1
|
Fernando CM, Breaker RR. Bioinformatic prediction of proteins relevant to functions of the bacterial OLE ribonucleoprotein complex. mSphere 2024:e0015924. [PMID: 38771028 DOI: 10.1128/msphere.00159-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2024] [Accepted: 04/19/2024] [Indexed: 05/22/2024] Open
Abstract
OLE (ornate, large, extremophilic) RNAs are members of a noncoding RNA class present in many Gram-positive, extremophilic bacteria. The large size, complex structure, and extensive sequence conservation of OLE RNAs are characteristics consistent with the hypothesis that they likely function as ribozymes. The OLE RNA representative from Halalkalibacterium halodurans is known to localize to the phospholipid membrane and requires at least three essential protein partners: OapA, OapB, and OapC. However, the precise biochemical functions of this unusual ribonucleoprotein (RNP) complex remain unknown. Genetic disruption of OLE RNA or its partners revealed that the complex is beneficial under diverse stress conditions. To search for additional links between OLE RNA and other cellular components, we used phylogenetic profiling to identify proteins that are either correlated or anticorrelated with the presence of OLE RNA in various bacterial species. This analysis revealed strong correlations between the essential protein-binding partners of OLE RNA and organisms that carry the ole gene. Similarly, proteins involved in sporulation are correlated, suggesting a potential role for the OLE RNP complex in spore formation. Intriguingly, the Mg2+ transporter MpfA is strongly anticorrelated with OLE RNA. Evidence indicates that MpfA is structurally related to OapA and therefore MpfA may serve as a functional replacement for some contributions otherwise performed by the OLE RNP complex in species that lack this device. Indeed, OLE RNAs might represent an ancient RNA class that enabled primitive organisms to sense and respond to major cellular stresses.IMPORTANCEOLE (ornate, large, extremophilic) RNAs were first reported nearly 20 years ago, and they represent one of the largest and most intricately folded noncoding RNA classes whose biochemical function remains to be established. Other RNAs with similar size, structural complexity, and extent of sequence conservation have proven to catalyze chemical transformations. Therefore, we speculate that OLE RNAs likewise operate as ribozymes and that they might catalyze a fundamental reaction that has persisted since the RNA World era-a time before the emergence of proteins in evolution. To seek additional clues regarding the function of OLE RNA, we undertook a computational effort to identify potential protein components of the OLE ribonucleoprotein (RNP) complex or other proteins that have functional links to this device. This analysis revealed known protein partners and several additional proteins that might be physically or functionally linked to the OLE RNP complex. Finally, we identified a Mg2+ transporter protein, MpfA, that strongly anticorrelates with the OLE RNP complex. This latter result suggests that MpfA might perform at least some functions that are like those carried out by the OLE RNP complex.
Collapse
Affiliation(s)
- Chrishan M Fernando
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, USA
| | - Ronald R Breaker
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, USA
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, Connecticut, USA
- Howard Hughes Medical Institute, Yale University, New Haven, Connecticut, USA
| |
Collapse
|
2
|
Liu T, Pyle AM. Highly Reactive Group I Introns Ubiquitous in Pathogenic Fungi. J Mol Biol 2024; 436:168513. [PMID: 38447889 DOI: 10.1016/j.jmb.2024.168513] [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: 01/02/2024] [Revised: 02/25/2024] [Accepted: 02/27/2024] [Indexed: 03/08/2024]
Abstract
Systemic fungal infections are a growing public health threat, and yet viable antifungal drug targets are limited as fungi share a similar proteome with humans. However, features of RNA metabolism and the noncoding transcriptomes in fungi are distinctive. For example, fungi harbor highly structured RNA elements that humans lack, such as self-splicing introns within key housekeeping genes in the mitochondria. However, the location and function of these mitochondrial riboregulatory elements has largely eluded characterization. Here we used an RNA-structure-based bioinformatics pipeline to identify the group I introns interrupting key mitochondrial genes in medically relevant fungi, revealing their fixation within a handful of genetic hotspots and their ubiquitous presence across divergent phylogenies of fungi, including all highest priority pathogens such as Candida albicans, Candida auris, Aspergillus fumigatus and Cryptococcus neoformans. We then biochemically characterized two representative introns from C. albicans and C. auris, demonstrating their exceptionally efficient splicing catalysis relative to previously-characterized group I introns. Indeed, the C. albicans mitochondrial intron displays extremely rapid catalytic turnover, even at ambient temperatures and physiological magnesium ion concentrations. Our results unmask a significant new set of players in the RNA metabolism of pathogenic fungi, suggesting a promising new type of antifungal drug target.
Collapse
Affiliation(s)
- Tianshuo Liu
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06520, USA
| | - Anna Marie Pyle
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06520, USA; Department of Chemistry, Yale University, New Haven, CT 06520, USA; Howard Hughes Medical Institute, Yale University, New Haven, CT 06520, USA.
| |
Collapse
|
3
|
Gomes RMODS, Silva KJGD, Theodoro RC. Group I introns: Structure, splicing and their applications in medical mycology. Genet Mol Biol 2024; 47Suppl 1:e20230228. [PMID: 38525907 DOI: 10.1590/1678-4685-gmb-2023-0228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Accepted: 02/02/2024] [Indexed: 03/26/2024] Open
Abstract
Group I introns are small RNAs (250-500 nt) capable of catalyzing their own splicing from the precursor RNA. They are widely distributed across the tree of life and have intricate relationships with their host genomes. In this work, we review its basic structure, self-splicing and its mechanisms of gene mobility. As they are widely found in unicellular eukaryotes, especially fungi, we gathered information regarding their possible impact on the physiology of fungal cells and the possible application of these introns in medical mycology.
Collapse
Affiliation(s)
| | | | - Raquel Cordeiro Theodoro
- Universidade Federal do Rio Grande do Norte, Instituto de Medicina Tropical do Rio Grande do Norte, Natal, RN, Brazil
- Universidade Federal do Rio Grande do Norte, Centro de Biociências, Departamento de Biologia Celular de Genética, Natal, RN, Brazil
| |
Collapse
|
4
|
Putzeys L, Wicke L, Boon M, van Noort V, Vogel J, Lavigne R. Refining the transcriptional landscapes for distinct clades of virulent phages infecting Pseudomonas aeruginosa. MICROLIFE 2024; 5:uqae002. [PMID: 38444699 PMCID: PMC10914365 DOI: 10.1093/femsml/uqae002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Revised: 01/24/2024] [Accepted: 02/27/2024] [Indexed: 03/07/2024]
Abstract
The introduction of high-throughput sequencing has resulted in a surge of available bacteriophage genomes, unveiling their tremendous genomic diversity. However, our current understanding of the complex transcriptional mechanisms that dictate their gene expression during infection is limited to a handful of model phages. Here, we applied ONT-cappable-seq to reveal the transcriptional architecture of six different clades of virulent phages infecting Pseudomonas aeruginosa. This long-read microbial transcriptomics approach is tailored to globally map transcription start and termination sites, transcription units, and putative RNA-based regulators on dense phage genomes. Specifically, the full-length transcriptomes of LUZ19, LUZ24, 14-1, YuA, PAK_P3, and giant phage phiKZ during early, middle, and late infection were collectively charted. Beyond pinpointing traditional promoter and terminator elements and transcription units, these transcriptional profiles provide insights in transcriptional attenuation and splicing events and allow straightforward validation of Group I intron activity. In addition, ONT-cappable-seq data can guide genome-wide discovery of novel regulatory element candidates, including noncoding RNAs and riboswitches. This work substantially expands the number of annotated phage-encoded transcriptional elements identified to date, shedding light on the intricate and diverse gene expression regulation mechanisms in Pseudomonas phages, which can ultimately be sourced as tools for biotechnological applications in phage and bacterial engineering.
Collapse
Affiliation(s)
- Leena Putzeys
- Department of Biosystems, Laboratory of Gene Technology, KU Leuven, Kasteelpark Arenberg 21, 3001 Leuven, Belgium
| | - Laura Wicke
- Department of Biosystems, Laboratory of Gene Technology, KU Leuven, Kasteelpark Arenberg 21, 3001 Leuven, Belgium
- Institute for Molecular Infection Biology (IMIB), Medical Faculty, University of Würzburg, Josef-Schneider-Straße 2, 97080 Würzburg, Germany
| | - Maarten Boon
- Department of Biosystems, Laboratory of Gene Technology, KU Leuven, Kasteelpark Arenberg 21, 3001 Leuven, Belgium
| | - Vera van Noort
- Centre of Microbial and Plant Genetics, KU Leuven, Kasteelpark Arenberg 20, 3001 Leuven, Belgium
- Institute of Biology, Leiden University, Sylviusweg 72, 2333 BE Leiden, the Netherlands
| | - Jörg Vogel
- Institute for Molecular Infection Biology (IMIB), Medical Faculty, University of Würzburg, Josef-Schneider-Straße 2, 97080 Würzburg, Germany
- Helmholtz Institute for RNA-Based Infection Research (HIRI), Helmholtz Centre for Infection Research (HZI), Josef-Schneider-Straße 2, 97080 Würzburg, Germany
| | - Rob Lavigne
- Department of Biosystems, Laboratory of Gene Technology, KU Leuven, Kasteelpark Arenberg 21, 3001 Leuven, Belgium
| |
Collapse
|
5
|
Soares LW, King CG, Fernando CM, Roth A, Breaker RR. Genetic disruption of the bacterial raiA motif noncoding RNA causes defects in sporulation and aggregation. Proc Natl Acad Sci U S A 2024; 121:e2318008121. [PMID: 38306478 PMCID: PMC10861870 DOI: 10.1073/pnas.2318008121] [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: 10/16/2023] [Accepted: 12/02/2023] [Indexed: 02/04/2024] Open
Abstract
Several structured noncoding RNAs in bacteria are essential contributors to fundamental cellular processes. Thus, discoveries of additional ncRNA classes provide opportunities to uncover and explore biochemical mechanisms relevant to other major and potentially ancient processes. A candidate structured ncRNA named the "raiA motif" has been found via bioinformatic analyses in over 2,500 bacterial species. The gene coding for the RNA typically resides between the raiA and comFC genes of many species of Bacillota and Actinomycetota. Structural probing of the raiA motif RNA from the Gram-positive anaerobe Clostridium acetobutylicum confirms key features of its sophisticated secondary structure model. Expression analysis of raiA motif RNA reveals that the RNA is constitutively produced but reaches peak abundance during the transition from exponential growth to stationary phase. The raiA motif RNA becomes the fourth most abundant RNA in C. acetobutylicum, excluding ribosomal RNAs and transfer RNAs. Genetic disruption of the raiA motif RNA causes cells to exhibit substantially decreased spore formation and diminished ability to aggregate. Restoration of normal cellular function in this knock-out strain is achieved by expression of a raiA motif gene from a plasmid. These results demonstrate that raiA motif RNAs normally participate in major cell differentiation processes by operating as a trans-acting factor.
Collapse
Affiliation(s)
- Lucas W. Soares
- Department of Microbial Pathogenesis, Yale University, New Haven, CT06536
| | - Christopher G. King
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT06511-8103
| | - Chrishan M. Fernando
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT06511-8103
| | - Adam Roth
- HHMI, Yale University, New Haven, CT06511-8103
| | - Ronald R. Breaker
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT06511-8103
- HHMI, Yale University, New Haven, CT06511-8103
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT06511-8103
| |
Collapse
|
6
|
Jeong DE, Sundrani S, Hall RN, Krupovic M, Koonin EV, Fire AZ. DNA Polymerase Diversity Reveals Multiple Incursions of Polintons During Nematode Evolution. Mol Biol Evol 2023; 40:msad274. [PMID: 38069639 DOI: 10.1093/molbev/msad274] [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: 08/24/2023] [Revised: 11/01/2023] [Accepted: 12/04/2023] [Indexed: 12/19/2023] Open
Abstract
Polintons are double-stranded DNA, virus-like self-synthesizing transposons widely found in eukaryotic genomes. Recent metagenomic discoveries of Polinton-like viruses are consistent with the hypothesis that Polintons invade eukaryotic host genomes through infectious viral particles. Nematode genomes contain multiple copies of Polintons and provide an opportunity to explore the natural distribution and evolution of Polintons during this process. We performed an extensive search of Polintons across nematode genomes, identifying multiple full-length Polinton copies in several species. We provide evidence of both ancient Polinton integrations and recent mobility in strains of the same nematode species. In addition to the major nematode Polinton family, we identified a group of Polintons that are overall closely related to the major family but encode a distinct protein-primed DNA polymerase B (pPolB) that is related to homologs from a different group of Polintons present outside of the Nematoda. Phylogenetic analyses on the pPolBs support the evolutionary scenarios in which these extrinsic pPolBs that seem to derive from Polinton families present in oomycetes and molluscs replaced the canonical pPolB in subsets of Polintons found in terrestrial and marine nematodes, respectively, suggesting interphylum horizontal gene transfers. The pPolBs of the terrestrial nematode and oomycete Polintons share a unique feature, an insertion of an HNH nuclease domain, whereas the pPolBs in the marine nematode Polintons share an insertion of a VSR nuclease domain with marine mollusc pPolBs. We hypothesize that horizontal gene transfer occurs among Polintons from widely different but cohabiting hosts.
Collapse
Affiliation(s)
- Dae-Eun Jeong
- Department of Pathology, Stanford University School of Medicine, Stanford, CA, USA
| | - Sameer Sundrani
- Department of Bioengineering, Stanford University, Stanford, CA, USA
- Present address: Department of Biomedical Informatics, Vanderbilt University School of Medicine, Nashville, TN, USA
| | | | - Mart Krupovic
- Institut Pasteur, Université Paris Cité, Archaeal Virology Unit, Paris, France
| | - Eugene V Koonin
- National National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD, USA
| | - Andrew Z Fire
- Department of Pathology, Stanford University School of Medicine, Stanford, CA, USA
- Department of Genetics, Stanford University School of Medicine, Stanford, CA, USA
| |
Collapse
|
7
|
Žedaveinytė R, Meers C, Le HC, Mortman EE, Tang S, Lampe GD, Pesari SR, Gelsinger DR, Wiegand T, Sternberg SH. Antagonistic conflict between transposon-encoded introns and guide RNAs. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.20.567912. [PMID: 38045383 PMCID: PMC10690162 DOI: 10.1101/2023.11.20.567912] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/05/2023]
Abstract
TnpB nucleases represent the evolutionary precursors to CRISPR-Cas12 and are widespread in all domains of life, presumably due to the critical roles they play in transposon proliferation. IS605family TnpB homologs function in bacteria as programmable homing endonucleases by exploiting transposon-encoded guide RNAs to cleave vacant genomic sites, thereby driving transposon maintenance through DSB-stimulated homologous recombination. Whether this pathway is conserved in other genetic contexts, and in association with other transposases, is unknown. Here we uncover molecular mechanisms of transposition and RNA-guided DNA cleavage by IS607-family elements that, remarkably, also encode catalytic, self-splicing group I introns. After reconstituting and systematically investigating each of these biochemical activities for a candidate 'IStron' derived from Clostridium botulinum, we discovered sequence and structural features of the transposon-encoded RNA that satisfy molecular requirements of a group I intron and TnpB guide RNA, while still retaining the ability to be faithfully mobilized at the DNA level by the TnpA transposase. Strikingly, intron splicing was strongly repressed not only by TnpB, but also by the secondary structure of ωRNA alone, allowing the element to carefully control the relative levels of spliced products versus functional guide RNAs. Our results suggest that IStron transcripts have evolved a sensitive equilibrium to balance competing and mutually exclusive activities that promote transposon maintenance while limiting adverse fitness costs on the host. Collectively, this work explains how diverse enzymatic activities emerged during the selfish spread of IS607-family elements and highlights molecular innovation in the multi-functional utility of transposon-encoded noncoding RNAs.
Collapse
Affiliation(s)
- Rimantė Žedaveinytė
- Department of Biochemistry and Molecular Biophysics, Columbia University; New York, NY 10032, USA
| | - Chance Meers
- Department of Biochemistry and Molecular Biophysics, Columbia University; New York, NY 10032, USA
| | - Hoang C. Le
- Department of Biochemistry and Molecular Biophysics, Columbia University; New York, NY 10032, USA
| | - Edan E. Mortman
- Department of Genetics and Development, Columbia University; New York, NY 10032, USA
| | - Stephen Tang
- Department of Biochemistry and Molecular Biophysics, Columbia University; New York, NY 10032, USA
| | - George D. Lampe
- Department of Biochemistry and Molecular Biophysics, Columbia University; New York, NY 10032, USA
| | - Sanjana R. Pesari
- Department of Biochemistry and Molecular Biophysics, Columbia University; New York, NY 10032, USA
- Present address: Biochemistry and Molecular Biophysics Program, University of California, San Diego, CA, USA
| | - Diego R. Gelsinger
- Department of Biochemistry and Molecular Biophysics, Columbia University; New York, NY 10032, USA
| | - Tanner Wiegand
- Department of Biochemistry and Molecular Biophysics, Columbia University; New York, NY 10032, USA
| | - Samuel H. Sternberg
- Department of Biochemistry and Molecular Biophysics, Columbia University; New York, NY 10032, USA
| |
Collapse
|
8
|
He TT, Xu YF, Li X, Wang X, Li JY, Ou-Yang D, Cheng HS, Li HY, Qin J, Huang Y, Wang HY. A linear and circular dual-conformation noncoding RNA involved in oxidative stress tolerance in Bacillus altitudinis. Nat Commun 2023; 14:5722. [PMID: 37714854 PMCID: PMC10504365 DOI: 10.1038/s41467-023-41491-4] [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: 03/07/2023] [Accepted: 09/06/2023] [Indexed: 09/17/2023] Open
Abstract
Circular RNAs have been extensively studied in eukaryotes, but their presence and/or biological functionality in bacteria are unclear. Here, we show that a regulatory noncoding RNA (DucS) exists in both linear and circular conformation in Bacillus altitudinis. The linear forms promote B. altitudinis tolerance to H2O2 stress, partly through increased translation of a stress-responsive gene, htrA. The 3' end sequences of the linear forms are crucial for RNA circularization, and formation of circular forms can decrease the levels of the regulatory linear cognates. Bioinformatic analysis of available RNA-seq datasets from 30 bacterial species revealed multiple circular RNA candidates, distinct from DucS, for all the examined species. Experiments testing for the presence of selected circular RNA candidates in four species successfully validated 7 out of 9 candidates from B. altitudinis and 4 out of 5 candidates from Bacillus paralicheniformis; However, none of the candidates tested for Bacillus subtilis and Escherichia coli were detected. Our work identifies a dual-conformation regulatory RNA in B. altitutidinis, and indicates that circular RNAs exist in diverse bacteria. However, circularization of specific RNAs does not seem to be conserved across species, and the circularization mechanisms and biological functionality of the circular forms remain unclear.
Collapse
Affiliation(s)
- Ting-Ting He
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, Sichuan, China
- Department of Thoracic Surgery, West China Hospital, Sichuan University, Chengdu, China
| | - Yun-Fan Xu
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, Sichuan, China
| | - Xiang Li
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, Sichuan, China
| | - Xia Wang
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, Sichuan, China
| | - Jie-Yu Li
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, Sichuan, China
| | - Dan Ou-Yang
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, Sichuan, China
| | - Han-Sen Cheng
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, Sichuan, China
| | - Hao-Yang Li
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, Sichuan, China
| | - Jia Qin
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, Sichuan, China
| | - Yu Huang
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, Sichuan, China
| | - Hai-Yan Wang
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, Sichuan, China.
| |
Collapse
|
9
|
Jeong DE, Sundrani S, Hall RN, Krupovic M, Koonin EV, Fire AZ. DNA polymerase diversity reveals multiple incursions of Polintons during nematode evolution. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.22.554363. [PMID: 37662302 PMCID: PMC10473752 DOI: 10.1101/2023.08.22.554363] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/05/2023]
Abstract
Polintons are dsDNA, virus-like self-synthesizing transposons widely found in eukaryotic genomes. Recent metagenomic discoveries of Polinton-like viruses are consistent with the hypothesis that Polintons invade eukaryotic host genomes through infectious viral particles. Nematode genomes contain multiple copies of Polintons and provide an opportunity to explore the natural distribution and evolution of Polintons during this process. We performed an extensive search of Polintons across nematode genomes, identifying multiple full-length Polinton copies in several species. We provide evidence of both ancient Polinton integrations and recent mobility in strains of the same nematode species. In addition to the major nematode Polinton family, we identified a group of Polintons that are overall closely related to the major family, but encode a distinct protein-primed B family DNA polymerase (pPolB) that is related to homologs from a different group of Polintons present outside of the Nematoda . Phylogenetic analyses on the pPolBs support the evolutionary scenarios in which these extrinsic pPolBs that seem to derive from Polinton families present in oomycetes and molluscs replaced the canonical pPolB in subsets of Polintons found in terrestrial and marine nematodes, respectively, suggesting inter-phylum horizontal gene transfers. The pPolBs of the terrestrial nematode and oomycete Polintons share a unique feature, an insertion of a HNH nuclease domain, whereas the pPolBs in the marine nematode Polintons share an insertion of a VSR nuclease domain with marine mollusc pPolBs. We hypothesize that horizontal gene transfer occurs among Polintons from widely different but cohabiting hosts.
Collapse
|
10
|
Malbert B, Labaurie V, Dorme C, Paget E. Group I Intron as a Potential Target for Antifungal Compounds: Development of a Trans-Splicing High-Throughput Screening Strategy. Molecules 2023; 28:molecules28114460. [PMID: 37298936 DOI: 10.3390/molecules28114460] [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: 05/02/2023] [Revised: 05/23/2023] [Accepted: 05/24/2023] [Indexed: 06/12/2023] Open
Abstract
The search for safe and efficient new antifungal compounds for agriculture has led to more efforts in finding new modes of action. This involves the discovery of new molecular targets, including coding and non-coding RNA. Rarely found in plants and animals but present in fungi, group I introns are of interest as their complex tertiary structure may allow selective targeting using small molecules. In this work, we demonstrate that group I introns present in phytopathogenic fungi have a self-splicing activity in vitro that can be adapted in a high-throughput screening to find new antifungal compounds. Ten candidate introns from different filamentous fungi were tested and one group ID intron found in F. oxysporum showed high self-splicing efficiency in vitro. We designed the Fusarium intron to act as a trans-acting ribozyme and used a fluorescence-based reporter system to monitor its real time splicing activity. Together, these results are opening the way to study the druggability of such introns in crop pathogen and potentially discover small molecules selectively targeting group I introns in future high-throughput screenings.
Collapse
Affiliation(s)
- Bastien Malbert
- Early Discovery, Biochemistry Excellence, Centre de Recherche La Dargoire, Bayer SAS, 69009 Lyon, France
| | - Virginie Labaurie
- Early Discovery, Biochemistry Excellence, Centre de Recherche La Dargoire, Bayer SAS, 69009 Lyon, France
| | - Cécile Dorme
- Early Discovery, Biochemistry Excellence, Centre de Recherche La Dargoire, Bayer SAS, 69009 Lyon, France
| | - Eric Paget
- Early Discovery, Biochemistry Excellence, Centre de Recherche La Dargoire, Bayer SAS, 69009 Lyon, France
| |
Collapse
|
11
|
Himmelstrand K, Brandström Durling M, Karlsson M, Stenlid J, Olson Å. Multiple rearrangements and low inter- and intra-species mitogenome sequence variation in the Heterobasidion annosum s.l. species complex. Front Microbiol 2023; 14:1159811. [PMID: 37275157 PMCID: PMC10234125 DOI: 10.3389/fmicb.2023.1159811] [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: 02/06/2023] [Accepted: 03/16/2023] [Indexed: 06/07/2023] Open
Abstract
Introduction Mitochondria are essential organelles in the eukaryotic cells and responsible for the energy production but are also involved in many other functions including virulence of some fungal species. Although the evolution of fungal mitogenomes have been studied at some taxonomic levels there are still many things to be learned from studies of closely related species. Methods In this study, we have analyzed 60 mitogenomes in the five species of the Heterobasidion annosum sensu lato complex that all are necrotrophic pathogens on conifers. Results and Discussion Compared to other fungal genera the genomic and genetic variation between and within species in the complex was low except for multiple rearrangements. Several translocations of large blocks with core genes have occurred between the five species and rearrangements were frequent in intergenic areas. Mitogenome lengths ranged between 108 878 to 116 176 bp, mostly as a result of intron variation. There was a high degree of homology of introns, homing endonuclease genes, and intergenic ORFs among the five Heterobasidion species. Three intergenic ORFs with unknown function (uORF6, uORF8 and uORF9) were found in all five species and was located in conserved synteny blocks. A 13 bp long GC-containing self-complementary palindrome was discovered in many places in the five species that were optional in presence/absence. The within species variation is very low, among 48 H. parviporum mitogenomes, there was only one single intron exchange, and SNP frequency was 0.28% and indel frequency 0.043%. The overall low variation in the Heterobasidion annosum sensu lato complex suggests a slow evolution of the mitogenome.
Collapse
|
12
|
Pavlinova P, Lambert CN, Malaterre C, Nghe P. Abiogenesis through gradual evolution of autocatalysis into template-based replication. FEBS Lett 2023; 597:344-379. [PMID: 36203246 DOI: 10.1002/1873-3468.14507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Revised: 09/20/2022] [Accepted: 09/29/2022] [Indexed: 11/11/2022]
Abstract
How life emerged from inanimate matter is one of the most intriguing questions posed to modern science. Central to this research are experimental attempts to build systems capable of Darwinian evolution. RNA catalysts (ribozymes) are a promising avenue, in line with the RNA world hypothesis whereby RNA pre-dated DNA and proteins. Since evolution in living organisms relies on template-based replication, the identification of a ribozyme capable of replicating itself (an RNA self-replicase) has been a major objective. However, no self-replicase has been identified to date. Alternatively, autocatalytic systems involving multiple RNA species capable of ligation and recombination may enable self-reproduction. However, it remains unclear how evolution could emerge in autocatalytic systems. In this review, we examine how experimentally feasible RNA reactions catalysed by ribozymes could implement the evolutionary properties of variation, heredity and reproduction, and ultimately allow for Darwinian evolution. We propose a gradual path for the emergence of evolution, initially supported by autocatalytic systems leading to the later appearance of RNA replicases.
Collapse
Affiliation(s)
- Polina Pavlinova
- Laboratoire de Biophysique et Evolution, UMR CNRS-ESPCI 8231 Chimie Biologie Innovation, PSL University, Paris, France
| | - Camille N Lambert
- Laboratoire de Biophysique et Evolution, UMR CNRS-ESPCI 8231 Chimie Biologie Innovation, PSL University, Paris, France
| | - Christophe Malaterre
- Laboratory of Philosophy of Science (LAPS) and Centre Interuniversitaire de Recherche sur la Science et la Technologie (CIRST), Université du Québec à Montréal (UQAM), Canada
| | - Philippe Nghe
- Laboratoire de Biophysique et Evolution, UMR CNRS-ESPCI 8231 Chimie Biologie Innovation, PSL University, Paris, France
| |
Collapse
|
13
|
Mohanta TK, Mohanta YK, Sharma N. Anticodon table of the chloroplast genome and identification of putative quadruplet anticodons in chloroplast tRNAs. Sci Rep 2023; 13:760. [PMID: 36641535 PMCID: PMC9840617 DOI: 10.1038/s41598-023-27886-9] [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: 07/01/2022] [Accepted: 01/10/2023] [Indexed: 01/16/2023] Open
Abstract
The chloroplast genome of 5959 species was analyzed to construct the anticodon table of the chloroplast genome. Analysis of the chloroplast transfer ribonucleic acid (tRNA) revealed the presence of a putative quadruplet anticodon containing tRNAs in the chloroplast genome. The tRNAs with putative quadruplet anticodons were UAUG, UGGG, AUAA, GCUA, and GUUA, where the GUUA anticodon putatively encoded tRNAAsn. The study also revealed the complete absence of tRNA genes containing ACU, CUG, GCG, CUC, CCC, and CGG anticodons in the chloroplast genome from the species studied so far. The chloroplast genome was also found to encode tRNAs encoding N-formylmethionine (fMet), Ile2, selenocysteine, and pyrrolysine. The chloroplast genomes of mycoparasitic and heterotrophic plants have had heavy losses of tRNA genes. Furthermore, the chloroplast genome was also found to encode putative spacer tRNA, tRNA fragments (tRFs), tRNA-derived, stress-induced RNA (tiRNAs), and the group I introns. An evolutionary analysis revealed that chloroplast tRNAs had evolved via multiple common ancestors and the GC% had more influence toward encoding the tRNA number in the chloroplast genome than the genome size.
Collapse
Affiliation(s)
- Tapan Kumar Mohanta
- Natural and Medical Sciences Research Center, University of Nizwa, 616, Nizwa, Oman.
| | - Yugal Kishore Mohanta
- Department of Applied Biology, School of Biological Sciences, University of Science and Technology Meghalaya, Baridua, Meghalaya, 793101, India
| | - Nanaocha Sharma
- Institute of Bioresources and Sustainable Development, Imphal, Manipur, 795001, India.
| |
Collapse
|
14
|
Heterologous expression of hAID in E. coli leads to the production of a splice isoform of AID: hAIDδC, a mystery to be explored. Protein Expr Purif 2022; 199:106149. [PMID: 35952962 DOI: 10.1016/j.pep.2022.106149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 07/20/2022] [Accepted: 07/25/2022] [Indexed: 11/21/2022]
Abstract
Activation-induced cytidine deaminase (AID) is a key player that initiates antibody diversification in activated B-cell. AID mediates somatic hypermutation (SHM) and class switch recombination (CSR) via the deamination of cytosine to uracil at the Ig locus, resulting in the production of high-affinity antibodies. AID is predominantly restricted to Ig genes, whereas off-targeting of AID leads to lymphocyte-related malignancies. Interestingly, apart from FL-AID other splice isoforms of AID are highly expressed in the lymphocyte malignancies. In our study, we found that the heterologous expression of hAID-FL in E. coli cells produced two induced bands of hAID as demonstrated by SDS-PAGE and western blotting. Remarkably, peptide mapping data predicted that one band is hAID-FL and the other is its splice isoform, hAIDδE4a. To get an insight into why E. coli cells expressed hAID-FL and hAID variant, we mutated the 5' and 3' splice site of a putative intron of hAID, but it failed to produce only hAID-FL. Incidentally, hAID expressed with fusion partners also displayed two bands, and peptide mapping data strongly suggest that besides hAID-FL, the lower band showed a significant number of amino acids missing towards the C-terminal domain (named as hAIDδC). Our results are the first report to show that expression of recombinant hAID alone or irrespective of solubilization tags in E. coli cells produced hAID-FL and hAIDδC. It will be fascinating to explore the potential mechanism underlying the expression of hAIDδC from recombinant hAID plasmid in E. coli cells.
Collapse
|
15
|
Erdrich SH, Sharma V, Schurr U, Arsova B, Frunzke J. Isolation of Novel Xanthomonas Phages Infecting the Plant Pathogens X. translucens and X. campestris. Viruses 2022; 14:v14071449. [PMID: 35891434 PMCID: PMC9316219 DOI: 10.3390/v14071449] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Revised: 06/22/2022] [Accepted: 06/28/2022] [Indexed: 12/18/2022] Open
Abstract
The genus of Xanthomonas contains many well-known plant pathogens with the ability to infect some of the most important crop plants, thereby causing significant economic damage. Unfortunately, classical pest-control strategies are neither particularly efficient nor sustainable and we are, therefore, in demand of alternatives. Here, we present the isolation and characterization of seven novel phages infecting the plant-pathogenic species Xanthomonas translucens and Xanthomonas campestris. Transmission electron microscopy revealed that all phages show a siphovirion morphology. The analysis of genome sequences and plaque morphologies are in agreement with a lytic lifestyle of the phages making them suitable candidates for biocontrol. Moreover, three of the isolated phages form the new genus “Shirevirus”. All seven phages belong to four distinct clusters underpinning their phylogenetic diversity. Altogether, this study presents the first characterized isolates for the plant pathogen X. translucens and expands the number of available phages for plant biocontrol.
Collapse
Affiliation(s)
- Sebastian H. Erdrich
- Institute of Bio- and Geosciences, Department for Plant Sciences (IBG-2), Forschungszentrum Jülich, 52425 Jülich, Germany; (S.H.E.); (U.S.); (B.A.)
| | - Vikas Sharma
- Institute of Bio- and Geosciences, Department for Biotechnology (IBG-1), Forschungszentrum Jülich, 52425 Jülich, Germany;
| | - Ulrich Schurr
- Institute of Bio- and Geosciences, Department for Plant Sciences (IBG-2), Forschungszentrum Jülich, 52425 Jülich, Germany; (S.H.E.); (U.S.); (B.A.)
| | - Borjana Arsova
- Institute of Bio- and Geosciences, Department for Plant Sciences (IBG-2), Forschungszentrum Jülich, 52425 Jülich, Germany; (S.H.E.); (U.S.); (B.A.)
| | - Julia Frunzke
- Institute of Bio- and Geosciences, Department for Biotechnology (IBG-1), Forschungszentrum Jülich, 52425 Jülich, Germany;
- Correspondence: ; Tel.: +49-2461-615430
| |
Collapse
|
16
|
Unprecedented frequency of mitochondrial introns in colonial bilaterians. Sci Rep 2022; 12:10889. [PMID: 35764672 PMCID: PMC9240083 DOI: 10.1038/s41598-022-14477-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Accepted: 06/07/2022] [Indexed: 11/16/2022] Open
Abstract
Animal mitogenomes are typically devoid of introns. Here, we report the largest number of mitochondrial introns ever recorded from bilaterian animals. Mitochondrial introns were identified for the first time from the phylum Bryozoa. They were found in four species from three families (Order Cheilostomatida). A total of eight introns were found in the complete mitogenome of Exechonella vieirai, and five, 17 and 18 introns were found in the partial mitogenomes of Parantropora penelope, Discoporella cookae and Cupuladria biporosa, respectively. Intron-encoded protein domains reverse transcriptase and intron maturase (RVT-IM) were identified in all species. Introns in E. vieirai and P. penelope had conserved Group II intron ribozyme domains V and VI. Conserved domains were lacking from introns in D. cookae and C. biporosa, preventing their further categorization. Putative origins of metazoan introns were explored in a phylogenetic context, using an up-to-date alignment of mitochondrial RVT-IM domains. Results confirmed previous findings of multiple origins of annelid, placozoan and sponge RVT-IM domains and provided evidence for common intron donor sources across metazoan phyla. Our results corroborate growing evidence that some metazoans with regenerative abilities (i.e. placozoans, sponges, annelids and bryozoans) are susceptible to intron integration, most likely via horizontal gene transfer.
Collapse
|
17
|
Gophna U, Altman-Price N. Horizontal Gene Transfer in Archaea-From Mechanisms to Genome Evolution. Annu Rev Microbiol 2022; 76:481-502. [PMID: 35667126 DOI: 10.1146/annurev-micro-040820-124627] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Archaea remains the least-studied and least-characterized domain of life despite its significance not just to the ecology of our planet but also to the evolution of eukaryotes. It is therefore unsurprising that research into horizontal gene transfer (HGT) in archaea has lagged behind that of bacteria. Indeed, several archaeal lineages may owe their very existence to large-scale HGT events, and thus understanding both the molecular mechanisms and the evolutionary impact of HGT in archaea is highly important. Furthermore, some mechanisms of gene exchange, such as plasmids that transmit themselves via membrane vesicles and the formation of cytoplasmic bridges that allows transfer of both chromosomal and plasmid DNA, may be archaea specific. This review summarizes what we know about HGT in archaea, and the barriers that restrict it, highlighting exciting recent discoveries and pointing out opportunities for future research. Expected final online publication date for the Annual Review of Microbiology, Volume 76 is September 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
Collapse
Affiliation(s)
- Uri Gophna
- The Shmunis School of Biomedicine and Cancer Research, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel; ,
| | - Neta Altman-Price
- The Shmunis School of Biomedicine and Cancer Research, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel; , .,Department of Natural and Life Sciences, The Open University of Israel, Raanana, Israel
| |
Collapse
|
18
|
Macadangdang BR, Makanani SK, Miller JF. Accelerated Evolution by Diversity-Generating Retroelements. Annu Rev Microbiol 2022; 76:389-411. [PMID: 35650669 DOI: 10.1146/annurev-micro-030322-040423] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Diversity-generating retroelements (DGRs) create vast amounts of targeted, functional diversity by facilitating the rapid evolution of ligand-binding protein domains. Thousands of DGRs have been identified in bacteria, archaea, and their respective viruses. They are broadly distributed throughout the microbial world, with enrichment observed in certain taxa and environments. The diversification machinery works through a novel mechanism termed mutagenic retrohoming, whereby nucleotide sequence information is copied from an invariant DNA template repeat (TR) into an RNA intermediate, selectively mutagenized at TR adenines during cDNA synthesis by a DGR-encoded reverse transcriptase, and transferred to a variable repeat (VR) region within a variable-protein gene (54). This unidirectional flow of information leaves TR-DNA sequences unmodified, allowing for repeated rounds of mutagenic retrohoming to optimize variable-protein function. DGR target genes are often modular and can encode one or more of a wide variety of discrete functional domains appended to a diversifiable ligand-binding motif. Bacterial variable proteins often localize to cell surfaces, although a subset appear to be cytoplasmic, while phage-encoded DGRs commonly diversify tail fiber-associated receptor-binding proteins. Here, we provide a comprehensive review of the mechanism and consequences of accelerated protein evolution by these unique and beneficial genetic elements. Expected final online publication date for the Annual Review of Microbiology, Volume 76 is September 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
Collapse
Affiliation(s)
- Benjamin R Macadangdang
- Division of Neonatology and Developmental Biology, Department of Pediatrics, David Geffen School of Medicine, University of California, Los Angeles, California, USA; .,California NanoSystems Institute, University of California, Los Angeles, California, USA
| | - Sara K Makanani
- California NanoSystems Institute, University of California, Los Angeles, California, USA.,Department of Ecology and Evolutionary Biology, University of California, Los Angeles, California, USA; .,Department of Microbiology, Immunology and Molecular Genetics, David Geffen School of Medicine, University of California, Los Angeles, California, USA;
| | - Jeff F Miller
- California NanoSystems Institute, University of California, Los Angeles, California, USA.,Department of Microbiology, Immunology and Molecular Genetics, David Geffen School of Medicine, University of California, Los Angeles, California, USA; .,Molecular Biology Institute, University of California, Los Angeles, California, USA
| |
Collapse
|
19
|
Pan L, Luo Y, Wang J, Li X, Tang B, Yang H, Hou X, Liu F, Zou X. Evolution and functional diversification of catalase genes in the green lineage. BMC Genomics 2022; 23:411. [PMID: 35650553 PMCID: PMC9158360 DOI: 10.1186/s12864-022-08621-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Accepted: 05/09/2022] [Indexed: 11/10/2022] Open
Abstract
Background Catalases (CATs) break down hydrogen peroxide into water and oxygen to prevent cellular oxidative damage, and play key roles in the development, biotic and abiotic stresses of plants. However, the evolutionary relationships of the plant CAT gene family have not been systematically reported. Results Here, we conducted genome-wide comparative, phylogenetic, and structural analyses of CAT orthologs from 29 out of 31 representative green lineage species to characterize the evolution and functional diversity of CATs. We found that CAT genes in land plants were derived from core chlorophytes and detected a lineage-specific loss of CAT genes in Fabaceae, suggesting that the CAT genes in this group possess divergent functions. All CAT genes were split into three major groups (group α, β1, and β2) based on the phylogeny. CAT genes were transferred from bacteria to core chlorophytes and charophytes by lateral gene transfer, and this led to the independent evolution of two types of CAT genes: α and β types. Ten common motifs were detected in both α and β groups, and β CAT genes had five unique motifs, respectively. The findings of our study are inconsistent with two previous hypotheses proposing that (i) new CAT genes are acquired through intron loss and that (ii) the Cys-343 residue is highly conserved in plants. We found that new CAT genes in most higher plants were produced through intron acquisition and that the Cys-343 residue was only present in monocots, Brassicaceae and Pp_CatX7 in P. patens, which indicates the functional specificity of the CATs in these three lineages. Finally, our finding that CAT genes show high overall sequence identity but that individual CAT genes showed developmental stage and organ-specific expression patterns suggests that CAT genes have functionally diverged independently. Conclusions Overall, our analyses of the CAT gene family provide new insights into their evolution and functional diversification in green lineage species. Supplementary Information The online version contains supplementary material available at 10.1186/s12864-022-08621-6.
Collapse
|
20
|
Benler S, Koonin EV. Recruitment of Mobile Genetic Elements for Diverse Cellular Functions in Prokaryotes. Front Mol Biosci 2022; 9:821197. [PMID: 35402511 PMCID: PMC8987985 DOI: 10.3389/fmolb.2022.821197] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Accepted: 02/08/2022] [Indexed: 12/15/2022] Open
Abstract
Prokaryotic genomes are replete with mobile genetic elements (MGE) that span a continuum of replication autonomy. On numerous occasions during microbial evolution, diverse MGE lose their autonomy altogether but, rather than being quickly purged from the host genome, assume a new function that benefits the host, rendering the immobilized MGE subject to purifying selection, and resulting in its vertical inheritance. This mini-review highlights the diversity of the repurposed (exapted) MGE as well as the plethora of cellular functions that they perform. The principal contribution of the exaptation of MGE and their components is to the prokaryotic functional systems involved in biological conflicts, and in particular, defense against viruses and other MGE. This evolutionary entanglement between MGE and defense systems appears to stem both from mechanistic similarities and from similar evolutionary predicaments whereby both MGEs and defense systems tend to incur fitness costs to the hosts and thereby evolve mechanisms for survival including horizontal mobility, causing host addiction, and exaptation for functions beneficial to the host. The examples discussed demonstrate that the identity of an MGE, overall mobility and relationship with the host cell (mutualistic, symbiotic, commensal, or parasitic) are all factors that affect exaptation.
Collapse
|
21
|
Prince S, Munoz C, Filion-Bienvenue F, Rioux P, Sarrasin M, Lang BF. Refining Mitochondrial Intron Classification With ERPIN: Identification Based on Conservation of Sequence Plus Secondary Structure Motifs. Front Microbiol 2022; 13:866187. [PMID: 35369492 PMCID: PMC8971849 DOI: 10.3389/fmicb.2022.866187] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2022] [Accepted: 02/28/2022] [Indexed: 12/02/2022] Open
Abstract
Mitochondrial genomes—in particular those of fungi—often encode genes with a large number of Group I and Group II introns that are conserved at both the sequence and the RNA structure level. They provide a rich resource for the investigation of intron and gene structure, self- and protein-guided splicing mechanisms, and intron evolution. Yet, the degree of sequence conservation of introns is limited, and the primary sequence differs considerably among the distinct intron sub-groups. It makes intron identification, classification, structural modeling, and the inference of gene models a most challenging and error-prone task—frequently passed on to an “expert” for manual intervention. To reduce the need for manual curation of intron structures and mitochondrial gene models, computational methods using ERPIN sequence profiles were initially developed in 2007. Here we present a refinement of search models and alignments using the now abundant publicly available fungal mtDNA sequences. In addition, we have tested in how far members of the originally proposed sub-groups are clearly distinguished and validated by our computational approach. We confirm clearly distinct mitochondrial Group I sub-groups IA1, IA3, IB3, IC1, IC2, and ID. Yet, IB1, IB2, and IB4 ERPIN models are overlapping substantially in predictions, and are therefore combined and reported as IB. We have further explored the conversion of our ERPIN profiles into covariance models (CM). Current limitations and prospects of the CM approach will be discussed.
Collapse
|
22
|
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.
Collapse
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
| |
Collapse
|
23
|
Wang X, Wang J, Li S, Lu C, Sui N. An overview of RNA splicing and functioning of splicing factors in land plant chloroplasts. RNA Biol 2022; 19:897-907. [PMID: 35811474 PMCID: PMC9275481 DOI: 10.1080/15476286.2022.2096801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
RNA splicing refers to a process by which introns of a pre-mRNA are excised and the exons at both ends are joined together. Chloroplast introns are inherently self-splicing ribozymes, but over time, they have lost self-splicing ability due to the degeneration of intronic elements. Thus, the splicing of chloroplast introns relies heavily on nuclear-encoded splicing factors, which belong to diverse protein families. Different splicing factors and their shared intron targets are supposed to form ribonucleoprotein particles (RNPs) to facilitate intron splicing. As characterized in a previous review, around 14 chloroplast intron splicing factors were identified until 2010. However, only a few genetic and biochemical evidence has shown that these splicing factors are required for the splicing of one or several introns. The roles of splicing factors are generally believed to facilitate intron folding; however, the precise role of each protein in RNA splicing remains ambiguous. This may be because the precise binding site of most of these splicing factors remains unexplored. In the last decade, several new splicing factors have been identified. Also, several splicing factors were found to bind to specific sequences within introns, which enhanced the understanding of splicing factors. Here, we summarize recent progress on the splicing factors in land plant chloroplasts and discuss their possible roles in chloroplast RNA splicing based on previous studies.
Collapse
Affiliation(s)
- Xuemei Wang
- Shandong Provincial Key Laboratory of Plant Stress, College of Life Sciences, Shandong Normal University, Jinan, Western Shandong, China
| | - Jingyi Wang
- Shandong Provincial Key Laboratory of Plant Stress, College of Life Sciences, Shandong Normal University, Jinan, Western Shandong, China
| | - Simin Li
- Shandong Provincial Key Laboratory of Plant Stress, College of Life Sciences, Shandong Normal University, Jinan, Western Shandong, China
| | - Congming Lu
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Taian, Western Shandong, China
| | - Na Sui
- Shandong Provincial Key Laboratory of Plant Stress, College of Life Sciences, Shandong Normal University, Jinan, Western Shandong, China
| |
Collapse
|
24
|
Steffen K, Laborde Q, Gunasekera S, Payne CD, Rosengren KJ, Riesgo A, Göransson U, Cárdenas P. Barrettides: A Peptide Family Specifically Produced by the Deep-Sea Sponge Geodia barretti. JOURNAL OF NATURAL PRODUCTS 2021; 84:3138-3146. [PMID: 34874154 PMCID: PMC8713285 DOI: 10.1021/acs.jnatprod.1c00938] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Indexed: 05/16/2023]
Abstract
Natural product discovery by isolation and structure elucidation is a laborious task often requiring ample quantities of biological starting material and frequently resulting in the rediscovery of previously known compounds. However, peptides are a compound class amenable to an alternative genomic, transcriptomic, and in silico discovery route by similarity searches of known peptide sequences against sequencing data. Based on the sequences of barrettides A and B, we identified five new barrettide sequences (barrettides C-G) predicted from the North Atlantic deep-sea demosponge Geodia barretti (Geodiidae). We synthesized, folded, and investigated one of the newly described barrettides, barrettide C (NVVPCFCVEDETSGAKTCIPDNCDASRGTNP, disulfide connectivity I-IV, II-III). Co-elution experiments of synthetic and sponge-derived barrettide C confirmed its native conformation. NMR spectroscopy and the anti-biofouling activity on larval settlement of the bay barnacle Amphibalanus improvisus (IC50 0.64 μM) show that barrettide C is highly similar to barrettides A and B in both structure and function. Several lines of evidence suggest that barrettides are produced by the sponge itself and not one of its microbial symbionts.
Collapse
Affiliation(s)
- Karin Steffen
- Pharmacognosy,
Department of Pharmaceutical Biosciences, Biomedical Centre, Uppsala University, Husargatan 3, 751
23 Uppsala, Sweden
| | - Quentin Laborde
- Pharmacognosy,
Department of Pharmaceutical Biosciences, Biomedical Centre, Uppsala University, Husargatan 3, 751
23 Uppsala, Sweden
| | - Sunithi Gunasekera
- Pharmacognosy,
Department of Pharmaceutical Biosciences, Biomedical Centre, Uppsala University, Husargatan 3, 751
23 Uppsala, Sweden
| | - Colton D. Payne
- School
of Biomedical Sciences, The University of
Queensland, Brisbane, QLD 4072, Australia
| | - K. Johan Rosengren
- School
of Biomedical Sciences, The University of
Queensland, Brisbane, QLD 4072, Australia
| | - Ana Riesgo
- Department
of Life Sciences, The Natural History Museum, Cromwell Road, London SW7 5BD, United
Kingdom
- Department
of Biodiversity and Evolutionary Biology, Museo Nacional de Ciencias Naturales−CSIC, Calle José Gutiérrez Abascal 2, 28006, Madrid, Spain
| | - Ulf Göransson
- Pharmacognosy,
Department of Pharmaceutical Biosciences, Biomedical Centre, Uppsala University, Husargatan 3, 751
23 Uppsala, Sweden
| | - Paco Cárdenas
- Pharmacognosy,
Department of Pharmaceutical Biosciences, Biomedical Centre, Uppsala University, Husargatan 3, 751
23 Uppsala, Sweden
| |
Collapse
|
25
|
Fonseca PLC, De-Paula RB, Araújo DS, Tomé LMR, Mendes-Pereira T, Rodrigues WFC, Del-Bem LE, Aguiar ERGR, Góes-Neto A. Global Characterization of Fungal Mitogenomes: New Insights on Genomic Diversity and Dynamism of Coding Genes and Accessory Elements. Front Microbiol 2021; 12:787283. [PMID: 34925295 PMCID: PMC8672057 DOI: 10.3389/fmicb.2021.787283] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 11/11/2021] [Indexed: 01/13/2023] Open
Abstract
Fungi comprise a great diversity of species with distinct ecological functions and lifestyles. Similar to other eukaryotes, fungi rely on interactions with prokaryotes and one of the most important symbiotic events was the acquisition of mitochondria. Mitochondria are organelles found in eukaryotic cells whose main function is to generate energy through aerobic respiration. Mitogenomes (mtDNAs) are double-stranded circular or linear DNA from mitochondria that may contain core genes and accessory elements that can be replicated, transcribed, and independently translated from the nuclear genome. Despite their importance, investigative studies on the diversity of fungal mitogenomes are scarce. Herein, we have evaluated 788 curated fungal mitogenomes available at NCBI database to assess discrepancies and similarities among them and to better understand the mechanisms involved in fungal mtDNAs variability. From a total of 12 fungal phyla, four do not have any representative with available mitogenomes, which highlights the underrepresentation of some groups in the current available data. We selected representative and non-redundant mitogenomes based on the threshold of 90% similarity, eliminating 81 mtDNAs. Comparative analyses revealed considerable size variability of mtDNAs with a difference of up to 260 kb in length. Furthermore, variation in mitogenome length and genomic composition are generally related to the number and length of accessory elements (introns, HEGs, and uORFs). We identified an overall average of 8.0 (0–39) introns, 8.0 (0–100) HEGs, and 8.2 (0–102) uORFs per genome, with high variation among phyla. Even though the length of the core protein-coding genes is considerably conserved, approximately 36.3% of the mitogenomes evaluated have at least one of the 14 core coding genes absent. Also, our results revealed that there is not even a single gene shared among all mitogenomes. Other unusual genes in mitogenomes were also detected in many mitogenomes, such as dpo and rpo, and displayed diverse evolutionary histories. Altogether, the results presented in this study suggest that fungal mitogenomes are diverse, contain accessory elements and are absent of a conserved gene that can be used for the taxonomic classification of the Kingdom Fungi.
Collapse
Affiliation(s)
- Paula L C Fonseca
- Department of Genetics, Ecology and Evolution, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil.,Department of Biological Science (DCB), Center of Biotechnology and Genetics (CBG), Universidade Estadual de Santa Cruz (UESC), Ilhéus, Brazil
| | - Ruth B De-Paula
- Graduate School of Biomedical Sciences, Baylor College of Medicine, Houston, TX, United States
| | - Daniel S Araújo
- Program in Bioinformatics, Loyola University Chicago, Chicago, IL, United States
| | - Luiz Marcelo Ribeiro Tomé
- Molecular and Computational Biology of Fungi Laboratory, Department of Microbiology, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Thairine Mendes-Pereira
- Molecular and Computational Biology of Fungi Laboratory, Department of Microbiology, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | | | - Luiz-Eduardo Del-Bem
- Program of Bioinformatics, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil.,Department of Botany, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Eric R G R Aguiar
- Department of Biological Science (DCB), Center of Biotechnology and Genetics (CBG), Universidade Estadual de Santa Cruz (UESC), Ilhéus, Brazil
| | - Aristóteles Góes-Neto
- Molecular and Computational Biology of Fungi Laboratory, Department of Microbiology, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil.,Program of Bioinformatics, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| |
Collapse
|
26
|
Patinios C, Creutzburg SCA, Arifah AQ, Adiego-Pérez B, Gyimah E, Ingham C, Kengen SWM, van der Oost J, Staals RHJ. Streamlined CRISPR genome engineering in wild-type bacteria using SIBR-Cas. Nucleic Acids Res 2021; 49:11392-11404. [PMID: 34614191 PMCID: PMC8565351 DOI: 10.1093/nar/gkab893] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 09/16/2021] [Accepted: 09/20/2021] [Indexed: 11/13/2022] Open
Abstract
CRISPR-Cas is a powerful tool for genome editing in bacteria. However, its efficacy is dependent on host factors (such as DNA repair pathways) and/or exogenous expression of recombinases. In this study, we mitigated these constraints by developing a simple and widely applicable genome engineering tool for bacteria which we termed SIBR-Cas (Self-splicing Intron-Based Riboswitch-Cas). SIBR-Cas was generated from a mutant library of the theophylline-dependent self-splicing T4 td intron that allows for tight and inducible control over CRISPR-Cas counter-selection. This control delays CRISPR-Cas counter-selection, granting more time for the editing event (e.g. by homologous recombination) to occur. Without the use of exogenous recombinases, SIBR-Cas was successfully applied to knock-out several genes in three wild-type bacteria species (Escherichia coli MG1655, Pseudomonas putida KT2440 and Flavobacterium IR1) with poor homologous recombination systems. Compared to other genome engineering tools, SIBR-Cas is simple, tightly regulated and widely applicable for most (non-model) bacteria. Furthermore, we propose that SIBR can have a wider application as a simple gene expression and gene regulation control mechanism for any gene or RNA of interest in bacteria.
Collapse
Affiliation(s)
- Constantinos Patinios
- Laboratory of Microbiology, Wageningen University and Research, Stippeneng 4, 6708 WE, Wageningen, The Netherlands
| | - Sjoerd C A Creutzburg
- Laboratory of Microbiology, Wageningen University and Research, Stippeneng 4, 6708 WE, Wageningen, The Netherlands
| | - Adini Q Arifah
- Laboratory of Microbiology, Wageningen University and Research, Stippeneng 4, 6708 WE, Wageningen, The Netherlands
| | - Belén Adiego-Pérez
- Laboratory of Microbiology, Wageningen University and Research, Stippeneng 4, 6708 WE, Wageningen, The Netherlands
| | - Evans A Gyimah
- Laboratory of Microbiology, Wageningen University and Research, Stippeneng 4, 6708 WE, Wageningen, The Netherlands
| | - Colin J Ingham
- Hoekmine Besloten Vennootschap, Kenniscentrum Technologie en Innovatie, Hogeschool Utrecht, 3584 CS, Utrecht, The Netherlands
| | - Servé W M Kengen
- Laboratory of Microbiology, Wageningen University and Research, Stippeneng 4, 6708 WE, Wageningen, The Netherlands
| | - John van der Oost
- Laboratory of Microbiology, Wageningen University and Research, Stippeneng 4, 6708 WE, Wageningen, The Netherlands
| | - Raymond H J Staals
- Laboratory of Microbiology, Wageningen University and Research, Stippeneng 4, 6708 WE, Wageningen, The Netherlands
| |
Collapse
|
27
|
Douglas GM, Shapiro BJ. Genic Selection Within Prokaryotic Pangenomes. Genome Biol Evol 2021; 13:6402011. [PMID: 34665261 PMCID: PMC8598171 DOI: 10.1093/gbe/evab234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/14/2021] [Indexed: 11/13/2022] Open
Abstract
Understanding the evolutionary forces shaping prokaryotic pangenome structure is a major goal of microbial evolution research. Recent work has highlighted that a substantial proportion of accessory genes appear to confer niche-specific adaptations. This work has primarily focused on selection acting at the level of individual cells. Herein, we discuss a lower level of selection that also contributes to pangenome variation: genic selection. This refers to cases where genetic elements, rather than individual cells, are the entities under selection. The clearest examples of this form of selection are selfish mobile genetic elements, which are those that have either a neutral or a deleterious effect on host fitness. We review the major classes of these and other mobile elements and discuss the characteristic features of such elements that could be under genic selection. We also discuss how genetic elements that are beneficial to hosts can also be under genic selection, a scenario that may be more prevalent but not widely appreciated, because disentangling the effects of selection at different levels (i.e., organisms vs. genes) is challenging. Nonetheless, an appreciation for the potential action and implications of genic selection is important to better understand the evolution of prokaryotic pangenomes.
Collapse
Affiliation(s)
- Gavin M Douglas
- Department of Microbiology and Immunology, McGill University, Montréal, Québec, Canada
| | - B Jesse Shapiro
- Department of Microbiology and Immunology, McGill University, Montréal, Québec, Canada
| |
Collapse
|
28
|
Alonso D, Mondragón A. Mechanisms of catalytic RNA molecules. Biochem Soc Trans 2021; 49:1529-1535. [PMID: 34415304 PMCID: PMC10583251 DOI: 10.1042/bst20200465] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 07/20/2021] [Accepted: 07/28/2021] [Indexed: 11/17/2022]
Abstract
Ribozymes are folded catalytic RNA molecules that perform important biological functions. Since the discovery of the first RNA with catalytic activity in 1982, a large number of ribozymes have been reported. While most catalytic RNA molecules act alone, some RNA-based catalysts, such as RNase P, the ribosome, and the spliceosome, need protein components to perform their functions in the cell. In the last decades, the structure and mechanism of several ribozymes have been studied in detail. Aside from the ribosome, which catalyzes peptide bond formation during protein synthesis, the majority of known ribozymes carry out mostly phosphoryl transfer reactions, notably trans-esterification or hydrolysis reactions. In this review, we describe the main features of the mechanisms of various types of ribozymes that can function with or without the help of proteins to perform their biological functions.
Collapse
Affiliation(s)
- Dulce Alonso
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, U.S.A
| | - Alfonso Mondragón
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, U.S.A
| |
Collapse
|
29
|
Mukhopadhyay J, Hausner G. Organellar Introns in Fungi, Algae, and Plants. Cells 2021; 10:cells10082001. [PMID: 34440770 PMCID: PMC8393795 DOI: 10.3390/cells10082001] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 07/31/2021] [Accepted: 08/05/2021] [Indexed: 12/16/2022] Open
Abstract
Introns are ubiquitous in eukaryotic genomes and have long been considered as ‘junk RNA’ but the huge energy expenditure in their transcription, removal, and degradation indicate that they may have functional significance and can offer evolutionary advantages. In fungi, plants and algae introns make a significant contribution to the size of the organellar genomes. Organellar introns are classified as catalytic self-splicing introns that can be categorized as either Group I or Group II introns. There are some biases, with Group I introns being more frequently encountered in fungal mitochondrial genomes, whereas among plants Group II introns dominate within the mitochondrial and chloroplast genomes. Organellar introns can encode a variety of proteins, such as maturases, homing endonucleases, reverse transcriptases, and, in some cases, ribosomal proteins, along with other novel open reading frames. Although organellar introns are viewed to be ribozymes, they do interact with various intron- or nuclear genome-encoded protein factors that assist in the intron RNA to fold into competent splicing structures, or facilitate the turn-over of intron RNAs to prevent reverse splicing. Organellar introns are also known to be involved in non-canonical splicing, such as backsplicing and trans-splicing which can result in novel splicing products or, in some instances, compensate for the fragmentation of genes by recombination events. In organellar genomes, Group I and II introns may exist in nested intronic arrangements, such as introns within introns, referred to as twintrons, where splicing of the external intron may be dependent on splicing of the internal intron. These nested or complex introns, with two or three-component intron modules, are being explored as platforms for alternative splicing and their possible function as molecular switches for modulating gene expression which could be potentially applied towards heterologous gene expression. This review explores recent findings on organellar Group I and II introns, focusing on splicing and mobility mechanisms aided by associated intron/nuclear encoded proteins and their potential roles in organellar gene expression and cross talk between nuclear and organellar genomes. Potential application for these types of elements in biotechnology are also discussed.
Collapse
MESH Headings
- Evolution, Molecular
- Gene Expression Regulation, Fungal
- Gene Expression Regulation, Plant
- Genome, Fungal
- Genome, Plant
- Introns
- Organelles/genetics
- Organelles/metabolism
- RNA Splicing
- RNA Stability
- RNA, Algal/genetics
- RNA, Algal/metabolism
- RNA, Fungal/genetics
- RNA, Fungal/metabolism
- RNA, Plant/genetics
- RNA, Plant/metabolism
- RNA, Untranslated/genetics
- RNA, Untranslated/metabolism
- Transcription, Genetic
Collapse
|
30
|
Megarioti AH, Kouvelis VN. The Coevolution of Fungal Mitochondrial Introns and Their Homing Endonucleases (GIY-YIG and LAGLIDADG). Genome Biol Evol 2021; 12:1337-1354. [PMID: 32585032 PMCID: PMC7487136 DOI: 10.1093/gbe/evaa126] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/17/2020] [Indexed: 12/21/2022] Open
Abstract
Fungal mitochondrial (mt) genomes exhibit great diversity in size which is partially attributed to their variable intergenic regions and most importantly to the inclusion of introns within their genes. These introns belong to group I or II, and both of them are self-splicing. The majority of them carry genes encoding homing endonucleases, either LAGLIDADG or GIY-YIG. In this study, it was found that these intronic homing endonucleases genes (HEGs) may originate from mt free-standing open reading frames which can be found nowadays in species belonging to Early Diverging Fungi as “living fossils.” A total of 487 introns carrying HEGs which were located in the publicly available mt genomes of representative species belonging to orders from all fungal phyla was analyzed. Their distribution in the mt genes, their insertion target sequence, and the phylogenetic analyses of the HEGs showed that these introns along with their HEGs form a composite structure in which both selfish elements coevolved. The invasion of the ancestral free-standing HEGs in the introns occurred through a perpetual mechanism, called in this study as “aenaon” hypothesis. It is based on recombination, transpositions, and horizontal gene transfer events throughout evolution. HEGs phylogenetically clustered primarily according to their intron hosts and secondarily to the mt genes carrying the introns and their HEGs. The evolutionary models created revealed an “intron-early” evolution which was enriched by “intron-late” events through many different independent recombinational events which resulted from both vertical and horizontal gene transfers.
Collapse
Affiliation(s)
- Amalia H Megarioti
- Department of Genetics and Biotechnology, Faculty of Biology, National and Kapodistrian University of Athens, Greece
| | - Vassili N Kouvelis
- Department of Genetics and Biotechnology, Faculty of Biology, National and Kapodistrian University of Athens, Greece
| |
Collapse
|
31
|
Mayers CG, Harrington TC, Wai A, Hausner G. Recent and Ongoing Horizontal Transfer of Mitochondrial Introns Between Two Fungal Tree Pathogens. Front Microbiol 2021; 12:656609. [PMID: 34149643 PMCID: PMC8208691 DOI: 10.3389/fmicb.2021.656609] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Accepted: 04/09/2021] [Indexed: 11/23/2022] Open
Abstract
Two recently introduced fungal plant pathogens (Ceratocystis lukuohia and Ceratocystis huliohia) are responsible for Rapid ‘ōhi‘a Death (ROD) in Hawai‘i. Despite being sexually incompatible, the two pathogens often co-occur in diseased ‘ōhi‘a sapwood, where genetic interaction is possible. We sequenced and annotated 33 mitochondrial genomes of the two pathogens and related species, and investigated 35 total Ceratocystis mitogenomes. Ten mtDNA regions [one group I intron, seven group II introns, and two autonomous homing endonuclease (HE) genes] were heterogeneously present in C. lukuohia mitogenomes, which were otherwise identical. Molecular surveys with specific primers showed that the 10 regions had uneven geographic distribution amongst populations of C. lukuohia. Conversely, identical orthologs of each region were present in every studied isolate of C. huliohia regardless of geographical origin. Close relatives of C. lukuohia lacked or, rarely, had few and dissimilar orthologs of the 10 regions, whereas most relatives of C. huliohia had identical or nearly identical orthologs. Each region included or worked in tandem with HE genes or reverse transcriptase/maturases that could facilitate interspecific horizontal transfers from intron-minus to intron-plus alleles. These results suggest that the 10 regions originated in C. huliohia and are actively moving to populations of C. lukuohia, perhaps through transient cytoplasmic contact of hyphal tips (anastomosis) in the wound surface of ‘ōhi‘a trees. Such contact would allow for the transfer of mitochondria followed by mitochondrial fusion or cytoplasmic exchange of intron intermediaries, which suggests that further genomic interaction may also exist between the two pathogens.
Collapse
Affiliation(s)
- Chase G Mayers
- Department of Plant Pathology and Microbiology, Iowa State University, Ames, IA, United States
| | - Thomas C Harrington
- Department of Plant Pathology and Microbiology, Iowa State University, Ames, IA, United States
| | - Alvan Wai
- Department of Microbiology, University of Manitoba, Winnipeg, MB, Canada
| | - Georg Hausner
- Department of Microbiology, University of Manitoba, Winnipeg, MB, Canada
| |
Collapse
|
32
|
RNA-Targeting Splicing Modifiers: Drug Development and Screening Assays. Molecules 2021; 26:molecules26082263. [PMID: 33919699 PMCID: PMC8070285 DOI: 10.3390/molecules26082263] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 04/05/2021] [Accepted: 04/09/2021] [Indexed: 02/06/2023] Open
Abstract
RNA splicing is an essential step in producing mature messenger RNA (mRNA) and other RNA species. Harnessing RNA splicing modifiers as a new pharmacological modality is promising for the treatment of diseases caused by aberrant splicing. This drug modality can be used for infectious diseases by disrupting the splicing of essential pathogenic genes. Several antisense oligonucleotide splicing modifiers were approved by the U.S. Food and Drug Administration (FDA) for the treatment of spinal muscular atrophy (SMA) and Duchenne muscular dystrophy (DMD). Recently, a small-molecule splicing modifier, risdiplam, was also approved for the treatment of SMA, highlighting small molecules as important warheads in the arsenal for regulating RNA splicing. The cellular targets of these approved drugs are all mRNA precursors (pre-mRNAs) in human cells. The development of novel RNA-targeting splicing modifiers can not only expand the scope of drug targets to include many previously considered “undruggable” genes but also enrich the chemical-genetic toolbox for basic biomedical research. In this review, we summarized known splicing modifiers, screening methods for novel splicing modifiers, and the chemical space occupied by the small-molecule splicing modifiers.
Collapse
|
33
|
Panchapakesan SSS, Breaker RR. The case of the missing allosteric ribozymes. Nat Chem Biol 2021; 17:375-382. [PMID: 33495645 PMCID: PMC8880209 DOI: 10.1038/s41589-020-00713-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Accepted: 11/13/2020] [Indexed: 01/28/2023]
Abstract
The RNA World theory encompasses the hypothesis that sophisticated ribozymes and riboswitches were the primary drivers of metabolic processes in ancient organisms. Several types of catalytic RNAs and many classes of ligand-sensing RNA switches still exist in modern cells. Curiously, allosteric ribozymes formed by the merger of RNA enzyme and RNA switch components are largely absent in today's biological systems. This is true despite the striking abundances of various classes of both self-cleaving ribozymes and riboswitch aptamers. Here we present the known types of ligand-controlled ribozymes and riboswitches and discuss the possible reasons why fused ribozyme-aptamer constructs have been disfavored through evolution.
Collapse
Affiliation(s)
- Shanker S. S. Panchapakesan
- Department of Molecular, Cellular and Developmental
Biology, Yale University, P.O. Box 208103, New Haven, CT 06520-8103, USA
| | - Ronald R. Breaker
- Department of Molecular, Cellular and Developmental
Biology, Yale University, P.O. Box 208103, New Haven, CT 06520-8103, USA.,Howard Hughes Medical Institute, Yale University, P.O. Box
208103, New Haven, CT 06520-8103, USA.,Department of Molecular Biophysics and Biochemistry, Yale
University, P.O. Box 208103, New Haven, CT 06520-8103, USA
| |
Collapse
|
34
|
Wachter S, Hicks LD, Raghavan R, Minnick MF. Novel small RNAs expressed by Bartonella bacilliformis under multiple conditions reveal potential mechanisms for persistence in the sand fly vector and human host. PLoS Negl Trop Dis 2020; 14:e0008671. [PMID: 33216745 PMCID: PMC7717549 DOI: 10.1371/journal.pntd.0008671] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 12/04/2020] [Accepted: 10/06/2020] [Indexed: 11/30/2022] Open
Abstract
Bartonella bacilliformis, the etiological agent of Carrión’s disease, is a Gram-negative, facultative intracellular alphaproteobacterium. Carrión’s disease is an emerging but neglected tropical illness endemic to Peru, Colombia, and Ecuador. B. bacilliformis is spread between humans through the bite of female phlebotomine sand flies. As a result, the pathogen encounters significant and repeated environmental shifts during its life cycle, including changes in pH and temperature. In most bacteria, small non-coding RNAs (sRNAs) serve as effectors that may post-transcriptionally regulate the stress response to such changes. However, sRNAs have not been characterized in B. bacilliformis, to date. We therefore performed total RNA-sequencing analyses on B. bacilliformis grown in vitro then shifted to one of ten distinct conditions that simulate various environments encountered by the pathogen during its life cycle. From this, we identified 160 sRNAs significantly expressed under at least one of the conditions tested. sRNAs included the highly-conserved tmRNA, 6S RNA, RNase P RNA component, SRP RNA component, ffH leader RNA, and the alphaproteobacterial sRNAs αr45 and speF leader RNA. In addition, 153 other potential sRNAs of unknown function were discovered. Northern blot analysis was used to confirm the expression of eight novel sRNAs. We also characterized a Bartonellabacilliformisgroup I intron (BbgpI) that disrupts an un-annotated tRNACCUArg gene and determined that the intron splices in vivo and self-splices in vitro. Furthermore, we demonstrated the molecular targeting of Bartonellabacilliformissmall RNA 9 (BbsR9) to transcripts of the ftsH, nuoF, and gcvT genes, in vitro. B. bacilliformis is a bacterial pathogen that is transmitted between humans by phlebotomine sand flies. Bacteria often express sRNAs to fine-tune the production of proteins involved in a wide array of biological processes. We cultured B. bacilliformis in vitro under standard conditions then shifted the pathogen for a period of time to ten distinct environments, including multiple temperatures, pH levels, and infections of human blood and human vascular endothelial cells. After RNA-sequencing, a manual transcriptome search identified 160 putative sRNAs, including seven highly-conserved sRNAs and 153 novel potential sRNAs. We then characterized two of the novel sRNAs, BbgpI and BbsR9. BbgpI is a group I intron (ribozyme) that self-splices and disrupts an unannotated gene coding for a transfer RNA (tRNACCUArg). BbsR9 is an intergenic sRNA expressed under conditions that simulate the sand fly. We found that BbsR9 targets transcripts of the ftsH, nuoF, and gcvT genes. Furthermore, we determined the specific sRNA-mRNA interactions responsible for BbsR9 binding to its target mRNAs through in vitro mutagenesis and binding assays.
Collapse
Affiliation(s)
- Shaun Wachter
- Program in Cellular, Molecular & Microbial Biology, Division of Biological Sciences, University of Montana, Missoula, Montana, United States of America
| | - Linda D. Hicks
- Program in Cellular, Molecular & Microbial Biology, Division of Biological Sciences, University of Montana, Missoula, Montana, United States of America
| | - Rahul Raghavan
- Department of Biology and Center for Life in Extreme Environments, Portland State University, Portland, Oregon, United States of America
| | - Michael F. Minnick
- Program in Cellular, Molecular & Microbial Biology, Division of Biological Sciences, University of Montana, Missoula, Montana, United States of America
- * E-mail:
| |
Collapse
|
35
|
Bramley JC, Yenkin AL, Zaydman MA, DiAntonio A, Milbrandt JD, Buchser WJ. Domain-centric database to uncover structure of minimally characterized viral genomes. Sci Data 2020; 7:202. [PMID: 32587259 PMCID: PMC7316859 DOI: 10.1038/s41597-020-0536-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Accepted: 05/01/2020] [Indexed: 02/06/2023] Open
Abstract
Protein domain-based approaches to analyzing sequence data are valuable tools for examining and exploring genomic architecture across genomes of different organisms. Here, we present a complete dataset of domains from the publicly available sequence data of 9,051 reference viral genomes. The data provided contain information such as sequence position and neighboring domains from 30,947 pHMM-identified domains from each reference viral genome. Domains were identified from viral whole-genome sequence using automated profile Hidden Markov Models (pHMM). This study also describes the framework for constructing "domain neighborhoods", as well as the dataset representing it. These data can be used to examine shared and differing domain architectures across viral genomes, to elucidate potential functional properties of genes, and potentially to classify viruses.
Collapse
Affiliation(s)
- John C Bramley
- Department of Genetics, Washington University School of Medicine, St Louis, MO, 63110, USA
| | - Alex L Yenkin
- Department of Genetics, Washington University School of Medicine, St Louis, MO, 63110, USA
| | - Mark A Zaydman
- Department of Pathology and Immunology, Washington University School of Medicine, St Louis, MO, 63110, USA
| | - Aaron DiAntonio
- Department of Genetics, Washington University School of Medicine, St Louis, MO, 63110, USA
- Department of Developmental Biology, Washington University School of Medicine in St. Louis, St. Louis, 63110, MO, USA
| | - Jeffrey D Milbrandt
- Department of Genetics, Washington University School of Medicine, St Louis, MO, 63110, USA
- Department of Pathology and Immunology, Washington University School of Medicine, St Louis, MO, 63110, USA
| | - William J Buchser
- Department of Genetics, Washington University School of Medicine, St Louis, MO, 63110, USA.
| |
Collapse
|
36
|
Cinget B, Bélanger RR. Discovery of new group I-D introns leads to creation of subtypes and link to an adaptive response of the mitochondrial genome in fungi. RNA Biol 2020; 17:1252-1260. [PMID: 32449459 PMCID: PMC7595605 DOI: 10.1080/15476286.2020.1763024] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Group I catalytic introns are widespread in bacterial, archaeal, viral, organellar, and some eukaryotic genomes, where they are reported to provide regulatory functions. The group I introns are currently divided into five types (A-E), which are themselves distributed into several subtypes, with the exception of group I type D intron (GI-D). GI-D introns belong to the rarest group with only 17 described to date, including only one with a putative role reported in fungi, where it would interfere with an adaptive response in the cytochrome b (COB) gene to quinone outside inhibitor (QoI) fungicide resistance. Using homology search methods taking into account both conserved sequences and RNA secondary structures, we analysed the mitochondrial genomes or COB genes of 169 fungal species, including some frequently under QoI selection pressure. These analyses have led to the identification of 216 novel GI-D introns, and the definition of three distinct subtypes, one of which being linked with a functional activity. We have further uncovered a homing site for this GI-D intron type, which helps refine the accepted model of quinone outside inhibitor resistance, whereby mobility of the intron across fungal mitochondrial genomes, would influence a fungus ability to develop resistance to QoIs.
Collapse
Affiliation(s)
- Benjamin Cinget
- Département de Phytologie, Faculty of Agriculture and Food Sciences, Centre de Recherche en Innovation des Végétaux (CRIV), Université Laval , Québec, Québec, Canada
| | - Richard R Bélanger
- Département de Phytologie, Faculty of Agriculture and Food Sciences, Centre de Recherche en Innovation des Végétaux (CRIV), Université Laval , Québec, Québec, Canada
| |
Collapse
|
37
|
Dujon B. Mitochondrial genetics revisited. Yeast 2020; 37:191-205. [DOI: 10.1002/yea.3445] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2019] [Revised: 10/05/2019] [Accepted: 10/08/2019] [Indexed: 12/17/2022] Open
Affiliation(s)
- Bernard Dujon
- Department Genomes and GeneticsInstitut Pasteur Paris France
| |
Collapse
|
38
|
Laforet M, McMurrough TA, Vu M, Brown CM, Zhang K, Junop MS, Gloor GB, Edgell DR. Modifying a covarying protein-DNA interaction changes substrate preference of a site-specific endonuclease. Nucleic Acids Res 2019; 47:10830-10841. [PMID: 31602462 PMCID: PMC6847045 DOI: 10.1093/nar/gkz866] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Revised: 09/17/2019] [Accepted: 10/09/2019] [Indexed: 12/23/2022] Open
Abstract
Identifying and validating intermolecular covariation between proteins and their DNA-binding sites can provide insights into mechanisms that regulate selectivity and starting points for engineering new specificity. LAGLIDADG homing endonucleases (meganucleases) can be engineered to bind non-native target sites for gene-editing applications, but not all redesigns successfully reprogram specificity. To gain a global overview of residues that influence meganuclease specificity, we used information theory to identify protein-DNA covariation. Directed evolution experiments of one predicted pair, 227/+3, revealed variants with surprising shifts in I-OnuI substrate preference at the central 4 bases where cleavage occurs. Structural studies showed significant remodeling distant from the covarying position, including restructuring of an inter-hairpin loop, DNA distortions near the scissile phosphates, and new base-specific contacts. Our findings are consistent with a model whereby the functional impacts of covariation can be indirectly propagated to neighboring residues outside of direct contact range, allowing meganucleases to adapt to target site variation and indirectly expand the sequence space accessible for cleavage. We suggest that some engineered meganucleases may have unexpected cleavage profiles that were not rationally incorporated during the design process.
Collapse
Affiliation(s)
- Marc Laforet
- Department of Biochemistry, Schulich School of Medicine and Dentistry, Western University, London, ON N6A 5C1, Canada
| | - Thomas A McMurrough
- Department of Biochemistry, Schulich School of Medicine and Dentistry, Western University, London, ON N6A 5C1, Canada
| | - Michael Vu
- Department of Biochemistry, Schulich School of Medicine and Dentistry, Western University, London, ON N6A 5C1, Canada
| | - Christopher M Brown
- Department of Biochemistry, Schulich School of Medicine and Dentistry, Western University, London, ON N6A 5C1, Canada
| | - Kun Zhang
- Department of Biochemistry, Schulich School of Medicine and Dentistry, Western University, London, ON N6A 5C1, Canada
| | - Murray S Junop
- Department of Biochemistry, Schulich School of Medicine and Dentistry, Western University, London, ON N6A 5C1, Canada
| | - Gregory B Gloor
- Department of Biochemistry, Schulich School of Medicine and Dentistry, Western University, London, ON N6A 5C1, Canada
| | - David R Edgell
- Department of Biochemistry, Schulich School of Medicine and Dentistry, Western University, London, ON N6A 5C1, Canada
| |
Collapse
|
39
|
Nawrocki EP, Jones TA, Eddy SR. Group I introns are widespread in archaea. Nucleic Acids Res 2019; 46:7970-7976. [PMID: 29788499 PMCID: PMC6125680 DOI: 10.1093/nar/gky414] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2018] [Accepted: 05/04/2018] [Indexed: 01/28/2023] Open
Abstract
Group I catalytic introns have been found in bacterial, viral, organellar, and some eukaryotic genomes, but not in archaea. All known archaeal introns are bulge-helix-bulge (BHB) introns, with the exception of a few group II introns. It has been proposed that BHB introns arose from extinct group I intron ancestors, much like eukaryotic spliceosomal introns are thought to have descended from group II introns. However, group I introns have little sequence conservation, making them difficult to detect with standard sequence similarity searches. Taking advantage of recent improvements in a computational homology search method that accounts for both conserved sequence and RNA secondary structure, we have identified 39 group I introns in a wide range of archaeal phyla, including examples of group I introns and BHB introns in the same host gene.
Collapse
Affiliation(s)
- Eric P Nawrocki
- National Center for Biotechnology Information, U.S. National Library of Medicine, Bethesda, MD 20894, USA
| | - Thomas A Jones
- Howard Hughes Medical Institute, Harvard University, Cambridge, USA.,Department of Molecular and Cellular Biology, Harvard University, Cambridge, USA
| | - Sean R Eddy
- Howard Hughes Medical Institute, Harvard University, Cambridge, USA.,Department of Molecular and Cellular Biology, Harvard University, Cambridge, USA.,School of Engineering and Applied Sciences, Harvard University, Cambridge, USA
| |
Collapse
|
40
|
Expanding the Diversity of Myoviridae Phages Infecting Lactobacillus plantarum-A Novel Lineage of Lactobacillus Phages Comprising Five New Members. Viruses 2019; 11:v11070611. [PMID: 31277436 PMCID: PMC6669764 DOI: 10.3390/v11070611] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 06/07/2019] [Accepted: 07/02/2019] [Indexed: 01/01/2023] Open
Abstract
Lactobacillus plantarum is a bacterium with probiotic properties and promising applications in the food industry and agriculture. So far, bacteriophages of this bacterium have been moderately addressed. We examined the diversity of five new L. plantarum phages via whole genome shotgun sequencing and in silico protein predictions. Moreover, we looked into their phylogeny and their potential genomic similarities to other complete phage genome records through extensive nucleotide and protein comparisons. These analyses revealed a high degree of similarity among the five phages, which extended to the vast majority of predicted virion-associated proteins. Based on these, we selected one of the phages as a representative and performed transmission electron microscopy and structural protein sequencing tests. Overall, the results suggested that the five phages belong to the family Myoviridae, they have a long genome of 137,973-141,344 bp, a G/C content of 36.3-36.6% that is quite distinct from their host's, and surprisingly, 7 to 15 tRNAs. Only an average 41/174 of their predicted genes were assigned a function. The comparative analyses unraveled considerable genetic diversity for the five L. plantarum phages in this study. Hence, the new genus "Semelevirus" was proposed, comprising exclusively of the five phages. This novel lineage of Lactobacillus phages provides further insight into the genetic heterogeneity of phages infecting Lactobacillus sp. The five new Lactobacillus phages have potential value for the development of more robust starters through, for example, the selection of mutants insensitive to phage infections. The five phages could also form part of phage cocktails, which producers would apply in different stages of L. plantarum fermentations in order to create a range of organoleptic outputs.
Collapse
|
41
|
Horizontally-acquired genetic elements in the mitochondrial genome of a centrohelid Marophrys sp. SRT127. Sci Rep 2019; 9:4850. [PMID: 30890720 PMCID: PMC6425028 DOI: 10.1038/s41598-019-41238-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Accepted: 03/04/2019] [Indexed: 01/06/2023] Open
Abstract
Mitochondrial genomes exhibit diverse features among eukaryotes in the aspect of gene content, genome structure, and the mobile genetic elements such as introns and plasmids. Although the number of published mitochondrial genomes is increasing at tremendous speed, those of several lineages remain unexplored. Here, we sequenced the complete mitochondrial genome of a unicellular heterotrophic eukaryote, Marophrys sp. SRT127 belonging to the Centroheliozoa, as the first report on this lineage. The circular-mapped mitochondrial genome, which is 113,062 bp in length, encodes 69 genes typically found in mitochondrial genomes. In addition, the Marophrys mitochondrial genome contains 19 group I introns. Of these, 11 introns have genes for homing endonuclease (HE) and phylogenetic analyses of HEs have shown that at least five Marophrys HEs are related to those in green algal plastid genomes, suggesting intron transfer between the Marophrys mitochondrion and green algal plastids. We also discovered a putative mitochondrial plasmid in linear form. Two genes encoded in the circular-mapped mitochondrial genome were found to share significant similarities to those in the linear plasmid, suggesting that the plasmid was integrated into the mitochondrial genome. These findings expand our knowledge on the diversity and evolution of the mobile genetic elements in mitochondrial genomes.
Collapse
|
42
|
Vasilyev N, Gao A, Serganov A. Noncanonical features and modifications on the 5'-end of bacterial sRNAs and mRNAs. WILEY INTERDISCIPLINARY REVIEWS. RNA 2019; 10:e1509. [PMID: 30276982 PMCID: PMC6657780 DOI: 10.1002/wrna.1509] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Revised: 09/05/2018] [Accepted: 09/17/2018] [Indexed: 12/20/2022]
Abstract
Although many eukaryotic transcripts contain cap structures, it has been long thought that bacterial RNAs do not carry any special modifications on their 5'-ends. In bacteria, primary transcripts are produced by transcription initiated with a nucleoside triphosphate and are therefore triphosphorylated on 5'-ends. Some transcripts are then processed by nucleases that yield monophosphorylated RNAs for specific cellular activities. Many primary transcripts are also converted to monophosphorylated species by removal of the terminal pyrophosphate for 5'-end-dependent degradation. Recent studies surprisingly revealed an expanded repertoire of chemical groups on 5'-ends of bacterial RNAs. In addition to mono- and triphosphorylated moieties, some mRNAs and sRNAs contain cap-like structures and diphosphates on their 5'-ends. Although incorporation and removal of these groups have become better understood in recent years, the physiological significance of these modifications remain obscure. This review highlights recent studies aimed at identification and elucidation of novel modifications on the 5'-ends of bacterial RNAs and discusses possible physiological applications of the modified RNAs. This article is categorized under: RNA Turnover and Surveillance > Regulation of RNA Stability RNA Structure and Dynamics > RNA Structure, Dynamics, and Chemistry RNA Processing > Capping and 5' End Modifications.
Collapse
Affiliation(s)
- Nikita Vasilyev
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, 550 First Avenue, New York, NY 10016, USA
| | - Ang Gao
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, 550 First Avenue, New York, NY 10016, USA
| | - Alexander Serganov
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, 550 First Avenue, New York, NY 10016, USA
| |
Collapse
|
43
|
Abstract
Bacterial noncoding RNA (ncRNA) classes longer than 200 nucleotides are rare but are responsible for performing some of the most fundamental tasks in living cells. RNAs such as 16S and 23S rRNA, group I and group II introns, RNase P ribozymes, transfer-messenger RNAs, and coenzyme B12 riboswitches are diverse in structure and accomplish biochemical functions that rival the activities of proteins. Over the last decade, a number of new classes of large ncRNAs have been uncovered in bacteria. A total of 21 classes with no established functions have been identified through the use of bioinformatics search strategies. Based on precedents for bacterial large ncRNAs performing sophisticated functions, it seems likely that some of these structured ncRNAs also will prove to carry out complex functions. Thus, determining their roles will provide a better understanding of fundamental biological processes. A few studies have produced data that provide clues to the purposes of some of these recently found classes, but the true functions of most classes remain mysterious.
Collapse
|
44
|
Mihăşan M, Babii C, Aslebagh R, Channaveerappa D, Dupree EJ, Darie CC. Exploration of Nicotine Metabolism in Paenarthrobacter nicotinovorans pAO1 by Microbial Proteomics. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1140:515-529. [DOI: 10.1007/978-3-030-15950-4_30] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
|
45
|
Rogers SO. Integrated evolution of ribosomal RNAs, introns, and intron nurseries. Genetica 2018; 147:103-119. [PMID: 30578455 DOI: 10.1007/s10709-018-0050-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2018] [Accepted: 12/13/2018] [Indexed: 12/21/2022]
Abstract
The initial components of ribosomes first appeared more than 3.8 billion years ago during a time when many types of RNAs were evolving. While modern ribosomes are complex molecular machines consisting of rRNAs and proteins, they were assembled during early evolution by the association and joining of small functional RNA units. Introns may have provided the means to ligate many of these pieces together. All four classes of introns (group I, group II, spliceosomal, and archaeal) are present in many rRNA gene loci over a broad phylogenetic range. A survey of rRNA intron sequences across the three major life domains suggests that some of the classes of introns may have diverged from one another within rRNA gene loci. Analyses of rRNA sequences revealed self-splicing group I and group II introns are present in ancestral regions of the SSU (small subunit) and LSU (large subunit), whereas spliceosomal and archaeal introns appeared in sections of the rRNA that evolved later. Most classes of introns increased in number for approximately 1 billion years. However, their frequencies are low in the most recently evolved regions added to the SSU and LSU rRNAs. Furthermore, many of the introns appear to have been in the same locations for billions of years, suggesting an ancient origin for these sequences. In this Perspectives paper, I reviewed and analyzed rRNA intron sequences, locations, structural characteristics, and splicing mechanisms; and suggest that rRNA gene loci may have served as evolutionary nurseries for intron formation and diversification.
Collapse
Affiliation(s)
- Scott O Rogers
- Department of Biological Sciences, Bowling Green State University, Bowling Green, OH, 43403, USA.
| |
Collapse
|
46
|
Zubaer A, Wai A, Hausner G. The mitochondrial genome of Endoconidiophora resinifera is intron rich. Sci Rep 2018; 8:17591. [PMID: 30514960 PMCID: PMC6279837 DOI: 10.1038/s41598-018-35926-y] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Accepted: 11/08/2018] [Indexed: 02/07/2023] Open
Abstract
Endoconidiophora resinifera (=Ceratocystis resinifera) is a blue-stain fungus that occurs on conifers. The data showed that the Endoconidiophora resinifera mitochondrial genome is one of the largest mitochondrial genomes (>220 kb) so far reported among members of the Ascomycota. An exceptional large number of introns (81) were noted and differences among the four strains were restricted to minor variations in intron numbers and a few indels and single nucleotide polymorphisms. The major differences among the four strains examined are due to size polymorphisms generated by the absence or presence of mitochondrial introns. Also, these mitochondrial genomes encode the largest cytochrome oxidase subunit 1 gene (47.5 kb) reported so far among the fungi. The large size for this gene again can be attributed to the large number of intron insertions. This study reports the first mitochondrial genome for the genus Endoconidiophora, previously members of this genus were assigned to Ceratocystis. The latter genus has recently undergone extensive taxonomic revisions and the mitochondrial genome might provide loci that could be applied as molecular markers assisting in the identification of taxa within this group of economically important fungi. The large mitochondrial genome also may provide some insight on mechanisms that can lead to mitochondrial genome expansion.
Collapse
Affiliation(s)
- Abdullah Zubaer
- Department of Microbiology, University of Manitoba, Winnipeg, MB, R3T 2N2, Canada
| | - Alvan Wai
- Department of Microbiology, University of Manitoba, Winnipeg, MB, R3T 2N2, Canada
| | - Georg Hausner
- Department of Microbiology, University of Manitoba, Winnipeg, MB, R3T 2N2, Canada.
| |
Collapse
|
47
|
Mendoza-Figueroa MS, Alfonso-Maqueira EE, Vélez C, Azuara-Liceaga EI, Zárate S, Villegas-Sepúlveda N, Saucedo-Cárdenas O, Valdés J. Postsplicing-Derived Full-Length Intron Circles in the Protozoan Parasite Entamoeba histolytica. Front Cell Infect Microbiol 2018; 8:255. [PMID: 30123775 PMCID: PMC6085484 DOI: 10.3389/fcimb.2018.00255] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Accepted: 07/04/2018] [Indexed: 12/13/2022] Open
Abstract
Noncoding circular RNAs are widespread in the tree of life. Particularly, intron-containing circular RNAs which apparently upregulate their parental gene expression. Entamoeba histolytica, the causative agent of dysentery and liver abscesses in humans, codes for several noncoding RNAs, including circular ribosomal RNAs, but no intron containing circular RNAs have been described to date. Divergent RT-PCR and diverse molecular approaches, allowed us to detect bona fide full-length intronic circular RNA (flicRNA) molecules. Self-splicing reactions, RNA polymerase II inhibition with Actinomycin D, and second step of splicing-inhibition with boric acid showed that the production of flicRX13 (one of the flicRNAs found in this work, and our test model) depends on mRNA synthesis and pre-mRNA processing instead of self-splicing. To explore the cues and factors involved in flicRX13 biogenesis in vivo, splicing assays were carried out in amoeba transformants where splicing factors and Dbr1 (intron lariat debranching enzyme 1) were silenced or overexpressed, or where Rabx13 wild-type and mutant 5'ss (splice site) and branch site minigene constructs were overexpressed. Whereas SF1 (splicing factor 1) is not involved, the U2 auxiliary splicing factor, Dbr1, and the GU-rich 5'ss are involved in postsplicing flicRX13 biogenesis, probably by Dbr1 stalling, in a similar fashion to the formation of ciRNAs (circular intronic RNAs), but with distinctive 5'-3'ss ligation points. Different from the reported functions of ciRNAs, the 5'ss GU-rich element of flicRX13 possibly interacts with transcription machinery to silence its own gene in cis. Furthermore, introns of E. histolytica virulence-related genes are also processed as flicRNAs.
Collapse
Affiliation(s)
- María S Mendoza-Figueroa
- Departamento de Bioquímica, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City, Mexico
| | - Eddy E Alfonso-Maqueira
- Departamento de Bioquímica, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City, Mexico
| | - Cristina Vélez
- Departamento de Biología Celular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City, Mexico
| | - Elisa I Azuara-Liceaga
- Posgrado en Ciencias Genómicas, Universidad Autónoma de la Ciudad de Mexico, Mexico City, Mexico
| | - Selene Zárate
- Posgrado en Ciencias Genómicas, Universidad Autónoma de la Ciudad de Mexico, Mexico City, Mexico
| | - Nicolás Villegas-Sepúlveda
- Departamento de Biomedicina Molecular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City, Mexico
| | - Odila Saucedo-Cárdenas
- Departamento de Histología, Facultad de Medicina, Universidad Autónoma de Nuevo León, Monterrey, Mexico.,División de Genética, Centro de Investigación Biomédica del Noreste, Instituto Mexicano del Seguro Social, Monterrey, Mexico
| | - Jesús Valdés
- Departamento de Bioquímica, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City, Mexico
| |
Collapse
|
48
|
Suess B, Kemmerer K, Weigand JE. Splicing and Alternative Splicing Impact on Gene Design. Synth Biol (Oxf) 2018. [DOI: 10.1002/9783527688104.ch7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Affiliation(s)
- Beatrix Suess
- Department of Biology; Technische Universität Darmstadt; Schnittspahnstraße 10 64287 Darmstadt Germany
| | - Katrin Kemmerer
- Department of Biology; Technische Universität Darmstadt; Schnittspahnstraße 10 64287 Darmstadt Germany
| | - Julia E. Weigand
- Department of Biology; Technische Universität Darmstadt; Schnittspahnstraße 10 64287 Darmstadt Germany
| |
Collapse
|
49
|
Gomes FEES, Arantes TD, Fernandes JAL, Ferreira LC, Romero H, Bosco SMG, Oliveira MTB, Del Negro GMB, Theodoro RC. Polymorphism in Mitochondrial Group I Introns among Cryptococcus neoformans and Cryptococcus gattii Genotypes and Its Association with Drug Susceptibility. Front Microbiol 2018; 9:86. [PMID: 29467729 PMCID: PMC5808193 DOI: 10.3389/fmicb.2018.00086] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Accepted: 01/12/2018] [Indexed: 12/21/2022] Open
Abstract
Cryptococcosis, one of the most important systemic mycosis in the world, is caused by different genotypes of Cryptococcus neoformans and Cryptococcus gattii, which differ in their ecology, epidemiology, and antifungal susceptibility. Therefore, the search for new molecular markers for genotyping, pathogenicity and drug susceptibility is necessary. Group I introns fulfill the requisites for such task because (i) they are polymorphic sequences; (ii) their self-splicing is inhibited by some drugs; and (iii) their correct splicing under parasitic conditions is indispensable for pathogen survival. Here, we investigated the presence of group I introns in the mitochondrial LSU rRNA gene in 77 Cryptococcus isolates and its possible relation to drug susceptibility. Sequencing revealed two new introns in the LSU rRNA gene. All the introns showed high sequence similarity to other mitochondrial introns from distinct fungi, supporting the hypothesis of an ancient non-allelic invasion. Intron presence was statistically associated with those genotypes reported to be less pathogenic (p < 0.001). Further virulence assays are needed to confirm this finding. In addition, in vitro antifungal tests indicated that the presence of LSU rRNA introns may influence the minimum inhibitory concentration (MIC) of amphotericin B and 5-fluorocytosine. These findings point to group I introns in the mitochondrial genome of Cryptococcus as potential molecular markers for antifungal resistance, as well as therapeutic targets.
Collapse
Affiliation(s)
- Felipe E. E. S. Gomes
- Department of Biochemistry, Universidade Federal do Rio Grande do Norte, Natal, Brazil
- Institute of Tropical Medicine of Rio Grande do Norte, Universidade Federal do Rio Grande do Norte, Natal, Brazil
| | - Thales D. Arantes
- Department of Biochemistry, Universidade Federal do Rio Grande do Norte, Natal, Brazil
- Institute of Tropical Medicine of Rio Grande do Norte, Universidade Federal do Rio Grande do Norte, Natal, Brazil
| | - José A. L. Fernandes
- Institute of Tropical Medicine of Rio Grande do Norte, Universidade Federal do Rio Grande do Norte, Natal, Brazil
| | - Leonardo C. Ferreira
- Department of Biochemistry, Universidade Federal do Rio Grande do Norte, Natal, Brazil
- Institute of Tropical Medicine of Rio Grande do Norte, Universidade Federal do Rio Grande do Norte, Natal, Brazil
| | - Héctor Romero
- Laboratorio de Organizacion y Evolución del Genoma/Unidad de Genómica Evolutiva, Departamento de Ecología y Evolución, Facultad de Ciencias/CURE, Universidad de la República, Maldonado, Uruguay
| | - Sandra M. G. Bosco
- Department of Microbiology and Immunology, Institute of Biosciences, Universidade Estadual Paulista Julio de Mesquita Filho, São Paulo, Brazil
| | - Maria T. B. Oliveira
- Department of Microbiology and Parasitology, Universidade Federal do Rio Grande do Norte, Natal, Brazil
| | - Gilda M. B. Del Negro
- Institute of Tropical Medicine of São Paulo, Universidade de São Paulo, São Paulo, Brazil
| | - Raquel C. Theodoro
- Institute of Tropical Medicine of Rio Grande do Norte, Universidade Federal do Rio Grande do Norte, Natal, Brazil
| |
Collapse
|
50
|
Isolation and characterization of a N4-like lytic bacteriophage infecting Vibrio splendidus, a pathogen of fish and bivalves. PLoS One 2017; 12:e0190083. [PMID: 29284014 PMCID: PMC5746245 DOI: 10.1371/journal.pone.0190083] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2017] [Accepted: 12/07/2017] [Indexed: 12/04/2022] Open
Abstract
A novel virulent bacteriophage, vB_VspP_pVa5, infecting a strain of Vibrio splendidus was isolated from a sea-cage aquaculture farm in Greece, and characterized using microbiological methods and genomic analysis. Bacteriophage vB_VspP_pVa5 is a N4-like podovirus with an icosahedral head measuring 85 nm in length and a short non-contractile tail. The phage had a narrow host range infecting only the bacterial host, a latent period of 30 min and a burst size of 24 virions per infected bacterium. Its genome size was 78,145 bp and genomic analysis identified 107 densely-packed genes, 40 of which could be annotated. In addition to the very large virion encapsulated DNA-dependent RNA polymerase which is the signature of the N4-like genus, an interesting feature of the novel phage is the presence of a self-splicing group I intron in the thymidylate synthase gene. A tRNAStop interrupted by a ~2.5kb open reading frame–containing area was also identified. The absence of genes related to lysogeny along with the high efficacy observed during in vitro cell lysis trials, indicate that the vB_VspP_pVa5 is a potential candidate component in a bacteriophage cocktail suitable for the biological control of V. splendidus in aquaculture.
Collapse
|