1
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Joshi SHN, Jenkins C, Ulaeto D, Gorochowski TE. Accelerating Genetic Sensor Development, Scale-up, and Deployment Using Synthetic Biology. BIODESIGN RESEARCH 2024; 6:0037. [PMID: 38919711 PMCID: PMC11197468 DOI: 10.34133/bdr.0037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Accepted: 04/23/2024] [Indexed: 06/27/2024] Open
Abstract
Living cells are exquisitely tuned to sense and respond to changes in their environment. Repurposing these systems to create engineered biosensors has seen growing interest in the field of synthetic biology and provides a foundation for many innovative applications spanning environmental monitoring to improved biobased production. In this review, we present a detailed overview of currently available biosensors and the methods that have supported their development, scale-up, and deployment. We focus on genetic sensors in living cells whose outputs affect gene expression. We find that emerging high-throughput experimental assays and evolutionary approaches combined with advanced bioinformatics and machine learning are establishing pipelines to produce genetic sensors for virtually any small molecule, protein, or nucleic acid. However, more complex sensing tasks based on classifying compositions of many stimuli and the reliable deployment of these systems into real-world settings remain challenges. We suggest that recent advances in our ability to precisely modify nonmodel organisms and the integration of proven control engineering principles (e.g., feedback) into the broader design of genetic sensing systems will be necessary to overcome these hurdles and realize the immense potential of the field.
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Affiliation(s)
| | - Christopher Jenkins
- CBR Division, Defence Science and Technology Laboratory, Porton Down, Wiltshire SP4 0JQ, UK
| | - David Ulaeto
- CBR Division, Defence Science and Technology Laboratory, Porton Down, Wiltshire SP4 0JQ, UK
| | - Thomas E. Gorochowski
- School of Biological Sciences, University of Bristol, Bristol BS8 1TQ, UK
- BrisEngBio,
School of Chemistry, University of Bristol, Bristol BS8 1TS, UK
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2
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Narunsky A, Higgs GA, Torres BM, Yu D, de Andrade GB, Kavita K, Breaker RR. The discovery of novel noncoding RNAs in 50 bacterial genomes. Nucleic Acids Res 2024; 52:5152-5165. [PMID: 38647067 PMCID: PMC11109978 DOI: 10.1093/nar/gkae248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Revised: 03/20/2024] [Accepted: 04/18/2024] [Indexed: 04/25/2024] Open
Abstract
Structured noncoding RNAs (ncRNAs) contribute to many important cellular processes involving chemical catalysis, molecular recognition and gene regulation. Few ncRNA classes are broadly distributed among organisms from all three domains of life, but the list of rarer classes that exhibit surprisingly diverse functions is growing. We previously developed a computational pipeline that enables the near-comprehensive identification of structured ncRNAs expressed from individual bacterial genomes. The regions between protein coding genes are first sorted based on length and the fraction of guanosine and cytidine nucleotides. Long, GC-rich intergenic regions are then examined for sequence and structural similarity to other bacterial genomes. Herein, we describe the implementation of this pipeline on 50 bacterial genomes from varied phyla. More than 4700 candidate intergenic regions with the desired characteristics were identified, which yielded 44 novel riboswitch candidates and numerous other putative ncRNA motifs. Although experimental validation studies have yet to be conducted, this rate of riboswitch candidate discovery is consistent with predictions that many hundreds of novel riboswitch classes remain to be discovered among the bacterial species whose genomes have already been sequenced. Thus, many thousands of additional novel ncRNA classes likely remain to be discovered in the bacterial domain of life.
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Affiliation(s)
- Aya Narunsky
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06511, USA
| | - Gadareth A Higgs
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06511, USA
| | - Blake M Torres
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06511, USA
| | - Diane Yu
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06511, USA
| | - Gabriel Belem de Andrade
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06511, USA
| | - Kumari Kavita
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06511, USA
| | - Ronald R Breaker
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06511, USA
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06511, USA
- Howard Hughes Medical Institute, Yale University, New Haven, CT 06511, USA
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3
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Singh RN, Sani RK. Genome-Wide Computational Prediction and Analysis of Noncoding RNAs in Oleidesulfovibrio alaskensis G20. Microorganisms 2024; 12:960. [PMID: 38792789 PMCID: PMC11124144 DOI: 10.3390/microorganisms12050960] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2024] [Revised: 05/03/2024] [Accepted: 05/08/2024] [Indexed: 05/26/2024] Open
Abstract
Noncoding RNAs (ncRNAs) play key roles in the regulation of important pathways, including cellular growth, stress management, signaling, and biofilm formation. Sulfate-reducing bacteria (SRB) contribute to huge economic losses causing microbial-induced corrosion through biofilms on metal surfaces. To effectively combat the challenges posed by SRB, it is essential to understand their molecular mechanisms of biofilm formation. This study aimed to identify ncRNAs in the genome of a model SRB, Oleidesulfovibrio alaskensis G20 (OA G20). Three in silico approaches revealed genome-wide distribution of 37 ncRNAs excluding tRNAs in the OA G20. These ncRNAs belonged to 18 different Rfam families. This study identified riboswitches, sRNAs, RNP, and SRP. The analysis revealed that these ncRNAs could play key roles in the regulation of several pathways of biosynthesis and transport involved in biofilm formation by OA G20. Three sRNAs, Pseudomonas P10, Hammerhead type II, and sX4, which were found in OA G20, are rare and their roles have not been determined in SRB. These results suggest that applying various computational methods could enrich the results and lead to the discovery of additional novel ncRNAs, which could lead to understanding the "rules of life of OA G20" during biofilm formation.
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Affiliation(s)
- Ram Nageena Singh
- Department of Chemical and Biological Engineering, South Dakota Mines, Rapid City, SD 57701, USA;
- 2-Dimensional Materials for Biofilm Engineering, Science and Technology, South Dakota Mines, Rapid City, SD 57701, USA
| | - Rajesh K. Sani
- Department of Chemical and Biological Engineering, South Dakota Mines, Rapid City, SD 57701, USA;
- 2-Dimensional Materials for Biofilm Engineering, Science and Technology, South Dakota Mines, Rapid City, SD 57701, USA
- Data Driven Material Discovery Center for Bioengineering Innovation, South Dakota Mines, Rapid City, SD 57701, USA
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4
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Olenginski LT, Spradlin SF, Batey RT. Flipping the script: Understanding riboswitches from an alternative perspective. J Biol Chem 2024; 300:105730. [PMID: 38336293 PMCID: PMC10907184 DOI: 10.1016/j.jbc.2024.105730] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2023] [Revised: 01/14/2024] [Accepted: 01/19/2024] [Indexed: 02/12/2024] Open
Abstract
Riboswitches are broadly distributed regulatory elements most frequently found in the 5'-leader sequence of bacterial mRNAs that regulate gene expression in response to the binding of a small molecule effector. The occupancy status of the ligand-binding aptamer domain manipulates downstream information in the message that instructs the expression machinery. Currently, there are over 55 validated riboswitch classes, where each class is defined based on the identity of the ligand it binds and/or sequence and structure conservation patterns within the aptamer domain. This classification reflects an "aptamer-centric" perspective that dominates our understanding of riboswitches. In this review, we propose a conceptual framework that groups riboswitches based on the mechanism by which RNA manipulates information directly instructing the expression machinery. This scheme does not replace the established aptamer domain-based classification of riboswitches but rather serves to facilitate hypothesis-driven investigation of riboswitch regulatory mechanisms. Based on current bioinformatic, structural, and biochemical studies of a broad spectrum of riboswitches, we propose three major mechanistic groups: (1) "direct occlusion", (2) "interdomain docking", and (3) "strand exchange". We discuss the defining features of each group, present representative examples of riboswitches from each group, and illustrate how these RNAs couple small molecule binding to gene regulation. While mechanistic studies of the occlusion and docking groups have yielded compelling models for how these riboswitches function, much less is known about strand exchange processes. To conclude, we outline the limitations of our mechanism-based conceptual framework and discuss how critical information within riboswitch expression platforms can inform gene regulation.
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Affiliation(s)
| | | | - Robert T Batey
- Department of Biochemistry, University of Colorado, Boulder, Colorado, USA.
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5
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Salvail H, Balaji A, Roth A, Breaker RR. A spermidine riboswitch class in bacteria exploits a close variant of an aptamer for the enzyme cofactor S-adenosylmethionine. Cell Rep 2023; 42:113571. [PMID: 38096053 PMCID: PMC10853860 DOI: 10.1016/j.celrep.2023.113571] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Revised: 10/16/2023] [Accepted: 11/22/2023] [Indexed: 12/30/2023] Open
Abstract
Natural polyamines such as spermidine and spermine cations have characteristics that make them highly likely to be sensed by riboswitches, such as their general affinity to polyanionic RNA and their broad contributions to cell physiology. Despite previous claims that polyamine riboswitches exist, evidence of their biological functions has remained unconvincing. Here, we report that rare variants of bacterial S-adenosylmethionine-I (SAM-I) riboswitches reject SAM and have adapted to selectively sense spermidine. These spermidine-sensing riboswitch variants are associated with genes whose protein products are directly involved in the production of spermidine and other polyamines. Biochemical and genetic assays demonstrate that representatives of this riboswitch class robustly function as genetic "off" switches, wherein spermidine binding causes premature transcription termination to suppress the expression of polyamine biosynthetic genes. These findings confirm the existence of natural spermidine-sensing riboswitches in bacteria and expand the list of variant riboswitch classes that have adapted to bind different ligands.
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Affiliation(s)
- Hubert Salvail
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06520-8103, USA
| | - Aparaajita Balaji
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06520-8103, USA
| | - Adam Roth
- Howard Hughes Medical Institute, Yale University, New Haven, CT 06520-8103, USA
| | - Ronald R Breaker
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06520-8103, USA; Howard Hughes Medical Institute, Yale University, New Haven, CT 06520-8103, USA; Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520-8103, USA.
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6
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Hamal Dhakal S, Kavita K, Panchapakesan SSS, Roth A, Breaker RR. 8-oxoguanine riboswitches in bacteria detect and respond to oxidative DNA damage. Proc Natl Acad Sci U S A 2023; 120:e2307854120. [PMID: 37748066 PMCID: PMC10556655 DOI: 10.1073/pnas.2307854120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Accepted: 08/25/2023] [Indexed: 09/27/2023] Open
Abstract
Riboswitches rely on structured aptamer domains to selectively sense their target ligands and regulate gene expression. However, some riboswitch aptamers in bacteria carry mutations in their otherwise strictly conserved binding pockets that change ligand specificities. The aptamer domain of a riboswitch class originally found to selectively sense guanine forms a three-stem junction that has since been observed to exploit numerous alterations in its ligand-binding pocket. These rare variants have modified their ligand specificities to sense other purines or purine derivatives, including adenine, 2'-deoxyguanosine (three classes), and xanthine. Herein, we report the characteristics of a rare variant that is narrowly distributed in the Paenibacillaceae family of bacteria. Known representatives are always associated with genes encoding 8-oxoguanine deaminase. As predicted from this gene association, these variant riboswitches tightly bind 8-oxoguanine (8-oxoG), strongly discriminate against other purine derivatives, and function as genetic "ON" switches. Following exposure of cells to certain oxidative stresses, a representative 8-oxoG riboswitch activates gene expression, likely caused by the accumulation of 8-oxoG due to oxidative damage to G nucleobases in DNA, RNA, and the nucleotide pool. Furthermore, an engineered version of the variant aptamer was prepared that exhibits specificity for 8-oxoadenine, further demonstrating that RNA aptamers can acquire mutations that expand their ability to detect and respond to oxidative damage.
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Affiliation(s)
- Siddhartha Hamal Dhakal
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT06511-8103
| | - Kumari Kavita
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT06511-8103
| | | | - Adam Roth
- HHMI, Yale University, New Haven, CT06511-8103
| | - Ronald R. Breaker
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT06511-8103
- HHMI, Yale University, New Haven, CT06511-8103
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT06511-8103
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7
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Kavita K, Breaker RR. Discovering riboswitches: the past and the future. Trends Biochem Sci 2023; 48:119-141. [PMID: 36150954 PMCID: PMC10043782 DOI: 10.1016/j.tibs.2022.08.009] [Citation(s) in RCA: 51] [Impact Index Per Article: 51.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2022] [Revised: 08/18/2022] [Accepted: 08/26/2022] [Indexed: 01/25/2023]
Abstract
Riboswitches are structured noncoding RNA domains used by many bacteria to monitor the concentrations of target ligands and regulate gene expression accordingly. In the past 20 years over 55 distinct classes of natural riboswitches have been discovered that selectively sense small molecules or elemental ions, and thousands more are predicted to exist. Evidence suggests that some riboswitches might be direct descendants of the RNA-based sensors and switches that were likely present in ancient organisms before the evolutionary emergence of proteins. We provide an overview of the current state of riboswitch research, focusing primarily on the discovery of riboswitches, and speculate on the major challenges facing researchers in the field.
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Affiliation(s)
- Kumari Kavita
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06520-8103, USA
| | - Ronald R Breaker
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06520-8103, USA; Howard Hughes Medical Institute, Yale University, New Haven, CT 06520-8103, USA; Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520-8103, USA.
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8
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Ghazimoradi MH, Karimpour-Fard N, Babashah S. The Promising Role of Non-Coding RNAs as Biomarkers and Therapeutic Targets for Leukemia. Genes (Basel) 2023; 14:131. [PMID: 36672872 PMCID: PMC9859176 DOI: 10.3390/genes14010131] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 12/02/2022] [Accepted: 12/05/2022] [Indexed: 01/05/2023] Open
Abstract
Early-stage leukemia identification is crucial for effective disease management and leads to an improvement in the survival of leukemia patients. Approaches based on cutting-edge biomarkers with excellent accuracy in body liquids provide patients with the possibility of early diagnosis with high sensitivity and specificity. Non-coding RNAs have recently received a great deal of interest as possible biomarkers in leukemia due to their participation in crucial oncogenic processes such as proliferation, differentiation, invasion, apoptosis, and their availability in body fluids. Recent studies have revealed a strong correlation between leukemia and the deregulated non-coding RNAs. On this basis, these RNAs are also great therapeutic targets. Based on these advantages, we tried to review the role of non-coding RNAs in leukemia. Here, the significance of several non-coding RNA types in leukemia is highlighted, and their potential roles as diagnostic, prognostic, and therapeutic targets are covered.
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Affiliation(s)
- Mohammad H. Ghazimoradi
- Department of Molecular Genetics, Faculty of Biological Sciences, Tarbiat Modares University, Tehran 1411713116, Iran
| | - Naeim Karimpour-Fard
- Department of Pharmacoeconomics and Pharmaceutical Administration, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran 1417614411, Iran
| | - Sadegh Babashah
- Department of Molecular Genetics, Faculty of Biological Sciences, Tarbiat Modares University, Tehran 1411713116, Iran
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9
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Sherlock ME, Higgs G, Yu D, Widner DL, White NA, Sudarsan N, Sadeeshkumar H, Perkins KR, Mirihana Arachchilage G, Malkowski SN, King CG, Harris KA, Gaffield G, Atilho RM, Breaker RR. Architectures and complex functions of tandem riboswitches. RNA Biol 2022; 19:1059-1076. [PMID: 36093908 PMCID: PMC9481103 DOI: 10.1080/15476286.2022.2119017] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Riboswitch architectures that involve the binding of a single ligand to a single RNA aptamer domain result in ordinary dose-response curves that require approximately a 100-fold change in ligand concentration to cover nearly the full dynamic range for gene regulation. However, by using multiple riboswitches or aptamer domains in tandem, these ligand-sensing structures can produce additional, complex gene control outcomes. In the current study, we have computationally searched for tandem riboswitch architectures in bacteria to provide a more complete understanding of the diverse biological and biochemical functions of gene control elements that are made exclusively of RNA. Numerous different arrangements of tandem homologous riboswitch architectures are exploited by bacteria to create more ‘digital’ gene control devices, which operate over a narrower ligand concentration range. Also, two heterologous riboswitch aptamers are sometimes employed to create two-input Boolean logic gates with various types of genetic outputs. These findings illustrate the sophisticated genetic decisions that can be made by using molecular sensors and switches based only on RNA.
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Affiliation(s)
- Madeline E. Sherlock
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
- Department of Biochemistry and Molecular Genetics, University of Colorado, Anschutz Medical Campus, Research-1S, Aurora, CO, USA
| | - Gadareth Higgs
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT, USA
| | - Diane Yu
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT, USA
| | - Danielle L. Widner
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Neil A. White
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT, USA
| | | | - Harini Sadeeshkumar
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT, USA
| | - Kevin R. Perkins
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT, USA
| | - Gayan Mirihana Arachchilage
- Howard Hughes Medical Institute, Yale University, New Haven, CT, USA
- PTC Therapeutics, Inc, South Plainfield, NJ, USA
| | | | - Christopher G. King
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | | | - Glenn Gaffield
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT, USA
| | - Ruben M. Atilho
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT, USA
| | - Ronald R. Breaker
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT, USA
- Howard Hughes Medical Institute, Yale University, New Haven, CT, USA
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10
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Vogt G. Environmental Adaptation of Genetically Uniform Organisms with the Help of Epigenetic Mechanisms-An Insightful Perspective on Ecoepigenetics. EPIGENOMES 2022; 7:1. [PMID: 36648862 PMCID: PMC9844400 DOI: 10.3390/epigenomes7010001] [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: 11/21/2022] [Revised: 12/11/2022] [Accepted: 12/15/2022] [Indexed: 12/28/2022] Open
Abstract
Organisms adapt to different environments by selection of the most suitable phenotypes from the standing genetic variation or by phenotypic plasticity, the ability of single genotypes to produce different phenotypes in different environments. Because of near genetic identity, asexually reproducing populations are particularly suitable for the investigation of the potential and molecular underpinning of the latter alternative in depth. Recent analyses on the whole-genome scale of differently adapted clonal animals and plants demonstrated that epigenetic mechanisms such as DNA methylation, histone modifications and non-coding RNAs are among the molecular pathways supporting phenotypic plasticity and that epigenetic variation is used to stably adapt to different environments. Case studies revealed habitat-specific epigenetic fingerprints that were maintained over subsequent years pointing at the existence of epigenetic ecotypes. Environmentally induced epimutations and corresponding gene expression changes provide an ideal means for fast and directional adaptation to changing or new conditions, because they can synchronously alter phenotypes in many population members. Because microorganisms inclusive of human pathogens also exploit epigenetically mediated phenotypic variation for environmental adaptation, this phenomenon is considered a universal biological principle. The production of different phenotypes from the same DNA sequence in response to environmental cues by epigenetic mechanisms also provides a mechanistic explanation for the "general-purpose genotype hypothesis" and the "genetic paradox of invasions".
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Affiliation(s)
- Günter Vogt
- Faculty of Biosciences, University of Heidelberg, Im Neuenheimer Feld 234, 69120 Heidelberg, Germany
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11
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González-Tortuero E, Anthon C, Havgaard JH, Geissler AS, Breüner A, Hjort C, Gorodkin J, Seemann SE. The Bacillaceae-1 RNA motif comprises two distinct classes. Gene 2022; 841:146756. [PMID: 35905857 DOI: 10.1016/j.gene.2022.146756] [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: 05/16/2022] [Revised: 06/10/2022] [Accepted: 07/24/2022] [Indexed: 11/04/2022]
Abstract
Non-coding RNAs are key regulatory players in bacteria. Many computationally predicted non-coding RNAs, however, lack functional associations. An example is the Bacillaceae-1 RNA motif, whose Rfam model consists of two hairpin loops. We find the motif conserved in nine of 13 non-pathogenic strains of the genus Bacillus but only in one pathogenic strain. To elucidate functional characteristics, we studied 118 hits of the Rfam model in 11 Bacillus spp. and found two distinct classes based on the ensemble diversity of their RNA secondary structure and the genomic context concerning the ribosomal RNA (rRNA) cluster. Forty hits are associated with the rRNA cluster, of which all 19 hits upstream flanking of 16S rRNA have a reverse complementary structure of low structural diversity. Fifty-two hits have large ensemble diversity, of which 38 are located between two coding genes. For eight hits in Bacillus subtilis, we investigated public expression data under various conditions and observed either the forward or the reverse complementary motif expressed. Five hits are associated with the rRNA cluster. Four of them are located upstream of the 16S rRNA and are not transcriptionally active, but instead, their reverse complements with low structural diversity are expressed together with the rRNA cluster. The three other hits are located between two coding genes in non-conserved genomic loci. Two of them are independently expressed from their surrounding genes and are structurally diverse. In summary, we found that Bacillaceae-1 RNA motifs upstream flanking of ribosomal RNA clusters tend to have one stable structure with the reverse complementary motif expressed in B. subtilis. In contrast, a subgroup of intergenic motifs has the thermodynamic potential for structural switches.
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Affiliation(s)
- Enrique González-Tortuero
- Center for non-coding RNA in Technology and Health (RTH), Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Christian Anthon
- Center for non-coding RNA in Technology and Health (RTH), Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Jakob H Havgaard
- Center for non-coding RNA in Technology and Health (RTH), Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Adrian S Geissler
- Center for non-coding RNA in Technology and Health (RTH), Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg, Denmark
| | | | | | - Jan Gorodkin
- Center for non-coding RNA in Technology and Health (RTH), Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg, Denmark.
| | - Stefan E Seemann
- Center for non-coding RNA in Technology and Health (RTH), Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg, Denmark.
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12
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Mahendran G, Jayasinghe OT, Thavakumaran D, Arachchilage GM, Silva GN. Key players in regulatory RNA realm of bacteria. Biochem Biophys Rep 2022; 30:101276. [PMID: 35592614 PMCID: PMC9111926 DOI: 10.1016/j.bbrep.2022.101276] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Revised: 04/30/2022] [Accepted: 05/04/2022] [Indexed: 11/30/2022] Open
Abstract
Precise regulation of gene expression is crucial for living cells to adapt for survival in diverse environmental conditions. Among the common cellular regulatory mechanisms, RNA-based regulators play a key role in all domains of life. Discovery of regulatory RNAs have made a paradigm shift in molecular biology as many regulatory functions of RNA have been identified beyond its canonical roles as messenger, ribosomal and transfer RNA. In the complex regulatory RNA network, riboswitches, small RNAs, and RNA thermometers can be identified as some of the key players. Herein, we review the discovery, mechanism, and potential therapeutic use of these classes of regulatory RNAs mainly found in bacteria. Being highly adaptive organisms that inhabit a broad range of ecological niches, bacteria have adopted tight and rapid-responding gene regulation mechanisms. This review aims to highlight how bacteria utilize versatile RNA structures and sequences to build a sophisticated gene regulation network. The three major classes of prokaryotic ncRNAs and their characterized mechanisms of operation in gene regulation. sRNAs emerging as major players in global gene regulatory networks. Riboswitch mediated gene control mechanisms through on/off switches in response to ligand binding. RNA thermo sensors for temperature-dependent gene expression. Therapeutic importance of ncRNAs and computational approaches involved in the discovery of ncRNAs.
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Affiliation(s)
- Gowthami Mahendran
- Department of Chemistry, University of Colombo, Colombo, Sri Lanka
- Department of Chemistry and Biochemistry, University of Notre Dame, IN, 46556, USA
| | - Oshadhi T. Jayasinghe
- Department of Chemistry, University of Colombo, Colombo, Sri Lanka
- Department of Biochemistry and Molecular Biology, Center for RNA Molecular Biology, Pennsylvania State University, University Park, PA, 16802, USA
| | - Dhanushika Thavakumaran
- Department of Chemistry, University of Colombo, Colombo, Sri Lanka
- Department of Chemistry and Biochemistry, University of Notre Dame, IN, 46556, USA
| | - Gayan Mirihana Arachchilage
- Howard Hughes Medical Institute, Yale University, New Haven, CT, 06520-8103, USA
- PTC Therapeutics Inc, South Plainfield, NJ, 07080, USA
| | - Gayathri N. Silva
- Department of Chemistry, University of Colombo, Colombo, Sri Lanka
- Corresponding author.
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13
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Bonidia RP, Santos APA, de Almeida BLS, Stadler PF, da Rocha UN, Sanches DS, de Carvalho ACPLF. BioAutoML: automated feature engineering and metalearning to predict noncoding RNAs in bacteria. Brief Bioinform 2022; 23:6618238. [PMID: 35753697 PMCID: PMC9294424 DOI: 10.1093/bib/bbac218] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Revised: 05/06/2022] [Accepted: 05/09/2022] [Indexed: 01/19/2023] Open
Abstract
Recent technological advances have led to an exponential expansion of biological sequence data and extraction of meaningful information through Machine Learning (ML) algorithms. This knowledge has improved the understanding of mechanisms related to several fatal diseases, e.g. Cancer and coronavirus disease 2019, helping to develop innovative solutions, such as CRISPR-based gene editing, coronavirus vaccine and precision medicine. These advances benefit our society and economy, directly impacting people’s lives in various areas, such as health care, drug discovery, forensic analysis and food processing. Nevertheless, ML-based approaches to biological data require representative, quantitative and informative features. Many ML algorithms can handle only numerical data, and therefore sequences need to be translated into a numerical feature vector. This process, known as feature extraction, is a fundamental step for developing high-quality ML-based models in bioinformatics, by allowing the feature engineering stage, with design and selection of suitable features. Feature engineering, ML algorithm selection and hyperparameter tuning are often manual and time-consuming processes, requiring extensive domain knowledge. To deal with this problem, we present a new package: BioAutoML. BioAutoML automatically runs an end-to-end ML pipeline, extracting numerical and informative features from biological sequence databases, using the MathFeature package, and automating the feature selection, ML algorithm(s) recommendation and tuning of the selected algorithm(s) hyperparameters, using Automated ML (AutoML). BioAutoML has two components, divided into four modules: (1) automated feature engineering (feature extraction and selection modules) and (2) Metalearning (algorithm recommendation and hyper-parameter tuning modules). We experimentally evaluate BioAutoML in two different scenarios: (i) prediction of the three main classes of noncoding RNAs (ncRNAs) and (ii) prediction of the eight categories of ncRNAs in bacteria, including housekeeping and regulatory types. To assess BioAutoML predictive performance, it is experimentally compared with two other AutoML tools (RECIPE and TPOT). According to the experimental results, BioAutoML can accelerate new studies, reducing the cost of feature engineering processing and either keeping or improving predictive performance. BioAutoML is freely available at https://github.com/Bonidia/BioAutoML.
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Affiliation(s)
- Robson P Bonidia
- Institute of Mathematics and Computer Sciences, University of São Paulo, São Carlos 13566-590, Brazil
| | - Anderson P Avila Santos
- Institute of Mathematics and Computer Sciences, University of São Paulo, São Carlos 13566-590, Brazil.,Department of Environmental Microbiology, Helmholtz Centre for Environmental Research-UFZ GmbH, Leipzig, Saxony, Germany
| | - Breno L S de Almeida
- Institute of Mathematics and Computer Sciences, University of São Paulo, São Carlos 13566-590, Brazil
| | - Peter F Stadler
- Department of Computer Science and Interdisciplinary Center of Bioinformatics, University of Leipzig, Leipzig, Saxony, Germany
| | - Ulisses N da Rocha
- Department of Environmental Microbiology, Helmholtz Centre for Environmental Research-UFZ GmbH, Leipzig, Saxony, Germany
| | - Danilo S Sanches
- Department of Computer Science, Federal University of Technology - Paraná, UTFPR, Cornélio Procópio 86300-000, Brazil
| | - André C P L F de Carvalho
- Institute of Mathematics and Computer Sciences, University of São Paulo, São Carlos 13566-590, Brazil
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14
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Diallo I, Ho J, Lalaouna D, Massé E, Provost P. RNA Sequencing Unveils Very Small RNAs With Potential Regulatory Functions in Bacteria. Front Mol Biosci 2022; 9:914991. [PMID: 35720117 PMCID: PMC9203972 DOI: 10.3389/fmolb.2022.914991] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Accepted: 05/02/2022] [Indexed: 12/21/2022] Open
Abstract
RNA sequencing (RNA-seq) is the gold standard for the discovery of small non-coding RNAs. Following a long-standing approach, reads shorter than 16 nucleotides (nt) are removed from the small RNA sequencing libraries or datasets. The serendipitous discovery of an eukaryotic 12 nt-long RNA species capable of modulating the microRNA from which they derive prompted us to challenge this dogma and, by expanding the window of RNA sizes down to 8 nt, to confirm the existence of functional very small RNAs (vsRNAs <16 nt). Here we report the detailed profiling of vsRNAs in Escherichia coli, E. coli-derived outer membrane vesicles (OMVs) and five other bacterial strains (Pseudomonas aeruginosa PA7, P. aeruginosa PAO1, Salmonella enterica serovar Typhimurium 14028S, Legionella pneumophila JR32 Philadelphia-1 and Staphylococcus aureus HG001). vsRNAs of 8–15 nt in length [RNAs (8-15 nt)] were found to be more abundant than RNAs of 16–30 nt in length [RNAs (16–30 nt)]. vsRNA biotypes were distinct and varied within and across bacterial species and accounted for one third of reads identified in the 8–30 nt window. The tRNA-derived fragments (tRFs) have appeared as a major biotype among the vsRNAs, notably Ile-tRF and Ala-tRF, and were selectively loaded in OMVs. tRF-derived vsRNAs appear to be thermodynamically stable with at least 2 G-C basepairs and stem-loop structure. The analyzed tRF-derived vsRNAs are predicted to target several human host mRNAs with diverse functions. Bacterial vsRNAs and OMV-derived vsRNAs could be novel players likely modulating the intricate relationship between pathogens and their hosts.
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Affiliation(s)
- Idrissa Diallo
- CHU de Québec Research Center/CHUL Pavilion, Department of Microbiology, Infectious Diseases and Immunology, Faculty of Medicine, Université Laval, Quebec City, QC, Canada
| | - Jeffrey Ho
- CHU de Québec Research Center/CHUL Pavilion, Department of Microbiology, Infectious Diseases and Immunology, Faculty of Medicine, Université Laval, Quebec City, QC, Canada
| | - David Lalaouna
- CRCHUS, RNA Group, Department of Biochemistry and Functional Genomics, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Eric Massé
- CRCHUS, RNA Group, Department of Biochemistry and Functional Genomics, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Patrick Provost
- CHU de Québec Research Center/CHUL Pavilion, Department of Microbiology, Infectious Diseases and Immunology, Faculty of Medicine, Université Laval, Quebec City, QC, Canada
- *Correspondence: Patrick Provost,
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15
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Abstract
More than 55 distinct classes of riboswitches that respond to small metabolites or elemental ions have been experimentally validated to date. The ligands sensed by these riboswitches are biased in favor of fundamental compounds or ions that are likely to have been relevant to ancient forms of life, including those that might have populated the "RNA World", which is a proposed biochemical era that predates the evolutionary emergence of DNA and proteins. In the following text, I discuss the various types of ligands sensed by some of the most common riboswitches present in modern bacterial cells and consider implications for ancient biological processes centered on the proven capabilities of these RNA-based sensors. Although most major biochemical aspects of metabolism are represented by known riboswitch classes, there are striking sensory gaps in some key areas. These gaps could reveal weaknesses in the performance capabilities of RNA that might have hampered RNA World evolution, or these could highlight opportunities to discover additional riboswitch classes that sense essential metabolites.
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Affiliation(s)
- Ronald R. Breaker
- Corresponding Author: Ronald R. Breaker - Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06520-8103, United States; Phone: 203-432-9389; , Twitter: @RonBreaker
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16
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Brewer KI, Gaffield GJ, Puri M, Breaker RR. DIMPL: a bioinformatics pipeline for the discovery of structured noncoding RNA motifs in bacteria. Bioinformatics 2021; 38:533-535. [PMID: 34524415 PMCID: PMC8723152 DOI: 10.1093/bioinformatics/btab624] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 05/07/2021] [Accepted: 09/10/2021] [Indexed: 02/03/2023] Open
Abstract
SUMMARY Recent efforts to identify novel bacterial structured noncoding RNA (ncRNA) motifs through searching long, GC-rich intergenic regions (IGRs) have revealed several new classes, including the recently validated HMP-PP riboswitch. The DIMPL (Discovery of Intergenic Motifs PipeLine) discovery pipeline described herein enables rapid extraction and selection of bacterial IGRs that are enriched for structured ncRNAs. Moreover, DIMPL automates the subsequent computational steps necessary for their functional identification. AVAILABILITY AND IMPLEMENTATION The DIMPL pipeline is freely available as a Docker image with an accompanying set of Jupyter notebooks. Full instructions for download and use are available at https://github.com/breakerlab/dimpl. SUPPLEMENTARY INFORMATION Supplementary data are available at Bioinformatics online.
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Affiliation(s)
- Kenneth I Brewer
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520-8103, USA
| | - Glenn J Gaffield
- Howard Hughes Medical Institute, Yale University, New Haven, CT 06520-8103, USA
| | - Malavika Puri
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06520-8103, USA
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17
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Ariza-Mateos A, Nuthanakanti A, Serganov A. Riboswitch Mechanisms: New Tricks for an Old Dog. BIOCHEMISTRY (MOSCOW) 2021; 86:962-975. [PMID: 34488573 DOI: 10.1134/s0006297921080071] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Discovered almost twenty years ago, riboswitches turned out to be one of the most common regulatory systems in bacteria, with representatives found in eukaryotes and archaea. Unlike many other regulatory elements, riboswitches are entirely composed of RNA and capable of modulating expression of genes by direct binding of small cellular molecules. While bacterial riboswitches had been initially thought to control production of enzymes and transporters associated with small organic molecules via feedback regulatory circuits, later findings identified riboswitches directing expression of a wide range of genes and responding to various classes of molecules, including ions, signaling molecules, and others. The 5'-untranslated mRNA regions host a vast majority of riboswitches, which modulate transcription or translation of downstream genes through conformational rearrangements in the ligand-sensing domains and adjacent expression-controlling platforms. Over years, the repertoire of regulatory mechanisms employed by riboswitches has greatly expanded; most recent studies have highlighted the importance of alternative mechanisms, such as RNA degradation, for the riboswitch-mediated genetic circuits. This review discusses the plethora of bacterial riboswitch mechanisms and illustrates how riboswitches utilize different features and approaches to elicit various regulatory responses.
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Affiliation(s)
- Ascensión Ariza-Mateos
- Department of Biochemistry and Molecular Pharmacology, New York University Grossman School of Medicine, New York, NY 10016, USA
| | - Ashok Nuthanakanti
- Department of Biochemistry and Molecular Pharmacology, New York University Grossman School of Medicine, New York, NY 10016, USA
| | - Alexander Serganov
- Department of Biochemistry and Molecular Pharmacology, New York University Grossman School of Medicine, New York, NY 10016, USA.
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18
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Thairu MW, Meduri VRS, Degnan PH, Hansen AK. Natural selection shapes maintenance of orthologous sRNAs in divergent host-restricted bacterial genomes. Mol Biol Evol 2021; 38:4778-4791. [PMID: 34213555 PMCID: PMC8557413 DOI: 10.1093/molbev/msab202] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Historically it has been difficult to study the evolution of bacterial small RNAs (sRNAs) across distantly related species. For example, identifying homologs of sRNAs is often difficult in genomes that have undergone multiple structural rearrangements. Also, some types of regulatory sRNAs evolve at rapid rates. The high degree of genomic synteny among divergent host-restricted bacterial lineages, including intracellular symbionts, is conducive to sRNA maintenance and homolog identification. In turn, symbiont genomes can provide us with novel insights into sRNA evolution. Here, we examine the sRNA expression profile of the obligate symbiont of psyllids, Carsonella ruddii, which has one of the smallest cellular genomes described. Using RNA-seq, we identified 36 and 32 antisense sRNAs (asRNAs) expressed by Carsonella from the psyllids Bactericera cockerelli (Carsonella-BC) and Diaphorina citri (Carsonella-DC), respectively. The majority of these asRNAs were associated with genes that are involved in essential amino acid biosynthetic pathways. Eleven of the asRNAs were conserved in both Carsonella lineages and the majority were maintained by selection. Notably, five of the corresponding coding sequences are also the targets of conserved asRNAs in a distantly related insect symbiont, Buchnera. We detected differential expression of two asRNAs for genes involved in arginine and leucine biosynthesis occurring between two distinct Carsonella-BC life stages. Using asRNAs identified in Carsonella, Buchnera, and Profftella which are all endosymbionts, and Escherichia coli, we determined that regions upstream of these asRNAs encode unique conserved patterns of AT/GC richness, GC skew, and sequence motifs which may be involved in asRNA regulation.
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Affiliation(s)
- Margaret W Thairu
- Department of Entomology, University of California, Riverside, Riverside, CA.,Department of Bacteriology, University of Wisconsin, Madison, Madison, WI
| | | | - Patrick H Degnan
- Department of Microbiology and Plant Pathology, University of California, Riverside, Riverside, California, USA
| | - Allison K Hansen
- Department of Entomology, University of California, Riverside, Riverside, CA
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19
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Gao W, Jones TA, Rivas E. Discovery of 17 conserved structural RNAs in fungi. Nucleic Acids Res 2021; 49:6128-6143. [PMID: 34086938 PMCID: PMC8216456 DOI: 10.1093/nar/gkab355] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 03/25/2021] [Accepted: 04/21/2021] [Indexed: 11/13/2022] Open
Abstract
Many non-coding RNAs with known functions are structurally conserved: their intramolecular secondary and tertiary interactions are maintained across evolutionary time. Consequently, the presence of conserved structure in multiple sequence alignments can be used to identify candidate functional non-coding RNAs. Here, we present a bioinformatics method that couples iterative homology search with covariation analysis to assess whether a genomic region has evidence of conserved RNA structure. We used this method to examine all unannotated regions of five well-studied fungal genomes (Saccharomyces cerevisiae, Candida albicans, Neurospora crassa, Aspergillus fumigatus, and Schizosaccharomyces pombe). We identified 17 novel structurally conserved non-coding RNA candidates, which include four H/ACA box small nucleolar RNAs, four intergenic RNAs and nine RNA structures located within the introns and untranslated regions (UTRs) of mRNAs. For the two structures in the 3' UTRs of the metabolic genes GLY1 and MET13, we performed experiments that provide evidence against them being eukaryotic riboswitches.
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Affiliation(s)
- William Gao
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, USA
| | - Thomas A Jones
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, USA
- Howard Hughes Medical Institute, Harvard University, Cambridge, USA
| | - Elena Rivas
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, USA
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20
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Biswas R, Ghosh D, Dutta B, Halder U, Goswami P, Bandopadhyay R. Potential Non-coding RNAs from Microorganisms and their Therapeutic Use in the Treatment of Different Human Cancers. Curr Gene Ther 2021; 21:207-215. [PMID: 33390136 DOI: 10.2174/1566523220999201230204814] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 11/27/2020] [Accepted: 12/03/2020] [Indexed: 11/22/2022]
Abstract
Cancer therapy describes the treatment of cancer, often with surgery, chemotherapy, and radiotherapy. Additionally, RNA interference (RNAi) is likely to be considered a new emerging, alternative therapeutic approach for silencing/targeting cancer-related genes. RNAi can exert antiproliferative and proapoptotic effects by targeting functional carcinogenic molecules or knocking down gene products of cancer-related genes. However, in contrast to conventional cancer therapies, RNAi based therapy seems to have fewer side effects. Transcription signal sequence and conserved sequence analysis-showed that microorganisms could be a potent source of non-coding RNAs. This review concluded that mapping of RNAi mechanism and RNAi based drug delivery approaches is expected to lead a better prospective of cancer therapy.
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Affiliation(s)
- Raju Biswas
- UGC-Center of Advanced study, Department of Botany, The University of Burdwan, Golapbag, Burdwan-713104, West Bengal, India
| | - Dipanjana Ghosh
- UGC-Center of Advanced study, Department of Botany, The University of Burdwan, Golapbag, Burdwan-713104, West Bengal, India
| | - Bhramar Dutta
- UGC-Center of Advanced study, Department of Botany, The University of Burdwan, Golapbag, Burdwan-713104, West Bengal, India
| | - Urmi Halder
- UGC-Center of Advanced study, Department of Botany, The University of Burdwan, Golapbag, Burdwan-713104, West Bengal, India
| | - Prittam Goswami
- Haldia Institute of Technology, HIT College Rd, Kshudiram Nagar, Haldia-721657, West Bengal, India
| | - Rajib Bandopadhyay
- UGC-Center of Advanced study, Department of Botany, The University of Burdwan, Golapbag, Burdwan-713104, West Bengal, India
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21
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Brewer KI, Greenlee EB, Higgs G, Yu D, Mirihana Arachchilage G, Chen X, King N, White N, Breaker RR. Comprehensive discovery of novel structured noncoding RNAs in 26 bacterial genomes. RNA Biol 2021; 18:2417-2432. [PMID: 33970790 PMCID: PMC8632094 DOI: 10.1080/15476286.2021.1917891] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/30/2022] Open
Abstract
Comparative sequence analysis methods are highly effective for uncovering novel classes of structured noncoding RNAs (ncRNAs) from bacterial genomic DNA sequence datasets. Previously, we developed a computational pipeline to more comprehensively identify structured ncRNA representatives from individual bacterial genomes. This search process exploits the fact that genomic regions serving as templates for the transcription of structured RNAs tend to be present in longer than average noncoding 'intergenic regions' (IGRs) that are enriched in G and C nucleotides compared to the remainder of the genome. In the present study, we apply this computational pipeline to identify structured ncRNA candidates from 26 diverse bacterial species. Numerous novel structured ncRNA motifs were discovered, including several riboswitch candidates, one whose ligand has been identified and others that have yet to be experimentally validated. Our findings support recent predictions that hundreds of novel ribo-switch classes and other ncRNAs remain undiscovered among the limited number of bacterial species whose genomes have been completely sequenced.
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Affiliation(s)
- Kenneth I Brewer
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Etienne B Greenlee
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT, USA
| | - Gadareth Higgs
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT, USA
| | - Diane Yu
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT, USA
| | | | - Xi Chen
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Nicholas King
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT, USA
| | - Neil White
- Howard Hughes Medical Institute, Yale University, New Haven, CT, USA
| | - Ronald R Breaker
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA.,Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT, USA.,Howard Hughes Medical Institute, Yale University, New Haven, CT, USA
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22
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Liu B, Thippabhotla S, Zhang J, Zhong C. DRAGoM: Classification and Quantification of Noncoding RNA in Metagenomic Data. Front Genet 2021; 12:669495. [PMID: 34025724 PMCID: PMC8131839 DOI: 10.3389/fgene.2021.669495] [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: 02/18/2021] [Accepted: 03/23/2021] [Indexed: 12/21/2022] Open
Abstract
Noncoding RNAs (ncRNAs) play important regulatory and functional roles in microorganisms, such as regulation of gene expression, signaling, protein synthesis, and RNA processing. Hence, their classification and quantification are central tasks toward the understanding of the function of the microbial community. However, the majority of the current metagenomic sequencing technologies generate short reads, which may contain only a partial secondary structure that complicates ncRNA homology detection. Meanwhile, de novo assembly of the metagenomic sequencing data remains challenging for complex communities. To tackle these challenges, we developed a novel algorithm called DRAGoM (Detection of RNA using Assembly Graph from Metagenomic data). DRAGoM first constructs a hybrid graph by merging an assembly string graph and an assembly de Bruijn graph. Then, it classifies paths in the hybrid graph and their constituent readsinto differentncRNA families based on both sequence and structural homology. Our benchmark experiments show that DRAGoMcan improve the performance and robustness over traditional approaches on the classification and quantification of a wide class of ncRNA families.
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Affiliation(s)
- Ben Liu
- Department of Electrical Engineering and Computer Science, The University of Kansas, Lawrence, KS, United States
| | - Sirisha Thippabhotla
- Department of Electrical Engineering and Computer Science, The University of Kansas, Lawrence, KS, United States
| | - Jun Zhang
- Division of Medical Oncology, Department of Internal Medicine, University of Kansas Medical Center, Kansas City, KS, United States.,Department of Cancer Biology, University of Kansas Medical Center, Kansas City, KS, United States
| | - Cuncong Zhong
- Department of Electrical Engineering and Computer Science, The University of Kansas, Lawrence, KS, United States.,Bioengineering Program, The University of Kansas, Lawrence, KS, United States.,Center for Computational Biology, The University of Kansas, Lawrence, KS, United States
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23
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Manna S, Truong J, Hammond MC. Guanidine Biosensors Enable Comparison of Cellular Turn-on Kinetics of Riboswitch-Based Biosensor and Reporter. ACS Synth Biol 2021; 10:566-578. [PMID: 33646758 PMCID: PMC7985839 DOI: 10.1021/acssynbio.0c00583] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Indexed: 12/30/2022]
Abstract
Cell-based sensors are useful for many synthetic biology applications, including regulatory circuits, metabolic engineering, and diagnostics. While considerable research efforts have been made toward recognizing new target ligands and increasing sensitivity, the analysis and optimization of turn-on kinetics is often neglected. For example, to our knowledge there has been no systematic study that compared the performance of a riboswitch-based biosensor versus reporter for the same ligand. In this study, we show the development of RNA-based fluorescent (RBF) biosensors for guanidine, a common chaotropic agent that is a precursor to both fertilizer and explosive compounds. Guanidine is cell permeable and nontoxic to E. coli at millimolar concentrations, which in contrast to prior studies enabled direct activation of the riboswitch-based biosensor and corresponding reporter with ligand addition to cells. Our results reveal that the biosensors activate fluorescence in the cell within 4 min of guanidine treatment, which is at least 15 times faster than a reporter derived from the same riboswitch, and this rapid sensing activity is maintained for up to 1.6 weeks. Together, this study describes the design of two new biosensor topologies and showcases the advantages of RBF biosensors for monitoring dynamic processes in cell biology, biotechnology, and synthetic biology.
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Affiliation(s)
- Sudeshna Manna
- Department
of Chemistry, University of Utah, Salt Lake City, Utah 84112, United States
- Henry
Eyring Center for Cell & Genome Science, University of Utah, Salt Lake
City, Utah 84112, United States
| | - Johnny Truong
- Department
of Chemistry, University of Utah, Salt Lake City, Utah 84112, United States
- Henry
Eyring Center for Cell & Genome Science, University of Utah, Salt Lake
City, Utah 84112, United States
- Department
of Chemistry, University of California, Berkeley, California 94720, United States
| | - Ming C. Hammond
- Department
of Chemistry, University of Utah, Salt Lake City, Utah 84112, United States
- Henry
Eyring Center for Cell & Genome Science, University of Utah, Salt Lake
City, Utah 84112, United States
- Department
of Chemistry, University of California, Berkeley, California 94720, United States
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24
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Panchapakesan SSS, Corey L, Malkowski SN, Higgs G, Breaker RR. A second riboswitch class for the enzyme cofactor NAD . RNA (NEW YORK, N.Y.) 2021; 27:99-105. [PMID: 33087526 PMCID: PMC7749635 DOI: 10.1261/rna.077891.120] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Accepted: 10/19/2020] [Indexed: 06/01/2023]
Abstract
A bacterial noncoding RNA motif almost exclusively associated with pnuC genes was uncovered using comparative sequence analysis. Some PnuC proteins are known to transport nicotinamide riboside (NR), which is a component of the ubiquitous and abundant enzyme cofactor nicotinamide adenine dinucleotide (NAD+). Thus, we speculated that the newly found "pnuC motif" RNAs might function as aptamers for a novel class of NAD+-sensing riboswitches. RNA constructs that encompass the conserved nucleotides and secondary structure features that define the motif indeed selectively bind NAD+, nicotinamide mononucleotide (NMN), and NR. Mutations that disrupt strictly conserved nucleotides of the aptamer also disrupt ligand binding. These bioinformatic and biochemical findings indicate that pnuC motif RNAs are likely members of a second riboswitch class that regulates gene expression in response to NAD+ binding.
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Affiliation(s)
- Shanker S S Panchapakesan
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, Connecticut 06520-8103, USA
| | - Lukas Corey
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, Connecticut 06520-8103, USA
| | - Sarah N Malkowski
- Department of Chemistry, Yale University, New Haven, Connecticut 06520-8103, USA
| | - Gadareth Higgs
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, Connecticut 06520-8103, USA
| | - Ronald R Breaker
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, Connecticut 06520-8103, USA
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520-8103, USA
- Howard Hughes Medical Institute, Yale University, New Haven, Connecticut 06520-8103, USA
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25
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Malkowski SN, Atilho RM, Greenlee EB, Weinberg CE, Breaker RR. A rare bacterial RNA motif is implicated in the regulation of the purF gene whose encoded enzyme synthesizes phosphoribosylamine. RNA (NEW YORK, N.Y.) 2020; 26:1838-1846. [PMID: 32843366 PMCID: PMC7668255 DOI: 10.1261/rna.077313.120] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Accepted: 08/14/2020] [Indexed: 05/31/2023]
Abstract
The Fibro-purF motif is a putative structured noncoding RNA domain that was discovered previously in species of Fibrobacter by using comparative sequence analysis methods. An updated bioinformatics search yielded a total of only 30 unique-sequence representatives, exclusively found upstream of the purF gene that codes for the enzyme amidophosphoribosyltransferase. This enzyme synthesizes the compound 5-phospho-D-ribosylamine (PRA), which is the first committed step in purine biosynthesis. The consensus model for Fibro-purF motif RNAs includes a predicted three-stem junction that carries numerous conserved nucleotide positions within the regions joining the stems. This architecture appears to be of sufficient size and complexity for the formation of the ligand-binding aptamer portion of a riboswitch. In this study, we conducted biochemical analyses of a representative Fibro-purF motif RNA to confirm that the RNA generally folds according to the predicted consensus model. However, due to the instability of PRA, binding of this ligand candidate by the RNA could not be directly assessed. Genetic analyses were used to demonstrate that Fibro-purF motif RNAs regulate gene expression in accordance with predicted PRA concentrations. These findings indicate that Fibro-purF motif RNAs are genetic regulation elements that likely suppress PRA biosynthesis when sufficient levels of this purine precursor are present.
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Affiliation(s)
- Sarah N Malkowski
- Department of Chemistry, Cellular and Developmental Biology, Yale University, New Haven, Connecticut 06520-8103, USA
| | - Ruben M Atilho
- Department of Molecular Biophysics and Biochemistry, Cellular and Developmental Biology, Yale University, New Haven, Connecticut 06520-8103, USA
| | - Etienne B Greenlee
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, Connecticut 06520-8103, USA
| | - Christina E Weinberg
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, Connecticut 06520-8103, USA
| | - Ronald R Breaker
- Department of Molecular Biophysics and Biochemistry, Cellular and Developmental Biology, Yale University, New Haven, Connecticut 06520-8103, USA
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, Connecticut 06520-8103, USA
- Howard Hughes Medical Institute, Yale University, New Haven, Connecticut 06520-8103, USA
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26
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Salvail H, Balaji A, Yu D, Roth A, Breaker RR. Biochemical Validation of a Fourth Guanidine Riboswitch Class in Bacteria. Biochemistry 2020; 59:4654-4662. [PMID: 33236895 DOI: 10.1021/acs.biochem.0c00793] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
An intriguing consequence of ongoing riboswitch discovery efforts is the occasional identification of metabolic or toxicity response pathways for unusual ligands. Recently, we reported the experimental validation of three distinct bacterial riboswitch classes that regulate gene expression in response to the selective binding of a guanidinium ion. These riboswitch classes, called guanidine-I, -II, and -III, regulate numerous genes whose protein products include previously misannotated guanidine exporters and enzymes that degrade guanidine via an initial carboxylation reaction. Guanidine is now recognized as the primal substrate of many multidrug efflux pumps that are important for bacterial resistance to certain antibiotics. Guanidine carboxylase enzymes had long been annotated as urea carboxylase enzymes but are now understood to participate in guanidine degradation. Herein, we report the existence of a fourth riboswitch class for this ligand, called guanidine-IV. Members of this class use a novel aptamer to selectively bind guanidine and use an unusual expression platform arrangement that is predicted to activate gene expression when ligand is present. The wide distribution of this abundant riboswitch class, coupled with the striking diversity of other guanidine-sensing RNAs, demonstrates that many bacterial species maintain sophisticated sensory and genetic mechanisms to avoid guanidine toxicity. This finding further highlights the mystery regarding the natural source of this nitrogen-rich chemical moiety.
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Affiliation(s)
- Hubert Salvail
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, Connecticut 06520-8103, United States
| | - Aparaajita Balaji
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, Connecticut 06520-8103, United States
| | - Diane Yu
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, Connecticut 06520-8103, United States
| | - Adam Roth
- Howard Hughes Medical Institute, Yale University, New Haven, Connecticut 06520-8103, United States
| | - Ronald R Breaker
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, Connecticut 06520-8103, United States.,Howard Hughes Medical Institute, Yale University, New Haven, Connecticut 06520-8103, United States.,Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520-8103, United States
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27
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Revisiting the Relationships Between Genomic G + C Content, RNA Secondary Structures, and Optimal Growth Temperature. J Mol Evol 2020; 89:165-171. [PMID: 33216148 DOI: 10.1007/s00239-020-09974-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Accepted: 11/09/2020] [Indexed: 10/23/2022]
Abstract
Over twenty years ago Galtier and Lobry published a manuscript entitled "Relationships between Genomic G + C Content, RNA Secondary Structure, and Optimal Growth Temperature" in the Journal of Molecular Evolution that showcased the lack of a relationship between genomic G + C content and optimal growth temperature (OGT) in a set of about 200 prokaryotes. Galtier and Lobry also assessed the relationship between RNA secondary structures (rRNA stems, tRNAs) and OGT, and in this case a clear relationship emerged. Increasing structured RNA G + C content (particularly in regions that are double-stranded) correlates with increased OGT. Both of these fundamental relationships have withstood test of many additional sequences and spawned a variety of different applications that include prediction of OGT from rRNA sequence and computational ncRNA identification approaches. In this work, I present the motivation behind Galtier and Lobry's original paper and the larger questions addressed by the work, how these questions have evolved over the last two decades, and the impact of Galtier and Lobry's manuscript in fields beyond these questions.
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28
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Role of Non-coding RNAs in Fungal Pathogenesis and Antifungal Drug Responses. CURRENT CLINICAL MICROBIOLOGY REPORTS 2020. [DOI: 10.1007/s40588-020-00151-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Abstract
Purpose of Review
Non-coding RNAs (ncRNAs), including regulatory small RNAs (sRNAs) and long non-coding RNAs (lncRNAs), constitute a significant part of eukaryotic genomes; however, their roles in fungi are just starting to emerge. ncRNAs have been shown to regulate gene expression in response to varying environmental conditions (like stress) and response to chemicals, including antifungal drugs. In this review, I highlighted recent studies focusing on the functional roles of ncRNAs in pathogenic fungi.
Recent Findings
Emerging evidence suggests sRNAs (small RNAs) and lncRNAs (long non-coding RNAs) play an important role in fungal pathogenesis and antifungal drug response. Their roles include posttranscriptional gene silencing, histone modification, and chromatin remodeling. Fungal pathogens utilize RNA interference (RNAi) mechanisms to regulate pathogenesis-related genes and can also transfer sRNAs inside the host to suppress host immunity genes to increase virulence. Hosts can also transfer sRNAs to induce RNAi in fungal pathogens to reduce virulence. Additionally, sRNAs and lncRNAs also regulate gene expression in response to antifungal drugs increasing resistance (and possibly tolerance) to drugs.
Summary
Herein, I discuss what is known about ncRNAs in fungal pathogenesis and antifungal drug responses. Advancements in genomic technologies will help identify the ncRNA repertoire in fungal pathogens, and functional studies will elucidate their mechanisms. This will advance our understanding of host-fungal interactions and potentially help develop better treatment strategies.
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29
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Ritchey LE, Tack DC, Yakhnin H, Jolley EA, Assmann SM, Bevilacqua PC, Babitzke P. Structure-seq2 probing of RNA structure upon amino acid starvation reveals both known and novel RNA switches in Bacillus subtilis. RNA (NEW YORK, N.Y.) 2020; 26:1431-1447. [PMID: 32611709 PMCID: PMC7491331 DOI: 10.1261/rna.075986.120] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Accepted: 06/28/2020] [Indexed: 06/01/2023]
Abstract
RNA structure influences numerous processes in all organisms. In bacteria, these processes include transcription termination and attenuation, small RNA and protein binding, translation initiation, and mRNA stability, and can be regulated via metabolite availability and other stresses. Here we use Structure-seq2 to probe the in vivo RNA structurome of Bacillus subtilis grown in the presence and absence of amino acids. Our results reveal that amino acid starvation results in lower overall dimethyl sulfate (DMS) reactivity of the transcriptome, indicating enhanced protection owing to protein binding or RNA structure. Starvation-induced changes in DMS reactivity correlated inversely with transcript abundance changes. This correlation was particularly pronounced in genes associated with the stringent response and CodY regulons, which are involved in adaptation to nutritional stress, suggesting that RNA structure contributes to transcript abundance change in regulons involved in amino acid metabolism. Structure-seq2 accurately reported on four known amino acid-responsive riboswitches: T-box, SAM, glycine, and lysine riboswitches. Additionally, we discovered a transcription attenuation mechanism that reduces yfmG expression when amino acids are added to the growth medium. We also found that translation of a leader peptide (YfmH) encoded just upstream of yfmG regulates yfmG expression. Our results are consistent with a model in which a slow rate of yfmH translation caused by limitation of the amino acids encoded in YfmH prevents transcription termination in the yfmG leader region by favoring formation of an overlapping antiterminator structure. This novel RNA switch offers a way to simultaneously monitor the levels of multiple amino acids.
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Affiliation(s)
- Laura E Ritchey
- Department of Chemistry, Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - David C Tack
- Department of Biology, Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Helen Yakhnin
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, Pennsylvania 16802, USA
- Center for RNA Molecular Biology, Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Elizabeth A Jolley
- Department of Chemistry, Pennsylvania State University, University Park, Pennsylvania 16802, USA
- Center for RNA Molecular Biology, Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Sarah M Assmann
- Department of Biology, Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Philip C Bevilacqua
- Department of Chemistry, Pennsylvania State University, University Park, Pennsylvania 16802, USA
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, Pennsylvania 16802, USA
- Center for RNA Molecular Biology, Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Paul Babitzke
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, Pennsylvania 16802, USA
- Center for RNA Molecular Biology, Pennsylvania State University, University Park, Pennsylvania 16802, USA
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30
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Ardern Z, Neuhaus K, Scherer S. Are Antisense Proteins in Prokaryotes Functional? Front Mol Biosci 2020; 7:187. [PMID: 32923454 PMCID: PMC7457138 DOI: 10.3389/fmolb.2020.00187] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Accepted: 07/16/2020] [Indexed: 12/16/2022] Open
Abstract
Many prokaryotic RNAs are transcribed from loci outside of annotated protein coding genes. Across bacterial species hundreds of short open reading frames antisense to annotated genes show evidence of both transcription and translation, for instance in ribosome profiling data. Determining the functional fraction of these protein products awaits further research, including insights from studies of molecular interactions and detailed evolutionary analysis. There are multiple lines of evidence, however, that many of these newly discovered proteins are of use to the organism. Condition-specific phenotypes have been characterized for a few. These proteins should be added to genome annotations, and the methods for predicting them standardized. Evolutionary analysis of these typically young sequences also may provide important insights into gene evolution. This research should be prioritized for its exciting potential to uncover large numbers of novel proteins with extremely diverse potential practical uses, including applications in synthetic biology and responding to pathogens.
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Affiliation(s)
- Zachary Ardern
- Chair for Microbial Ecology, Technical University of Munich, Munich, Germany
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31
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Sherlock ME, Breaker RR. Former orphan riboswitches reveal unexplored areas of bacterial metabolism, signaling, and gene control processes. RNA (NEW YORK, N.Y.) 2020; 26:675-693. [PMID: 32165489 PMCID: PMC7266159 DOI: 10.1261/rna.074997.120] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Comparative sequence analyses have been used to discover numerous classes of structured noncoding RNAs, some of which are riboswitches that specifically recognize small-molecule or elemental ion ligands and influence expression of adjacent downstream genes. Determining the correct identity of the ligand for a riboswitch candidate typically is aided by an understanding of the genes under its regulatory control. Riboswitches whose ligands were straightforward to identify have largely been associated with well-characterized metabolic pathways, such as coenzyme or amino acid biosynthesis. Riboswitch candidates whose ligands resist identification, collectively known as orphan riboswitches, are often associated with genes coding for proteins of unknown function, or genes for various proteins with no established link to one another. The cognate ligands for 16 former orphan riboswitch motifs have been identified to date. The successful pursuit of the ligands for these classes has provided insight into areas of biology that are not yet fully explored, such as ion homeostasis, signaling networks, and other previously underappreciated biochemical or physiological processes. Herein we discuss the strategies and methods used to match ligands with orphan riboswitch classes, and overview the lessons learned to inform and motivate ongoing efforts to identify ligands for the many remaining candidates.
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Affiliation(s)
- Madeline E Sherlock
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520, USA
| | - Ronald R Breaker
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520, USA
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, Connecticut 06520, USA
- Howard Hughes Medical Institute, Yale University, New Haven, Connecticut 06520, USA
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32
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Righetti F, Materne SL, Boss J, Eichner H, Charpentier E, Loh E. Characterization of a transcriptional TPP riboswitch in the human pathogen Neisseria meningitidis. RNA Biol 2020; 17:718-730. [PMID: 32079473 PMCID: PMC7237195 DOI: 10.1080/15476286.2020.1727188] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Increasing evidence has demonstrated that regulatory RNA elements such as riboswitches (RS) play a pivotal role in the fine-tuning of bacterial gene expression. In this study, we investigated and characterized a novel transcriptional thiamine pyrophosphate (TPP) RS in the obligate human pathogen N. meningitidis MC58 (serogroup B). This RS is located in the 5´ untranslated region upstream of thiC gene, encoding a protein involved in TPP biosynthesis, an essential cofactor for all living beings. Primer extension revealed the transcriptional start site of thiC. Northern blot analysis of thiC mRNA and reporter gene studies confirmed the presence of an active TPP-sensing RS. Expression patterns of the wild-type RS and site-specific mutants showed that it is an OFF switch that controls transcription elongation of thiC mRNA. Interestingly, the regulatory mechanism of the meningococcal thiC RS resembles the Gram-positive Bacillus subtilis thiC RS rather than the Gram-negative Escherichia coli thiC RS. Therefore, the meningococcal thiC RS represents a rare example of transcriptional RS in a Gram-negative bacterium. We further observed that the RS is actively involved in modulating gene expression in response to different growth media and to supplemented bacterial and eukaryotic cell lysates as possible sources of nutrients in the nasopharynx. Our results suggest that RS-mediated gene regulation could influence meningococcal fitness, through the fine-tuning of biosynthesis and scavenging of nutrients and cofactors, such as thiamine.
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Affiliation(s)
- Francesco Righetti
- Department of Microbiology, Tumor- and Cell Biology, BioClinicum, Karolinska University Hospital, Stockholm, Sweden
| | - Solange Lise Materne
- Department of Microbiology, Tumor- and Cell Biology, BioClinicum, Karolinska University Hospital, Stockholm, Sweden
| | - John Boss
- Department of Microbiology, Tumor- and Cell Biology, BioClinicum, Karolinska University Hospital, Stockholm, Sweden
| | - Hannes Eichner
- Department of Microbiology, Tumor- and Cell Biology, BioClinicum, Karolinska University Hospital, Stockholm, Sweden
| | - Emmanuelle Charpentier
- Max Planck Unit for the Science of Pathogens, Berlin, Germany.,Department of Regulation in Infection Biology, Max Planck Institute for Infection Biology, Berlin, Germany.,Institute for Biology, Humboldt University, Berlin, Germany.,Department of Regulation in Infection Biology, Helmholtz Centre for Infection Research, Braunschweig, Germany.,The Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå Centre for Microbial Research (UCMR), Department of Molecular Biology, Umeå University, Umeå, Sweden
| | - Edmund Loh
- Department of Microbiology, Tumor- and Cell Biology, BioClinicum, Karolinska University Hospital, Stockholm, Sweden.,SCELSE, Nanyang Technological University, Singapore, Singapore
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33
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Atilho RM, Mirihana Arachchilage G, Greenlee EB, Knecht KM, Breaker RR. A bacterial riboswitch class for the thiamin precursor HMP-PP employs a terminator-embedded aptamer. eLife 2019; 8:45210. [PMID: 30950790 PMCID: PMC6478431 DOI: 10.7554/elife.45210] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Accepted: 04/04/2019] [Indexed: 12/29/2022] Open
Abstract
We recently implemented a bioinformatics pipeline that can uncover novel, but rare, riboswitch candidates as well as other noncoding RNA structures in bacteria. A prominent candidate revealed by our initial search efforts was called the ‘thiS motif’ because of its frequent association with a gene coding for the ThiS protein, which delivers sulfur to form the thiazole moiety of the thiamin precursor HET-P. In the current report, we describe biochemical and genetic data demonstrating that thiS motif RNAs function as sensors of the thiamin precursor HMP-PP, which is fused with HET-P ultimately to form the final active coenzyme thiamin pyrophosphate (TPP). HMP-PP riboswitches exhibit a distinctive architecture wherein an unusually small ligand-sensing aptamer is almost entirely embedded within an otherwise classic intrinsic transcription terminator stem. This arrangement yields remarkably compact genetic switches that bacteria use to tune the levels of thiamin precursors during the biosynthesis of this universally distributed coenzyme. Many bacteria use small genetic devices called riboswitches to sense molecules that are essential for life and regulate the genes necessary to make, break or move these molecules. Riboswitches are made of molecules of RNA and appear to have ancient origins that predate the evolution of bacteria and other lifeforms made of cells. Inside modern bacteria, chunks of DNA in the genome provide the instructions to make riboswitches and around 40 different types of riboswitch have been identified so far. However, it has been proposed that the instructions for thousands more riboswitches may remain hidden in the DNA of bacteria. All of the currently known riboswitches contain a region called an aptamer that binds to a target molecule. This binding causes another structure in the riboswitch RNA to switch a specific gene on or off. For example, the aptamer binding might cause a hairpin-like structure called a terminator to form, which stops a gene being used to make new RNA molecules. In 2019 a team of researchers reported using a computational approach to identify new riboswitches in bacteria. This approach identified many different chunks of DNA that might code for a riboswitch, including one known as the thiS motif. This potential new riboswitch appeared to be associated with a gene that encodes a protein required to make a vitamin called thiamin (also known as vitamin B1). To test the new computational approach, Atilho et al. including several of the researchers involved in the earlier work used genetic and biochemical techniques to study the thiS motif. The experiments revealed that the motif binds to a molecule called HMP-PP, which bacteria use to make thiamin. Unexpectedly, the aptamer of the riboswitch was nested within a terminator, rather than being a separate entity. The findings of Atilho et al. reveal that riboswitches can be even more compact than previously thought. Furthermore, these findings reveal new insights into how bacteria use riboswitches to manage their vitamin levels. In the future it may be possible to develop drugs that target such riboswitches to starve bacteria of these essential molecules.
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Affiliation(s)
- Ruben M Atilho
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, United States
| | | | - Etienne B Greenlee
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, United States
| | - Kirsten M Knecht
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, United States
| | - Ronald R Breaker
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, United States.,Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, United States
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