biochemical models for mRNA decay. Escherichia coli has multiple pathways for ensuring the effective decay of mRNAs and mRNA decay is closely linked to the cell's overall RNA metabolism. Finally, the chapter highlights important unanswered questions regarding both the mechanism and importance of mRNA decay.
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45
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Nakashima A, Nashimoto M, Tamura M. TRUE Gene Silencing: Unique Gene Silencing by the tRNA Maturase tRNase ZL under the Direction of Small-guide RNA. J Oral Biosci 2007. [DOI: 10.2330/joralbiosci.49.54] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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46
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Nakashima A, Nashimoto M, Tamura M. TRUE Gene Silencing : Unique Gene Silencing by the tRNA Maturase tRNase ZL under the Direction of Small-guide RNA. J Oral Biosci 2007. [DOI: 10.1016/s1349-0079(07)80016-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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47
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Nakashima A, Takaku H, Shibata HS, Negishi Y, Takagi M, Tamura M, Nashimoto M. Gene silencing by the tRNA maturase tRNase ZL under the direction of small-guide RNA. Gene Ther 2007; 14:78-85. [PMID: 16885998 DOI: 10.1038/sj.gt.3302841] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2006] [Revised: 05/30/2006] [Accepted: 06/28/2006] [Indexed: 11/08/2022]
Abstract
We have been developing a unique system for the downregulation of a gene expression through cutting a specific mRNA by the long form of tRNA 3'-processing endoribonuclease (tRNase Z(L)) under the direction of small-guide RNA (sgRNA). However, the efficacy of this system and the involvement of tRNase Z(L) in the living cells were not clear. Here we show, by targeting the exogenous luciferase gene, that the efficacy of the sgRNA/tRNase Z(L) method can become comparable to that of the RNA interference technology and that the gene silencing is owing to tRNase Z(L) directed by sgRNA not owing to a simple antisense effect. We also show that tRNase Z(L) together with sgRNA can downregulate expression of the endogenous human genes Bcl-2 and glycogen synthase kinase-3beta by degrading their mRNAs in cell culture. Furthermore, we demonstrate that a gene expression in the livers of postnatal mice can be inhibited by an only seven-nucleotide sgRNA. These data suggest that sgRNA might be utilized as therapeutic agents to treat diseases such as cancers and AIDS.
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Affiliation(s)
- A Nakashima
- Department of Applied Life Sciences, Niigata University of Pharmacy and Applied Life Sciences, Niigata, Niigata, Japan
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48
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Minagawa A, Takaku H, Ishii R, Takagi M, Yokoyama S, Nashimoto M. Identification by Mn2+ rescue of two residues essential for the proton transfer of tRNase Z catalysis. Nucleic Acids Res 2006; 34:3811-8. [PMID: 16916792 PMCID: PMC1540738 DOI: 10.1093/nar/gkl517] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Thermotoga maritima tRNase Z cleaves pre-tRNAs containing the 74CCA76 sequence precisely after the A76 residue to create the mature 3' termini. Its crystal structure has revealed a four-layer alphabeta/betaalpha sandwich fold that is typically found in the metallo-beta-lactamase superfamily. The well-conserved six histidine and two aspartate residues together with metal ions are assumed to form the tRNase Z catalytic center. Here, we examined tRNase Z variants containing single amino acid substitutions in the catalytic center for pre-tRNA cleavage. Cleavage by each variant in the presence of Mg2+ was hardly detected, although it is bound to pre-tRNA. Surprisingly, however, Mn2+ ions restored the lost Mg2+-dependent activity with two exceptions of the Asp52Ala and His222Ala substitutions, which abolished the activity almost completely. These results provide a piece of evidence that Asp-52 and His-222 directly contribute the proton transfer for the catalysis.
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Affiliation(s)
| | | | - Ryohei Ishii
- RIKEN Genomic Sciences CenterTsurumi, Yokohama 230-0045, Japan
| | | | - Shigeyuki Yokoyama
- RIKEN Genomic Sciences CenterTsurumi, Yokohama 230-0045, Japan
- RIKEN Harima Institute at SPring-8Sayo-gun, Hyogo 679-5148, Japan
- Department of Biophysics and Biochemistry, Graduate School of Science, The University of TokyoBunkyo-ku, Tokyo 113-0033, Japan
| | - Masayuki Nashimoto
- To whom correspondence should be addressed. Tel: +81 250 25 5119; Fax: +81 250 25 5021;
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Vogel A, Schilling O, Späth B, Marchfelder A. The tRNase Z family of proteins: physiological functions, substrate specificity and structural properties. Biol Chem 2006; 386:1253-64. [PMID: 16336119 DOI: 10.1515/bc.2005.142] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
tRNase Z is the endoribonuclease that generates the mature 3'-end of tRNA molecules by removal of the 3'-trailer elements of precursor tRNAs. This enzyme has been characterized from representatives of all three domains of life (Bacteria, Archaea and Eukarya), as well as from mitochondria and chloroplasts. tRNase Z enzymes come in two forms: short versions (280-360 amino acids in length), present in all three kingdoms, and long versions (750-930 amino acids), present only in eukaryotes. The recently solved crystal structure of the bacterial tRNase Z provides the structural basis for the understanding of central functional elements. The substrate is recognized by an exosite that protrudes from the main protein body and consists of a metallo-beta-lactamase domain. Cleavage of the precursor tRNA occurs at the binuclear zinc site located in the other subunit of the functional homodimer. The first gene of the tRNase Z family was cloned in 2002. Since then a comprehensive set of data has been acquired concerning this new enzyme, including detailed functional studies on purified recombinant enzymes, mutagenesis studies and finally the determination of the crystal structure of three bacterial enzymes. This review summarizes the current knowledge about these exciting enzymes.
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Affiliation(s)
- Andreas Vogel
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, D-45470 Mülheim, Germany
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Shibata HS, Minagawa A, Takaku H, Takagi M, Nashimoto M. Unstructured RNA is a substrate for tRNase Z. Biochemistry 2006; 45:5486-92. [PMID: 16634630 DOI: 10.1021/bi051972s] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
tRNase Z, which exists in almost all cells, is believed to be working primarily for tRNA 3' maturation. In Escherichia coli, however, the tRNase Z gene appears to be dispensable under normal growth conditions, and its physiological role is not clear. Here, to investigate a possibility that E. coli tRNase Z cleaves RNAs other than pre-tRNAs, we tested several unstructured RNAs for cleavage. Surprisingly, all these substrates were cleaved very efficiently at multiple sites by a recombinant E. coli enzyme in vitro. tRNase Zs from Bacillus subtilis and Thermotoga maritima also cleaved various unstructured RNAs. The E. coli and B. subtilis enzymes seem to have a tendency to cleave after cytidine or before uridine, while cleavage by the T. maritima enzyme inevitably occurred after CCA in addition to the other cleavages. Assays to determine optimal conditions indicated that metal ion requirements differ between B. subtilis and T. maritima tRNase Zs. There was no significant difference in the observed rate constant between unstructured RNA and pre-tRNA substrates, while the K(d) value of a tRNase Z/unstructured RNA complex was much higher than that of an enzyme/pre-tRNA complex. Furthermore, eukaryotic tRNase Zs from yeast, pig, and human cleaved unstructured RNA at multiple sites, but an archaeal tRNase Z from Pyrobaculum aerophilum did not.
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Affiliation(s)
- Hirotaka S Shibata
- Department of Applied Life Sciences, Niigata University of Pharmacy and Applied Life Sciences, Niigata, Niigata 956-8603, Japan
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