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Kasho K, Sakai R, Ito K, Nakagaki W, Satomura R, Jinnouchi T, Ozaki S, Katayama T. Read-through transcription of tRNA underlies the cell cycle-dependent dissociation of IHF from the DnaA-inactivating sequence datA. Front Microbiol 2024; 15:1360108. [PMID: 38505555 PMCID: PMC10950094 DOI: 10.3389/fmicb.2024.1360108] [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: 12/22/2023] [Accepted: 02/05/2024] [Indexed: 03/21/2024] Open
Abstract
Timely initiation of chromosomal DNA replication in Escherichia coli is achieved by cell cycle-coordinated regulation of the replication origin, oriC, and the replication initiator, ATP-DnaA. Cellular levels of ATP-DnaA increase and peak at the time for initiation at oriC, after which hydrolysis of DnaA-bound ATP causes those to fall, yielding initiation-inactive ADP-DnaA. This hydrolysis is facilitated by the chromosomal locus datA located downstream of the tRNA-Gly (glyV-X-Y) operon, which possesses a cluster of DnaA-binding sequences and a single binding site (IBS) for the DNA bending protein IHF (integration host factor). While IHF binding activates the datA function and is regulated to occur specifically at post-initiation time, the underlying regulatory mechanisms remain obscure. Here, we demonstrate that datA-IHF binding at pre-initiation time is down-regulated depending on the read-through transcription of datA IBS initiated at the glyV-X-Y promoter. During the cell cycle, the level of read-through transcription, but not promoter activity, fluctuated in a manner inversely related to datA-IHF binding. Transcription from the glyV-X-Y promoter was predominantly interrupted at datA IBS by IHF binding. The terminator/attenuator sequence of the glyV-X-Y operon, as well as DnaA binding within datA overall, contributed to attenuation of transcription upstream of datA IBS, preserving the timely fluctuation of read-through transcription. These findings provide a mechanistic insight of tRNA transcription-dependent datA-IHF regulation, in which an unidentified factor is additionally required for the timely datA-IHF dissociation, and support the significance of datA for controlling the cell cycle progression as a connecting hub of tRNA production and replication initiation.
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2
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Xu X, Usher B, Gutierrez C, Barriot R, Arrowsmith TJ, Han X, Redder P, Neyrolles O, Blower TR, Genevaux P. MenT nucleotidyltransferase toxins extend tRNA acceptor stems and can be inhibited by asymmetrical antitoxin binding. Nat Commun 2023; 14:4644. [PMID: 37591829 PMCID: PMC10435456 DOI: 10.1038/s41467-023-40264-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Accepted: 07/20/2023] [Indexed: 08/19/2023] Open
Abstract
Mycobacterium tuberculosis, the bacterium responsible for human tuberculosis, has a genome encoding a remarkably high number of toxin-antitoxin systems of largely unknown function. We have recently shown that the M. tuberculosis genome encodes four of a widespread, MenAT family of nucleotidyltransferase toxin-antitoxin systems. In this study we characterize MenAT1, using tRNA sequencing to demonstrate MenT1 tRNA modification activity. MenT1 activity is blocked by MenA1, a short protein antitoxin unrelated to the MenA3 kinase. X-ray crystallographic analysis shows blockage of the conserved MenT fold by asymmetric binding of MenA1 across two MenT1 protomers, forming a heterotrimeric toxin-antitoxin complex. Finally, we also demonstrate tRNA modification by toxin MenT4, indicating conserved activity across the MenT family. Our study highlights variation in tRNA target preferences by MenT toxins, selective use of nucleotide substrates, and diverse modes of MenA antitoxin activity.
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Affiliation(s)
- Xibing Xu
- Laboratoire de Microbiologie et Génétique Moléculaires (LMGM), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, Université Toulouse III - Paul Sabatier (UT3), Toulouse, France
| | - Ben Usher
- Department of Biosciences, Durham University, South Road, Durham, DH1 3LE, UK
| | - Claude Gutierrez
- Institut de Pharmacologie et de Biologie Structurale (IPBS), Université de Toulouse, CNRS, Université Toulouse III - Paul Sabatier (UT3), Toulouse, France
| | - Roland Barriot
- Laboratoire de Microbiologie et Génétique Moléculaires (LMGM), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, Université Toulouse III - Paul Sabatier (UT3), Toulouse, France
| | - Tom J Arrowsmith
- Department of Biosciences, Durham University, South Road, Durham, DH1 3LE, UK
| | - Xue Han
- Laboratoire de Microbiologie et Génétique Moléculaires (LMGM), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, Université Toulouse III - Paul Sabatier (UT3), Toulouse, France
| | - Peter Redder
- Laboratoire de Microbiologie et Génétique Moléculaires (LMGM), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, Université Toulouse III - Paul Sabatier (UT3), Toulouse, France
| | - Olivier Neyrolles
- Institut de Pharmacologie et de Biologie Structurale (IPBS), Université de Toulouse, CNRS, Université Toulouse III - Paul Sabatier (UT3), Toulouse, France
| | - Tim R Blower
- Department of Biosciences, Durham University, South Road, Durham, DH1 3LE, UK.
| | - Pierre Genevaux
- Laboratoire de Microbiologie et Génétique Moléculaires (LMGM), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, Université Toulouse III - Paul Sabatier (UT3), Toulouse, France.
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3
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Abstract
The study of eukaryotic tRNA processing has given rise to an explosion of new information and insights in the last several years. We now have unprecedented knowledge of each step in the tRNA processing pathway, revealing unexpected twists in biochemical pathways, multiple new connections with regulatory pathways, and numerous biological effects of defects in processing steps that have profound consequences throughout eukaryotes, leading to growth phenotypes in the yeast Saccharomyces cerevisiae and to neurological and other disorders in humans. This review highlights seminal new results within the pathways that comprise the life of a tRNA, from its birth after transcription until its death by decay. We focus on new findings and revelations in each step of the pathway including the end-processing and splicing steps, many of the numerous modifications throughout the main body and anticodon loop of tRNA that are so crucial for tRNA function, the intricate tRNA trafficking pathways, and the quality control decay pathways, as well as the biogenesis and biology of tRNA-derived fragments. We also describe the many interactions of these pathways with signaling and other pathways in the cell.
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Affiliation(s)
- Eric M Phizicky
- Department of Biochemistry and Biophysics and Center for RNA Biology, University of Rochester School of Medicine, Rochester, New York 14642, USA
| | - Anita K Hopper
- Department of Molecular Genetics and Center for RNA Biology, Ohio State University, Columbus, Ohio 43235, USA
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4
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Abula A, Yang T, Zhang Y, Li T, Ji X. Enhancement of Escherichia coli Ribonuclease R Cytosine-Sensitive Activity by Single Amino Acid Substitution. Mol Biotechnol 2023; 65:108-115. [PMID: 35838865 DOI: 10.1007/s12033-022-00533-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Accepted: 06/30/2022] [Indexed: 02/07/2023]
Abstract
Exoribonucleases are frequently used as nuclei acids detection tools for their sequences, modifications, and structures. Escherichia coli ribonuclease R (EcR) is the prototypical exoribonuclease of the RNase II/RNB family degrading RNA in the 3'-5' direction. Different from RNase II, EcR is capable of degrading structured RNA efficiently, which makes it a potential analysis tool for various RNA species. In this work, we examined the nuclease activity of EcR degrading a series of RNA substrates with various sequences. Our biochemical work reveals that EcR is significantly sensitive to cytosine compared with other bases when catalyzing RNA degradation. EcR shows higher cytosine sensitivity compared to its homolog RNase II when degrading RNAs, and the hydrolysis process of EcR is transiently halted and produces apparent intermediate product when the 1-nt upstream of C is A or U, or G. Furthermore, the substitution of glycine with proline (G273P) in EcR enhances its cytosine sensitivity. These findings expand our understanding of EcR enzymatic activities. The EcR G273P mutant bearing higher cytosine sensitivity could help enrich cytosine trails in RNAs and will have potential implications in the detection and analysis of various RNA species especially small RNAs in biological and clinical samples.
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Affiliation(s)
- Abudureyimu Abula
- The State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, 210023, Jiangsu, People's Republic of China.,School of Basic Medical Sciences, Xinjiang Medical University, Urumqi, 830054, Xinjiang, China
| | - Tingting Yang
- The State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, 210023, Jiangsu, People's Republic of China
| | - Yingxin Zhang
- The State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, 210023, Jiangsu, People's Republic of China
| | - Tinghan Li
- The State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, 210023, Jiangsu, People's Republic of China
| | - Xiaoyun Ji
- The State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, 210023, Jiangsu, People's Republic of China. .,Institute of Artificial Intelligence Biomedicine, Nanjing University, Nanjing, China. .,Chemistry and Biomedicine Innovation Center (ChemBIC), Nanjing University, 163 Xianlin Avenue, Nanjing, 210023, China. .,Ministry of Education, Engineering Research Center of Protein and Peptide Medicine, Nanjing, China.
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5
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Hager M, Pöhler MT, Reinhardt F, Wellner K, Hübner J, Betat H, Prohaska S, Mörl M. Substrate Affinity Versus Catalytic Efficiency: Ancestral Sequence Reconstruction of tRNA Nucleotidyltransferases Solves an Enzyme Puzzle. Mol Biol Evol 2022; 39:6835633. [PMID: 36409584 PMCID: PMC9728577 DOI: 10.1093/molbev/msac250] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In tRNA maturation, CCA-addition by tRNA nucleotidyltransferase is a unique and highly accurate reaction. While the mechanism of nucleotide selection and polymerization is well understood, it remains a mystery why bacterial and eukaryotic enzymes exhibit an unexpected and surprisingly low tRNA substrate affinity while they efficiently catalyze the CCA-addition. To get insights into the evolution of this high-fidelity RNA synthesis, the reconstruction and characterization of ancestral enzymes is a versatile tool. Here, we investigate a reconstructed candidate of a 2 billion years old CCA-adding enzyme from Gammaproteobacteria and compare it to the corresponding modern enzyme of Escherichia coli. We show that the ancestral candidate catalyzes an error-free CCA-addition, but has a much higher tRNA affinity compared with the extant enzyme. The consequence of this increased substrate binding is an enhanced reverse reaction, where the enzyme removes the CCA end from the mature tRNA. As a result, the ancestral candidate exhibits a lower catalytic efficiency in vitro as well as in vivo. Furthermore, the efficient tRNA interaction leads to a processive polymerization, while the extant enzyme catalyzes nucleotide addition in a distributive way. Thus, the modern enzymes increased their polymerization efficiency by lowering the binding affinity to tRNA, so that CCA synthesis is efficiently promoted due to a reduced reverse reaction. Hence, the puzzling and at a first glance contradicting and detrimental weak substrate interaction represents a distinct activity enhancement in the evolution of CCA-adding enzymes.
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Affiliation(s)
| | | | - Franziska Reinhardt
- Computational EvoDevo Group, Institute for Computer Science, Leipzig University, Härtelstr. 16-18, 04109 Leipzig, Germany,Interdisciplinary Centre for Bioinformatics, Leipzig University, Härtelstr. 16-18, 04109 Leipzig, Germany
| | - Karolin Wellner
- Institute for Biochemistry, Leipzig University, Brüderstraße 34, D-04103 Leipzig, Germany
| | - Jessica Hübner
- Computational EvoDevo Group, Institute for Computer Science, Leipzig University, Härtelstr. 16-18, 04109 Leipzig, Germany
| | - Heike Betat
- Institute for Biochemistry, Leipzig University, Brüderstraße 34, D-04103 Leipzig, Germany
| | - Sonja Prohaska
- Computational EvoDevo Group, Institute for Computer Science, Leipzig University, Härtelstr. 16-18, 04109 Leipzig, Germany,Interdisciplinary Centre for Bioinformatics, Leipzig University, Härtelstr. 16-18, 04109 Leipzig, Germany,Santa Fe Institute, 1399 Hyde Park Road, Santa Fe, NM 87501, USA,Complexity Science Hub Vienna, Josefstädter Str. 39, 1080 Wien, Austria
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6
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Sekulovski S, Trowitzsch S. Transfer RNA processing - from a structural and disease perspective. Biol Chem 2022; 403:749-763. [PMID: 35728022 DOI: 10.1515/hsz-2021-0406] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 05/24/2022] [Indexed: 01/05/2023]
Abstract
Transfer RNAs (tRNAs) are highly structured non-coding RNAs which play key roles in translation and cellular homeostasis. tRNAs are initially transcribed as precursor molecules and mature by tightly controlled, multistep processes that involve the removal of flanking and intervening sequences, over 100 base modifications, addition of non-templated nucleotides and aminoacylation. These molecular events are intertwined with the nucleocytoplasmic shuttling of tRNAs to make them available at translating ribosomes. Defects in tRNA processing are linked to the development of neurodegenerative disorders. Here, we summarize structural aspects of tRNA processing steps with a special emphasis on intron-containing tRNA splicing involving tRNA splicing endonuclease and ligase. Their role in neurological pathologies will be discussed. Identification of novel RNA substrates of the tRNA splicing machinery has uncovered functions unrelated to tRNA processing. Future structural and biochemical studies will unravel their mechanistic underpinnings and deepen our understanding of neurological diseases.
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Affiliation(s)
- Samoil Sekulovski
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Max-von-Laue-Strasse 9, D-60438 Frankfurt/Main, Germany
| | - Simon Trowitzsch
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Max-von-Laue-Strasse 9, D-60438 Frankfurt/Main, Germany
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7
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Herzel L, Stanley JA, Yao CC, Li GW. Ubiquitous mRNA decay fragments in E. coli redefine the functional transcriptome. Nucleic Acids Res 2022; 50:5029-5046. [PMID: 35524564 PMCID: PMC9122600 DOI: 10.1093/nar/gkac295] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Revised: 04/11/2022] [Accepted: 04/13/2022] [Indexed: 01/01/2023] Open
Abstract
Bacterial mRNAs have short life cycles, in which transcription is rapidly followed by translation and degradation within seconds to minutes. The resulting diversity of mRNA molecules across different life-cycle stages impacts their functionality but has remained unresolved. Here we quantitatively map the 3’ status of cellular RNAs in Escherichia coli during steady-state growth and report a large fraction of molecules (median>60%) that are fragments of canonical full-length mRNAs. The majority of RNA fragments are decay intermediates, whereas nascent RNAs contribute to a smaller fraction. Despite the prevalence of decay intermediates in total cellular RNA, these intermediates are underrepresented in the pool of ribosome-associated transcripts and can thus distort quantifications and differential expression analyses for the abundance of full-length, functional mRNAs. The large heterogeneity within mRNA molecules in vivo highlights the importance in discerning functional transcripts and provides a lens for studying the dynamic life cycle of mRNAs.
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Affiliation(s)
- Lydia Herzel
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
| | - Julian A Stanley
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
| | - Chun-Chen Yao
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
| | - Gene-Wei Li
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
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8
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Erber L, Betat H, Mörl M. CCA-Addition Gone Wild: Unusual Occurrence and Phylogeny of Four Different tRNA Nucleotidyltransferases in Acanthamoeba castellanii. Mol Biol Evol 2021; 38:1006-1017. [PMID: 33095240 PMCID: PMC7947759 DOI: 10.1093/molbev/msaa270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
tRNAs are important players in the protein synthesis machinery, where they act as adapter molecules for translating the mRNA codons into the corresponding amino acid sequence. In a series of highly conserved maturation steps, the primary transcripts are converted into mature tRNAs. In the amoebozoan Acanthamoeba castellanii, a highly unusual evolution of some of these processing steps was identified that are based on unconventional RNA polymerase activities. In this context, we investigated the synthesis of the 3'-terminal CCA-end that is added posttranscriptionally by a specialized polymerase, the tRNA nucleotidyltransferase (CCA-adding enzyme). The majority of eukaryotic organisms carry only a single gene for a CCA-adding enzyme that acts on both the cytosolic and the mitochondrial tRNA pool. In a bioinformatic analysis of the genome of this organism, we identified a surprising multitude of genes for enzymes that contain the active site signature of eukaryotic/eubacterial tRNA nucleotidyltransferases. In vitro activity analyses of these enzymes revealed that two proteins represent bona fide CCA-adding enzymes, one of them carrying an N-terminal sequence corresponding to a putative mitochondrial target signal. The other enzymes have restricted activities and represent CC- and A-adding enzymes, respectively. The A-adding enzyme is of particular interest, as its sequence is closely related to corresponding enzymes from Proteobacteria, indicating a horizontal gene transfer. Interestingly, this unusual diversity of nucleotidyltransferase genes is not restricted to Acanthamoeba castellanii but is also present in other members of the Acanthamoeba genus, indicating an ancient evolutionary trait.
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Affiliation(s)
- Lieselotte Erber
- Institute for Biochemistry, Leipzig University, Leipzig, Germany
| | - Heike Betat
- Institute for Biochemistry, Leipzig University, Leipzig, Germany
| | - Mario Mörl
- Institute for Biochemistry, Leipzig University, Leipzig, Germany
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9
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Hennig O, Philipp S, Bonin S, Rollet K, Kolberg T, Jühling T, Betat H, Sauter C, Mörl M. Adaptation of the Romanomermis culicivorax CCA-Adding Enzyme to Miniaturized Armless tRNA Substrates. Int J Mol Sci 2020; 21:E9047. [PMID: 33260740 PMCID: PMC7730189 DOI: 10.3390/ijms21239047] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Accepted: 11/25/2020] [Indexed: 11/17/2022] Open
Abstract
The mitochondrial genome of the nematode Romanomermis culicivorax encodes for miniaturized hairpin-like tRNA molecules that lack D- as well as T-arms, strongly deviating from the consensus cloverleaf. The single tRNA nucleotidyltransferase of this organism is fully active on armless tRNAs, while the human counterpart is not able to add a complete CCA-end. Transplanting single regions of the Romanomermis enzyme into the human counterpart, we identified a beta-turn element of the catalytic core that-when inserted into the human enzyme-confers full CCA-adding activity on armless tRNAs. This region, originally identified to position the 3'-end of the tRNA primer in the catalytic core, dramatically increases the enzyme's substrate affinity. While conventional tRNA substrates bind to the enzyme by interactions with the T-arm, this is not possible in the case of armless tRNAs, and the strong contribution of the beta-turn compensates for an otherwise too weak interaction required for the addition of a complete CCA-terminus. This compensation demonstrates the remarkable evolutionary plasticity of the catalytic core elements of this enzyme to adapt to unconventional tRNA substrates.
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Affiliation(s)
- Oliver Hennig
- Institute for Biochemistry, Leipzig University, Brüderstraße 34, 04103 Leipzig, Germany; (O.H.); (S.P.); (S.B.); (K.R.); (T.K.); (T.J.); (H.B.)
| | - Susanne Philipp
- Institute for Biochemistry, Leipzig University, Brüderstraße 34, 04103 Leipzig, Germany; (O.H.); (S.P.); (S.B.); (K.R.); (T.K.); (T.J.); (H.B.)
| | - Sonja Bonin
- Institute for Biochemistry, Leipzig University, Brüderstraße 34, 04103 Leipzig, Germany; (O.H.); (S.P.); (S.B.); (K.R.); (T.K.); (T.J.); (H.B.)
| | - Kévin Rollet
- Institute for Biochemistry, Leipzig University, Brüderstraße 34, 04103 Leipzig, Germany; (O.H.); (S.P.); (S.B.); (K.R.); (T.K.); (T.J.); (H.B.)
- Architecture et Réactivité de l’ARN, Université de Strasbourg, CNRS, IBMC, 67084 Strasbourg, France;
| | - Tim Kolberg
- Institute for Biochemistry, Leipzig University, Brüderstraße 34, 04103 Leipzig, Germany; (O.H.); (S.P.); (S.B.); (K.R.); (T.K.); (T.J.); (H.B.)
| | - Tina Jühling
- Institute for Biochemistry, Leipzig University, Brüderstraße 34, 04103 Leipzig, Germany; (O.H.); (S.P.); (S.B.); (K.R.); (T.K.); (T.J.); (H.B.)
- Architecture et Réactivité de l’ARN, Université de Strasbourg, CNRS, IBMC, 67084 Strasbourg, France;
| | - Heike Betat
- Institute for Biochemistry, Leipzig University, Brüderstraße 34, 04103 Leipzig, Germany; (O.H.); (S.P.); (S.B.); (K.R.); (T.K.); (T.J.); (H.B.)
| | - Claude Sauter
- Architecture et Réactivité de l’ARN, Université de Strasbourg, CNRS, IBMC, 67084 Strasbourg, France;
| | - Mario Mörl
- Institute for Biochemistry, Leipzig University, Brüderstraße 34, 04103 Leipzig, Germany; (O.H.); (S.P.); (S.B.); (K.R.); (T.K.); (T.J.); (H.B.)
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10
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Wang J, Toffano-Nioche C, Lorieux F, Gautheret D, Lehmann J. Accurate characterization of Escherichia coli tRNA modifications with a simple method of deep-sequencing library preparation. RNA Biol 2020; 18:33-46. [PMID: 32618488 DOI: 10.1080/15476286.2020.1790871] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
In conventional RNA high-throughput sequencing, modified bases prevent a large fraction of tRNA transcripts to be converted into cDNA libraries. Recent proposals aiming at resolving this issue take advantage of the interference of base modifications with RT enzymes to detect and identify them by establishing signals from aborted cDNA transcripts. Because some modifications, such as methyl groups, do almost not allow RT bypassing, demethylation and highly processive RT enzymes have been used to overcome these obstacles. Working with Escherichia coli as a model system, we show that with a conventional (albeit still engineered) RT enzyme and key optimizations in library preparation, all RT-impairing modifications can be highlighted along the entire tRNA length without demethylation procedure. This is achieved by combining deep-sequencing samples, which allows to establish aborted transcription signal of higher accuracy and reproducibility, with the potential for differentiating tiny differences in the state of modification of all cellular tRNAs. In addition, our protocol provides estimates of the relative tRNA abundance.
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Affiliation(s)
- Ji Wang
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC) , Gif-sur-Yvette, France
| | - Claire Toffano-Nioche
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC) , Gif-sur-Yvette, France
| | - Florence Lorieux
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC) , Gif-sur-Yvette, France
| | - Daniel Gautheret
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC) , Gif-sur-Yvette, France
| | - Jean Lehmann
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC) , Gif-sur-Yvette, France
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11
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Erber L, Hoffmann A, Fallmann J, Hagedorn M, Hammann C, Stadler PF, Betat H, Prohaska S, Mörl M. Unusual Occurrence of Two Bona-Fide CCA-Adding Enzymes in Dictyostelium discoideum. Int J Mol Sci 2020; 21:ijms21155210. [PMID: 32717856 PMCID: PMC7432833 DOI: 10.3390/ijms21155210] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 07/20/2020] [Accepted: 07/22/2020] [Indexed: 01/12/2023] Open
Abstract
Dictyostelium discoideum, the model organism for the evolutionary supergroup of Amoebozoa, is a social amoeba that, upon starvation, undergoes transition from a unicellular to a multicellular organism. In its genome, we identified two genes encoding for tRNA nucleotidyltransferases. Such pairs of tRNA nucleotidyltransferases usually represent collaborating partial activities catalyzing CC- and A-addition to the tRNA 3'-end, respectively. In D. discoideum, however, both enzymes exhibit identical activities, representing bona-fide CCA-adding enzymes. Detailed characterization of the corresponding activities revealed that both enzymes seem to be essential and are regulated inversely during different developmental stages of D. discoideum. Intriguingly, this is the first description of two functionally equivalent CCA-adding enzymes using the same set of tRNAs and showing a similar distribution within the cell. This situation seems to be a common feature in Dictyostelia, as other members of this phylum carry similar pairs of tRNA nucleotidyltransferase genes in their genome.
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Affiliation(s)
- Lieselotte Erber
- Institute for Biochemistry, University of Leipzig, Brüderstraße 34, 04103 Leipzig, Germany; (L.E.); (H.B.)
| | - Anne Hoffmann
- Interdisciplinary Center for Bioinformatics, Leipzig University, Härtelstraße 16-18, 04107 Leipzig, Germany; (A.H.); (J.F.); (P.F.S.); (S.P.)
| | - Jörg Fallmann
- Interdisciplinary Center for Bioinformatics, Leipzig University, Härtelstraße 16-18, 04107 Leipzig, Germany; (A.H.); (J.F.); (P.F.S.); (S.P.)
| | - Monica Hagedorn
- Ribogenetics Biochemistry Lab, Department of Life Sciences and Chemistry, Jacobs University Bremen gGmbH, Campus Ring 1, 28759 Bremen, Germany; (M.H.); (C.H.)
| | - Christian Hammann
- Ribogenetics Biochemistry Lab, Department of Life Sciences and Chemistry, Jacobs University Bremen gGmbH, Campus Ring 1, 28759 Bremen, Germany; (M.H.); (C.H.)
| | - Peter F. Stadler
- Interdisciplinary Center for Bioinformatics, Leipzig University, Härtelstraße 16-18, 04107 Leipzig, Germany; (A.H.); (J.F.); (P.F.S.); (S.P.)
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Competence Center for Scalable Data Services and Solutions, and Leipzig Research Center for Civilization Diseases, Leipzig University, 04103 Leipzig, Germany
- Max Planck Institute for Mathematics in the Sciences, 04103 Leipzig, Germany
- Facultad de Ciencias, Universidad National de Colombia, Sede Bogotá, Carrera 45 No. 26-85, Colombia
- Santa Fe Institute for Complex Systems, 1399 Hyde Park Road, Santa Fe, NM 87501, USA
- Department of Theoretical Chemistry of the University of Vienna, A-1090 Vienna, Austria
| | - Heike Betat
- Institute for Biochemistry, University of Leipzig, Brüderstraße 34, 04103 Leipzig, Germany; (L.E.); (H.B.)
| | - Sonja Prohaska
- Interdisciplinary Center for Bioinformatics, Leipzig University, Härtelstraße 16-18, 04107 Leipzig, Germany; (A.H.); (J.F.); (P.F.S.); (S.P.)
- Computational EvoDevo Group, Department of Computer Science, Leipzig University, Härtelstraße 16-18, 04107 Leipzig, Germany
| | - Mario Mörl
- Institute for Biochemistry, University of Leipzig, Brüderstraße 34, 04103 Leipzig, Germany; (L.E.); (H.B.)
- Correspondence: ; Tel.: +49-341-9736-911; Fax: +49-341-9736-919
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Czech A. Deep sequencing of tRNA's 3'-termini sheds light on CCA-tail integrity and maturation. RNA (NEW YORK, N.Y.) 2020; 26:199-208. [PMID: 31719125 PMCID: PMC6961547 DOI: 10.1261/rna.072330.119] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Accepted: 11/07/2019] [Indexed: 06/10/2023]
Abstract
The 3'-termini of tRNA are the point of amino acid linkage and thus crucial for their function in delivering amino acids to the ribosome and other enzymes. Therefore, to provide tRNA functionality, cells have to ensure the integrity of the 3'-terminal CCA-tail, which is generated during maturation by the 3'-trailer processing machinery and maintained by the CCA-adding enzyme. We developed a new tRNA sequencing method that is specifically tailored to assess the 3'-termini of E. coli tRNA. Intriguingly, we found a significant fraction of tRNAs with damaged CCA-tails under exponential growth conditions and, surprisingly, this fraction decreased upon transition into stationary phase. Interestingly, tRNAs bearing guanine as a discriminator base are generally unaffected by CCA-tail damage. In addition, we showed tRNA species-specific 3'-trailer processing patterns and reproduced in vitro findings on preferences of the maturation enzyme RNase T in vivo.
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Affiliation(s)
- Andreas Czech
- Institute of Biochemistry and Molecular Biology, Chemistry Department, University of Hamburg, 20146 Hamburg, Germany
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Erber L, Franz P, Betat H, Prohaska S, Mörl M. Divergent Evolution of Eukaryotic CC- and A-Adding Enzymes. Int J Mol Sci 2020; 21:ijms21020462. [PMID: 31936900 PMCID: PMC7014341 DOI: 10.3390/ijms21020462] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 01/06/2020] [Accepted: 01/09/2020] [Indexed: 12/04/2022] Open
Abstract
Synthesis of the CCA end of essential tRNAs is performed either by CCA-adding enzymes or as a collaboration between enzymes restricted to CC- and A-incorporation. While the occurrence of such tRNA nucleotidyltransferases with partial activities seemed to be restricted to Bacteria, the first example of such split CCA-adding activities was reported in Schizosaccharomyces pombe. Here, we demonstrate that the choanoflagellate Salpingoeca rosetta also carries CC- and A-adding enzymes. However, these enzymes have distinct evolutionary origins. Furthermore, the restricted activity of the eukaryotic CC-adding enzymes has evolved in a different way compared to their bacterial counterparts. Yet, the molecular basis is very similar, as highly conserved positions within a catalytically important flexible loop region are missing in the CC-adding enzymes. For both the CC-adding enzymes from S. rosetta as well as S. pombe, introduction of the loop elements from closely related enzymes with full activity was able to restore CCA-addition, corroborating the significance of this loop in the evolution of bacterial as well as eukaryotic tRNA nucleotidyltransferases. Our data demonstrate that partial CC- and A-adding activities in Bacteria and Eukaryotes are based on the same mechanistic principles but, surprisingly, originate from different evolutionary events.
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Affiliation(s)
- Lieselotte Erber
- Institute for Biochemistry, Leipzig University, Brüderstraße 34, 04103 Leipzig, Germany; (L.E.); (P.F.); (H.B.)
| | - Paul Franz
- Institute for Biochemistry, Leipzig University, Brüderstraße 34, 04103 Leipzig, Germany; (L.E.); (P.F.); (H.B.)
| | - Heike Betat
- Institute for Biochemistry, Leipzig University, Brüderstraße 34, 04103 Leipzig, Germany; (L.E.); (P.F.); (H.B.)
| | - Sonja Prohaska
- Computational EvoDevo Group, Department of Computer Science, Leipzig University, Härtelstraße 16-18, 04107 Leipzig, Germany;
- Interdisciplinary Center for Bioinformatics, Leipzig University, Härtelstraße 16-18, 04107 Leipzig, Germany
- Santa Fe Institute for Complex Systems, 1399 Hyde Park Road, Santa Fe, NM 87501, USA
| | - Mario Mörl
- Institute for Biochemistry, Leipzig University, Brüderstraße 34, 04103 Leipzig, Germany; (L.E.); (P.F.); (H.B.)
- Correspondence: ; Tel.: +49-341-9736-911; Fax: +49-341-9736-919
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14
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Wellner K, Pöhler MT, Betat H, Mörl M. Dual expression of CCA-adding enzyme and RNase T in Escherichia coli generates a distinct cca growth phenotype with diverse applications. Nucleic Acids Res 2019; 47:3631-3639. [PMID: 30828718 PMCID: PMC6468291 DOI: 10.1093/nar/gkz133] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Revised: 02/14/2019] [Accepted: 02/18/2019] [Indexed: 11/22/2022] Open
Abstract
Correct synthesis and maintenance of functional tRNA 3′-CCA-ends is a crucial prerequisite for aminoacylation and must be achieved by the phylogenetically diverse group of tRNA nucleotidyltransferases. While numerous reports on the in vitro characterization exist, robust analysis under in vivo conditions is lacking. Here, we utilize Escherichia coli RNase T, a tRNA-processing enzyme responsible for the tRNA-CCA-end turnover, to generate an in vivo system for the evaluation of A-adding activity. Expression of RNase T results in a prominent growth phenotype that renders the presence of a CCA- or A-adding enzyme essential for cell survival in an E. coli Δcca background. The distinct growth fitness allows for both complementation and selection of enzyme variants in a natural environment. We demonstrate the potential of our system via detection of altered catalytic efficiency and temperature sensitivity. Furthermore, we select functional enzyme variants out of a sequence pool carrying a randomized codon for a highly conserved position essential for catalysis. The presented E. coli-based approach opens up a wide field of future studies including the investigation of tRNA nucleotidyltransferases from all domains of life and the biological relevance of in vitro data concerning their functionality and mode of operation.
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Affiliation(s)
- Karolin Wellner
- Institute for Biochemistry, Leipzig University, Brüderstr. 34, 04103 Leipzig, Germany
| | - Marie-Theres Pöhler
- Institute for Biochemistry, Leipzig University, Brüderstr. 34, 04103 Leipzig, Germany
| | - Heike Betat
- Institute for Biochemistry, Leipzig University, Brüderstr. 34, 04103 Leipzig, Germany
| | - Mario Mörl
- Institute for Biochemistry, Leipzig University, Brüderstr. 34, 04103 Leipzig, Germany
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15
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Wellner K, Mörl M. Post-Transcriptional Regulation of tRNA Pools To Govern the Central Dogma: A Perspective. Biochemistry 2019; 58:299-304. [PMID: 30192518 DOI: 10.1021/acs.biochem.8b00862] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Since their initial discovery, tRNAs have risen from sole adapter molecules during protein synthesis to pivotal modulators of gene expression. Through their many interactions with tRNA-associated protein factors, they play a central role in maintaining cell homeostasis, especially regarding the fine-tuning in response to a rapidly changing cellular environment. Here, we provide a perspective on current tRNA topics with a spotlight on the regulation of post-transcriptional shaping of tRNA molecules. First, we give an update on aberrant structural features that a yet functional fraction of mitochondrial tRNAs can exhibit. Then, we outline several aspects of the regulatory contribution of ribonucleases with a focus on tRNA processing versus tRNA elimination. We close with a comment on the possible consequences for the intracellular examination of nascent tRNA precursors regarding respective processing factors that have been shown to associate with the tRNA transcription machinery in alternative moonlighting functions.
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Affiliation(s)
- Karolin Wellner
- Institute for Biochemistry , Leipzig University , Brüderstrasse 34 , 04103 Leipzig , Germany
| | - Mario Mörl
- Institute for Biochemistry , Leipzig University , Brüderstrasse 34 , 04103 Leipzig , Germany
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Mohanty BK, Kushner SR. Enzymes Involved in Posttranscriptional RNA Metabolism in Gram-Negative Bacteria. Microbiol Spectr 2018; 6:10.1128/microbiolspec.RWR-0011-2017. [PMID: 29676246 PMCID: PMC5912700 DOI: 10.1128/microbiolspec.rwr-0011-2017] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Indexed: 02/08/2023] Open
Abstract
Gene expression in Gram-negative bacteria is regulated at many levels, including transcription initiation, RNA processing, RNA/RNA interactions, mRNA decay, and translational controls involving enzymes that alter translational efficiency. In this review, we discuss the various enzymes that control transcription, translation, and RNA stability through RNA processing and degradation. RNA processing is essential to generate functional RNAs, while degradation helps control the steady-state level of each individual transcript. For example, all the pre-tRNAs are transcribed with extra nucleotides at both their 5' and 3' termini, which are subsequently processed to produce mature tRNAs that can be aminoacylated. Similarly, rRNAs that are transcribed as part of a 30S polycistronic transcript are matured to individual 16S, 23S, and 5S rRNAs. Decay of mRNAs plays a key role in gene regulation through controlling the steady-state level of each transcript, which is essential for maintaining appropriate protein levels. In addition, degradation of both translated and nontranslated RNAs recycles nucleotides to facilitate new RNA synthesis. To carry out all these reactions, Gram-negative bacteria employ a large number of endonucleases, exonucleases, RNA helicases, and poly(A) polymerase, as well as proteins that regulate the catalytic activity of particular RNases. Under certain stress conditions, an additional group of specialized endonucleases facilitate the cell's ability to adapt and survive. Many of the enzymes, such as RNase E, RNase III, polynucleotide phosphorylase, RNase R, and poly(A) polymerase I, participate in multiple RNA processing and decay pathways.
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Affiliation(s)
| | - Sidney R Kushner
- Department of Genetics
- Department of Microbiology, University of Georgia, Athens, GA 30602
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