1
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Wellner K, Gnauck J, Bernier D, Bernhart SH, Betat H, Mörl M. Two complementing in vivo selection systems based on CCA-trimming exonucleases as a tool to monitor, select and evaluate enzymatic features of tRNA nucleotidyltransferases. RNA Biol 2025; 22:1-14. [PMID: 39831457 PMCID: PMC11784652 DOI: 10.1080/15476286.2025.2453963] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2024] [Revised: 10/07/2024] [Accepted: 01/07/2025] [Indexed: 01/22/2025] Open
Abstract
tRNA nucleotidyltransferase represents a ubiquitous and essential activity that adds the indispensable CCA triplet to the 3'-end of tRNAs. To fulfill this function, the enzyme contains a set of highly conserved motifs whose coordinated interplay is crucial for the sequence-specific CCA polymerization. In the human enzyme, alterations within these regions have been shown to lead to the manifestation of disease. Recently, we developed an in vivo screening system that allows for the selection and analysis of tRNA nucleotidyltransferase variants by challenging terminal AMP incorporation into tRNA during induced RNase T-catalyzed CCA-decay. Here, we extend this method for screening of full CCA-end repair by utilizing the CCA-trimming activity of exonuclease LCCR4. To demonstrate the combined potential of these two in vivo selection systems, we applied a semi-rational library design to investigate the mode of operation of catalytically important motifs in the human CCA-adding enzyme. This approach revealed unexpected requirements for amino acid composition in two motifs and gives new insights into the mechanism of CCA addition. The data show the potential of these RNase-based screening systems, as they allow the detection of enzyme variations that would not have been identified by a conventional rational approach. Furthermore, the combination of both RNase T and LCCR4 systems can be used to investigate and dissect the effects of pathogenic mutations on C- and A-addition.
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Affiliation(s)
- Karolin Wellner
- Institute for Biochemistry, Leipzig University, Leipzig, Germany
| | - Josefine Gnauck
- Institute for Biochemistry, Leipzig University, Leipzig, Germany
| | - Dorian Bernier
- Institute for Biochemistry, Leipzig University, Leipzig, Germany
| | - Stephan H. Bernhart
- Bioinformatics Group, Department of Computer Science and Interdisciplinary Center for Bioinformatics, 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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2
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Abstract
Ribonucleases (RNases) are essential for almost every aspect of RNA metabolism. However, despite their important metabolic roles, RNases can also be destructive enzymes. As a consequence, cells must carefully regulate the amount, the activity, and the localization of RNases to avoid the inappropriate degradation of essential RNA molecules. In addition, bacterial cells often must adjust RNase levels as environmental situations demand, also requiring careful regulation of these critical enzymes. As the need for strict control of RNases has become more evident, multiple mechanisms for this regulation have been identified and studied, and these are described in this review. The major conclusion that emerges is that no common regulatory mechanism applies to all RNases, or even to a family of RNases; rather, a wide variety of processes have evolved that act on these enzymes, and in some cases, multiple regulatory mechanisms can even act on a single RNase. Expected final online publication date for the Annual Review of Microbiology, Volume 75 is October 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Murray P Deutscher
- Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, Florida 33101, USA;
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3
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Li ZW, Liang S, Ke Y, Deng JJ, Zhang MS, Lu DL, Li JZ, Luo XC. The feather degradation mechanisms of a new Streptomyces sp. isolate SCUT-3. Commun Biol 2020; 3:191. [PMID: 32332852 PMCID: PMC7181669 DOI: 10.1038/s42003-020-0918-0] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Accepted: 03/30/2020] [Indexed: 01/08/2023] Open
Abstract
Feather waste is the highest protein-containing resource in nature and is poorly reused. Bioconversion is widely accepted as a low-cost and environmentally benign process, but limited by the availability of safe and highly efficient feather degrading bacteria (FDB) for its industrial-scale fermentation. Excessive focuses on keratinase and limited knowledge of other factors have hindered complete understanding of the mechanisms employed by FDB to utilize feathers and feather cycling in the biosphere. Streptomyces sp. SCUT-3 can efficiently degrade feather to products with high amino acid content, useful as a nutrition source for animals, plants and microorganisms. Using multiple omics and other techniques, we reveal how SCUT-3 turns on its feather utilization machinery, including its colonization, reducing agent and protease secretion, peptide/amino acid importation and metabolism, oxygen consumption and iron uptake, spore formation and resuscitation, and so on. This study would shed light on the feather utilization mechanisms of FDBs. Li et a. report a new Streptromyces isolate, SCUT-3 which can efficiently degrade feather into products with high amino acid content, useful as feed for plants, animals and microbes. Using multiple omics and other techniques, they report how SCUT-3 turns on its feather utilization machinery and suggest a number of expressed genes most likely implicated in feather degradation.
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Affiliation(s)
- Zhi-Wei Li
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, Guangdong, P. R. China
| | - Shuang Liang
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, Guangdong, P. R. China
| | - Ye Ke
- Yingdong College of Life Sciences, Shaoguan University, Shaoguan, Guangdong, P. R. China
| | - Jun-Jin Deng
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, Guangdong, P. R. China
| | - Ming-Shu Zhang
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, Guangdong, P. R. China
| | - De-Lin Lu
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, Guangdong, P. R. China
| | - Jia-Zhou Li
- Zhanjiang Ocean Sciences and Technologies Research Co. LTD, Zhanjiang, Guangdong, P. R. China
| | - Xiao-Chun Luo
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, Guangdong, P. R. China.
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4
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Mohanty BK, Kushner SR. New Insights into the Relationship between tRNA Processing and Polyadenylation in Escherichia coli. Trends Genet 2019; 35:434-445. [PMID: 31036345 PMCID: PMC7368558 DOI: 10.1016/j.tig.2019.03.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Revised: 02/28/2019] [Accepted: 03/12/2019] [Indexed: 11/30/2022]
Abstract
Recent studies suggest that poly(A) polymerase I (PAP I)-mediated polyadenylation in Escherichia coli is highly prevalent among mRNAs as well as tRNA precursors. Primary tRNA transcripts are initially processed endonucleolytically to generate pre-tRNA species, which undergo 5'-end maturation by the ribozyme RNase P. Subsequently, a group of 3' → 5' exonucleases mature the 3' ends of the majority of tRNAs with few exceptions. PAP I competes with the 3' → 5' exonucleases for pre-tRNA substrates adding short poly(A) tails, which not only modulate the stability of the pre-tRNAs, but also regulate the availability of functional tRNAs. In this review, we discuss the recent discoveries of new tRNA processing pathways and the implications of polyadenylation in tRNA metabolism in E. coli.
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Affiliation(s)
- Bijoy K Mohanty
- Department of Genetics, University of Georgia, Athens, GA 30605, USA
| | - Sidney R Kushner
- Department of Genetics, University of Georgia, Athens, GA 30605, USA; Department of Microbiology, University of Georgia, Athens, GA 30605, USA.
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5
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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: 129] [Impact Index Per Article: 21.5] [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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6
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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: 41] [Impact Index Per Article: 5.9] [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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7
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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: 4.4] [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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8
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Chen H, Dutta T, Deutscher MP. Growth Phase-dependent Variation of RNase BN/Z Affects Small RNAs: REGULATION OF 6S RNA. J Biol Chem 2016; 291:26435-26442. [PMID: 27875308 DOI: 10.1074/jbc.m116.757450] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Revised: 11/07/2016] [Indexed: 01/01/2023] Open
Abstract
RNase BN, the RNase Z family member in E. coli, can participate in the processing of tRNA precursors. However, this function only becomes apparent when other processing enzymes are absent, raising the question of its primary physiological role. Here, we show that RNase BN itself is subject to growth phase-dependent regulation, because both rbn mRNA and RNase BN protein are at their highest levels in early exponential phase, but then decrease dramatically and are essentially absent in stationary phase. As a consequence of this variation, certain small RNAs, such as 6S RNA, remain low in exponential phase cells, and increase greatly in stationary phase. RNase BN affects 6S RNA abundance by decreasing its stability in exponential phase. RNase BN levels increase rapidly as cells exit stationary phase and are primarily responsible for the decrease in 6S RNA that accompanies this process. Purified RNase BN directly cleaves 6S RNA as shown by in vitro assays, and the 6S RNA:pRNA duplex is an even more favorable substrate of RNase BN. The exoribonuclease activity of RNase BN is unnecessary because all its action on 6S RNA is due to endonucleolytic cleavages. These data indicate that RNase BN plays an important role in determining levels of the global transcription regulator, 6S RNA, throughout the growth cycle.
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Affiliation(s)
- Hua Chen
- From the Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, Miami, Florida 33101
| | - 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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9
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Deutscher MP. How bacterial cells keep ribonucleases under control. FEMS Microbiol Rev 2015; 39:350-61. [PMID: 25878039 DOI: 10.1093/femsre/fuv012] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/02/2015] [Indexed: 11/13/2022] Open
Abstract
Ribonucleases (RNases) play an essential role in essentially every aspect of RNA metabolism, but they also can be destructive enzymes that need to be regulated to avoid unwanted degradation of RNA molecules. As a consequence, cells have evolved multiple strategies to protect RNAs against RNase action. They also utilize a variety of mechanisms to regulate the RNases themselves. These include post-transcriptional regulation, post-translational modification, trans-acting inhibitors, cellular localization, as well as others that are less well studied. In this review, I will briefly discuss how RNA molecules are protected and then examine in detail our current understanding of the mechanisms known to regulate individual RNases.
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Affiliation(s)
- Murray P Deutscher
- Biochemistry & Molecular Biology, University of Miami, Miami, FL 33136-6129, USA
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10
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Romero DA, Hasan AH, Lin YF, Kime L, Ruiz-Larrabeiti O, Urem M, Bucca G, Mamanova L, Laing EE, van Wezel GP, Smith CP, Kaberdin VR, McDowall KJ. A comparison of key aspects of gene regulation in Streptomyces coelicolor and Escherichia coli using nucleotide-resolution transcription maps produced in parallel by global and differential RNA sequencing. Mol Microbiol 2014; 94:963-987. [PMID: 25266672 PMCID: PMC4681348 DOI: 10.1111/mmi.12810] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/27/2014] [Indexed: 12/12/2022]
Abstract
Streptomyces coelicolor is a model for studying bacteria renowned as the foremost source of natural products used clinically. Post-genomic studies have revealed complex patterns of gene expression and links to growth, morphological development and individual genes. However, the underlying regulation remains largely obscure, but undoubtedly involves steps after transcription initiation. Here we identify sites involved in RNA processing and degradation as well as transcription within a nucleotide-resolution map of the transcriptional landscape. This was achieved by combining RNA-sequencing approaches suited to the analysis of GC-rich organisms. Escherichia coli was analysed in parallel to validate the methodology and allow comparison. Previously, sites of RNA processing and degradation had not been mapped on a transcriptome-wide scale for E. coli. Through examples, we show the value of our approach and data sets. This includes the identification of new layers of transcriptional complexity associated with several key regulators of secondary metabolism and morphological development in S. coelicolor and the identification of host-encoded leaderless mRNA and rRNA processing associated with the generation of specialized ribosomes in E. coli. New regulatory small RNAs were identified for both organisms. Overall the results illustrate the diversity in mechanisms used by different bacterial groups to facilitate and regulate gene expression.
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Affiliation(s)
- David A Romero
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of LeedsLeeds, LS2 9JT, UK
| | - Ayad H Hasan
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of LeedsLeeds, LS2 9JT, UK
| | - Yu-fei Lin
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of LeedsLeeds, LS2 9JT, UK
| | - Louise Kime
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of LeedsLeeds, LS2 9JT, UK
| | - Olatz Ruiz-Larrabeiti
- Department of Immunology, Microbiology and Parasitology, University of the Basque Country UPV/EHULeioa, Spain
| | - Mia Urem
- Institute of Biology, Sylvius Laboratories, Leiden UniversityLeiden, NL-2300 RA, The Netherlands
| | - Giselda Bucca
- Department of Microbial & Cellular Sciences, Faculty of Health & Medical Sciences, University of SurreyGuildford, GU2 7XH, UK
| | - Lira Mamanova
- The Wellcome Trust Sanger Institute, Wellcome Trust Genome CampusHinxton, Cambridge, CB10 1SA, UK
| | - Emma E Laing
- Department of Microbial & Cellular Sciences, Faculty of Health & Medical Sciences, University of SurreyGuildford, GU2 7XH, UK
| | - Gilles P van Wezel
- Institute of Biology, Sylvius Laboratories, Leiden UniversityLeiden, NL-2300 RA, The Netherlands
| | - Colin P Smith
- Department of Microbial & Cellular Sciences, Faculty of Health & Medical Sciences, University of SurreyGuildford, GU2 7XH, UK
| | - Vladimir R Kaberdin
- Department of Immunology, Microbiology and Parasitology, University of the Basque Country UPV/EHULeioa, Spain
- IKERBASQUE, Basque Foundation for Science48011, Bilbao, Spain
| | - Kenneth J McDowall
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of LeedsLeeds, LS2 9JT, UK
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11
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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: 1.2] [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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12
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Zhou L, Zhang AB, Wang R, Marcotte EM, Vogel C. The proteomic response to mutants of the Escherichia coli RNA degradosome. MOLECULAR BIOSYSTEMS 2013; 9:750-7. [PMID: 23403814 PMCID: PMC3709862 DOI: 10.1039/c3mb25513a] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The Escherichia coli RNA degradosome recognizes and degrades RNA through the coordination of four main protein components, the endonuclease RNase E, the exonuclease PNPase, the RhlB helicase and the metabolic enzyme enolase. To help our understanding of the functions of the RNA degradosome, we quantified expression changes of >2300 proteins using mass spectrometry based shotgun proteomics in E. coli strains deficient in rhlB, eno, pnp (which displays temperature sensitive growth), or rne(1-602) which encodes a C-terminal truncation mutant of RNase E and is deficient in degradosome assembly. Global protein expression changes are most similar between the pnp and rhlB mutants, confirming the functional relationship between the genes. We observe down-regulation of protein chaperones including GroEL and DnaK (which associate with the degradosome), a decrease in translation related proteins in Δpnp, ΔrhlB and rne(1-602) cells, and a significant increase in the abundance of aminoacyl-tRNA synthetases. Analysis of the observed proteomic changes points to a shared motif, CGCTGG, that may be associated with RNA degradosome targets. Further, our data provide information on the expression modulation of known degradosome-associated proteins, such as DeaD and RNase G, as well as other RNA helicases and RNases - suggesting or confirming functional complementarity in some cases. Taken together, our results emphasize the role of the RNA degradosome in the modulation of the bacterial proteome and provide the first large-scale proteomic description of the response to perturbation of this major pathway of RNA degradation.
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Affiliation(s)
- Li Zhou
- University of Texas at Austin, Center for Systems and Synthetic Biology, Institute for Cellular and Molecular Biology, Austin, TX
- Department of Molecular Biology, Department of Chemistry and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Ang B Zhang
- New York University, Department of Biology, Center for Genomics and Systems Biology, New York, NY
| | - Rong Wang
- University of Texas at Austin, Center for Systems and Synthetic Biology, Institute for Cellular and Molecular Biology, Austin, TX
- National Heart Lung and Blood Institute, NIH, NIH, Bethesda, Maryland, USA
| | - Edward M Marcotte
- University of Texas at Austin, Center for Systems and Synthetic Biology, Institute for Cellular and Molecular Biology, Austin, TX
| | - Christine Vogel
- University of Texas at Austin, Center for Systems and Synthetic Biology, Institute for Cellular and Molecular Biology, Austin, TX
- New York University, Department of Biology, Center for Genomics and Systems Biology, New York, NY
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13
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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: 1.3] [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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14
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Mohanty BK, Maples VF, Kushner SR. Polyadenylation helps regulate functional tRNA levels in Escherichia coli. Nucleic Acids Res 2012; 40:4589-603. [PMID: 22287637 PMCID: PMC3378859 DOI: 10.1093/nar/gks006] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2011] [Revised: 12/19/2011] [Accepted: 12/23/2011] [Indexed: 12/24/2022] Open
Abstract
Here we demonstrate a new regulatory mechanism for tRNA processing in Escherichia coli whereby RNase T and RNase PH, the two primary 3' → 5' exonucleases involved in the final step of 3'-end maturation, compete with poly(A) polymerase I (PAP I) for tRNA precursors in wild-type cells. In the absence of both RNase T and RNase PH, there is a >30-fold increase of PAP I-dependent poly(A) tails that are ≤10 nt in length coupled with a 2.3- to 4.2-fold decrease in the level of aminoacylated tRNAs and a >2-fold decrease in growth rate. Only 7 out of 86 tRNAs are not regulated by this mechanism and are also not substrates for RNase T, RNase PH or PAP I. Surprisingly, neither PNPase nor RNase II has any effect on tRNA poly(A) tail length. Our data suggest that the polyadenylation of tRNAs by PAP I likely proceeds in a distributive fashion unlike what is observed with mRNAs.
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Affiliation(s)
| | | | - Sidney R. Kushner
- Department of Genetics, University of Georgia, Athens, GA 30602, USA
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15
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16
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Fang EF, Wong JH, Lin P, Ng TB. Biochemical characterization of the RNA-hydrolytic activity of a pumpkin 2S albumin. FEBS Lett 2010; 584:4089-96. [DOI: 10.1016/j.febslet.2010.08.041] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2010] [Revised: 08/27/2010] [Accepted: 08/27/2010] [Indexed: 02/04/2023]
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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: 263] [Impact Index Per Article: 17.5] [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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