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Article ; Online: Recruitment of Mobile Genetic Elements for Diverse Cellular Functions in Prokaryotes

Sean Benler / Eugene V. Koonin

Frontiers in Molecular Biosciences, Vol

2022 Volume 9

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 ... ...

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.
Keywords	mobile genetic element ; exaptation ; antivirus defense mechanisms ; biological conflict systems ; horizontal gene transfer ; Biology (General) ; QH301-705.5
Subject code	572
Language	English
Publishing date	2022-03-01T00:00:00Z
Publisher	Frontiers Media S.A.
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Protocol for comparing gene-level selection on coding mutations between two groups of samples with Coselens

Jaime Iranzo / George Gruenhagen / Jorge Calle-Espinosa / Eugene V. Koonin

STAR Protocols, Vol 4, Iss 1, Pp 102117- (2023)

2023

Abstract: Summary: The study of genes that evolve under conditional selection can shed light on the genomic underpinnings of adaptation, revealing epistasis and phenotypic plasticity. This protocol describes how to use the Coselens package to compare gene-level ... ...

Abstract	Summary: The study of genes that evolve under conditional selection can shed light on the genomic underpinnings of adaptation, revealing epistasis and phenotypic plasticity. This protocol describes how to use the Coselens package to compare gene-level selection between two groups of samples. After installing Coselens and preparing the datasets, a typical run on a laptop takes less than 10 min. Coselens is best suited to analyze somatic mutations and data from experimental evolution, for which independently evolved samples are available.For complete details on the use and execution of this protocol, please refer to Iranzo et al. (2022).1 : Publisher’s note: Undertaking any experimental protocol requires adherence to local institutional guidelines for laboratory safety and ethics.
Keywords	Bioinformatics ; Cancer ; Evolutionary biology ; Genomics ; Science (General) ; Q1-390
Language	English
Publishing date	2023-03-01T00:00:00Z
Publisher	Elsevier
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Plant virus movement proteins originated from jelly-roll capsid proteins.

Anamarija Butkovic / Valerian V Dolja / Eugene V Koonin / Mart Krupovic

PLoS Biology, Vol 21, Iss 6, p e

2023 Volume 3002157

Abstract: Numerous, diverse plant viruses encode movement proteins (MPs) that aid the virus movement through plasmodesmata, the plant intercellular channels. MPs are essential for virus spread and propagation in distal tissues, and several unrelated MPs have been ... ...

Abstract	Numerous, diverse plant viruses encode movement proteins (MPs) that aid the virus movement through plasmodesmata, the plant intercellular channels. MPs are essential for virus spread and propagation in distal tissues, and several unrelated MPs have been identified. The 30K superfamily of MPs (named after the molecular mass of tobacco mosaic virus MP, the classical model of plant virology) is the largest and most diverse MP variety, represented in 16 virus families, but its evolutionary origin remained obscure. Here, we show that the core structural domain of the 30K MPs is homologous to the jelly-roll domain of the capsid proteins (CPs) of small RNA and DNA viruses, in particular, those infecting plants. The closest similarity was observed between the 30K MPs and the CPs of the viruses in the families Bromoviridae and Geminiviridae. We hypothesize that the MPs evolved via duplication or horizontal acquisition of the CP gene in a virus that infected an ancestor of vascular plants, followed by neofunctionalization of one of the paralogous CPs, potentially through the acquisition of unique N- and C-terminal regions. During the subsequent coevolution of viruses with diversifying vascular plants, the 30K MP genes underwent explosive horizontal spread among emergent RNA and DNA viruses, likely permitting viruses of insects and fungi that coinfected plants to expand their host ranges, molding the contemporary plant virome.
Keywords	Biology (General) ; QH301-705.5
Subject code	580
Language	English
Publishing date	2023-06-01T00:00:00Z
Publisher	Public Library of Science (PLoS)
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Evolutionary plasticity and functional versatility of CRISPR systems.

Eugene V Koonin / Kira S Makarova

PLoS Biology, Vol 20, Iss 1, p e

2022 Volume 3001481

Abstract: The principal biological function of bacterial and archaeal CRISPR systems is RNA-guided adaptive immunity against viruses and other mobile genetic elements (MGEs). These systems show remarkable evolutionary plasticity and functional versatility at ... ...

Abstract	The principal biological function of bacterial and archaeal CRISPR systems is RNA-guided adaptive immunity against viruses and other mobile genetic elements (MGEs). These systems show remarkable evolutionary plasticity and functional versatility at multiple levels, including both the defense mechanisms that lead to direct, specific elimination of the target DNA or RNA and those that cause programmed cell death (PCD) or induction of dormancy. This flexibility is also evident in the recruitment of CRISPR systems for nondefense functions. Defective CRISPR systems or individual CRISPR components have been recruited by transposons for RNA-guided transposition, by plasmids for interplasmid competition, and by viruses for antidefense and interviral conflicts. Additionally, multiple highly derived CRISPR variants of yet unknown functions have been discovered. A major route of innovation in CRISPR evolution is the repurposing of diverged repeat variants encoded outside CRISPR arrays for various structural and regulatory functions. The evolutionary plasticity and functional versatility of CRISPR systems are striking manifestations of the ubiquitous interplay between defense and "normal" cellular functions.
Keywords	Biology (General) ; QH301-705.5
Subject code	572
Language	English
Publishing date	2022-01-01T00:00:00Z
Publisher	Public Library of Science (PLoS)
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Is Protein Folding a Thermodynamically Unfavorable, Active, Energy-Dependent Process?

Irina Sorokina / Arcady R. Mushegian / Eugene V. Koonin

International Journal of Molecular Sciences, Vol 23, Iss 521, p

2022 Volume 521

Abstract: The prevailing current view of protein folding is the thermodynamic hypothesis, under which the native folded conformation of a protein corresponds to the global minimum of Gibbs free energy G . We question this concept and show that the empirical ... ...

Abstract	The prevailing current view of protein folding is the thermodynamic hypothesis, under which the native folded conformation of a protein corresponds to the global minimum of Gibbs free energy G . We question this concept and show that the empirical evidence behind the thermodynamic hypothesis of folding is far from strong. Furthermore, physical theory-based approaches to the prediction of protein folds and their folding pathways so far have invariably failed except for some very small proteins, despite decades of intensive theory development and the enormous increase of computer power. The recent spectacular successes in protein structure prediction owe to evolutionary modeling of amino acid sequence substitutions enhanced by deep learning methods, but even these breakthroughs provide no information on the protein folding mechanisms and pathways. We discuss an alternative view of protein folding, under which the native state of most proteins does not occupy the global free energy minimum, but rather, a local minimum on a fluctuating free energy landscape. We further argue that Δ G of folding is likely to be positive for the majority of proteins, which therefore fold into their native conformations only through interactions with the energy-dependent molecular machinery of living cells, in particular, the translation system and chaperones. Accordingly, protein folding should be modeled as it occurs in vivo, that is, as a non-equilibrium, active, energy-dependent process.
Keywords	protein folding ; entropy ; free energy ; free energy landscape ; energy-dependent protein folding ; co-translational protein folding ; Biology (General) ; QH301-705.5 ; Chemistry ; QD1-999
Subject code	612
Language	English
Publishing date	2022-01-01T00:00:00Z
Publisher	MDPI AG
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Evolutionary plasticity and functional versatility of CRISPR systems

Eugene V. Koonin / Kira S. Makarova

PLoS Biology, Vol 20, Iss

2022 Volume 1

Abstract	The principal biological function of bacterial and archaeal CRISPR systems is RNA-guided adaptive immunity against viruses and other mobile genetic elements (MGEs). These systems show remarkable evolutionary plasticity and functional versatility at multiple levels, including both the defense mechanisms that lead to direct, specific elimination of the target DNA or RNA and those that cause programmed cell death (PCD) or induction of dormancy. This flexibility is also evident in the recruitment of CRISPR systems for nondefense functions. Defective CRISPR systems or individual CRISPR components have been recruited by transposons for RNA-guided transposition, by plasmids for interplasmid competition, and by viruses for antidefense and interviral conflicts. Additionally, multiple highly derived CRISPR variants of yet unknown functions have been discovered. A major route of innovation in CRISPR evolution is the repurposing of diverged repeat variants encoded outside CRISPR arrays for various structural and regulatory functions. The evolutionary plasticity and functional versatility of CRISPR systems are striking manifestations of the ubiquitous interplay between defense and “normal” cellular functions. The CRISPR systems show remarkable functional versatility beyond their principal function as an adaptive immune mechanism. This Essay discusses how derived CRISPR systems have been recruited by transposons on multiple occasions and mediate RNA-guided transposition; derived CRISPR RNAs are frequently recruited for regulatory functions.
Keywords	Biology (General) ; QH301-705.5
Language	English
Publishing date	2022-01-01T00:00:00Z
Publisher	Public Library of Science (PLoS)
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Viroids and Viroid-like Circular RNAs

Benjamin D. Lee / Eugene V. Koonin

Life, Vol 12, Iss 103, p

Do They Descend from Primordial Replicators?

2022 Volume 103

Abstract: Viroids are a unique class of plant pathogens that consist of small circular RNA molecules, between 220 and 450 nucleotides in size. Viroids encode no proteins and are the smallest known infectious agents. Viroids replicate via the rolling circle ... ...

Abstract	Viroids are a unique class of plant pathogens that consist of small circular RNA molecules, between 220 and 450 nucleotides in size. Viroids encode no proteins and are the smallest known infectious agents. Viroids replicate via the rolling circle mechanism, producing multimeric intermediates which are cleaved to unit length either by ribozymes formed from both polarities of the viroid genomic RNA or by coopted host RNAses. Many viroid-like small circular RNAs are satellites of plant RNA viruses. Ribozyviruses, represented by human hepatitis delta virus, are larger viroid-like circular RNAs that additionally encode the viral nucleocapsid protein. It has been proposed that viroids are direct descendants of primordial RNA replicons that were present in the hypothetical RNA world. We argue, however, that much later origin of viroids, possibly, from recently discovered mobile genetic elements known as retrozymes, is a far more parsimonious evolutionary scenario. Nevertheless, viroids and viroid-like circular RNAs are minimal replicators that are likely to be close to the theoretical lower limit of replicator size and arguably comprise the paradigm for replicator emergence. Thus, although viroid-like replicators are unlikely to be direct descendants of primordial RNA replicators, the study of the diversity and evolution of these ultimate genetic parasites can yield insights into the earliest stages of the evolution of life.
Keywords	viroids ; ribozyviruses ; primordial replicators ; ribozymes ; origin of life ; Science ; Q
Language	English
Publishing date	2022-01-01T00:00:00Z
Publisher	MDPI AG
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Open questions

Eugene V. Koonin

BMC Biology, Vol 16, Iss 1, Pp 1-

CRISPR biology

2018 Volume 3

Abstract: Abstract CRISPR-Cas systems, the purveyors of adaptive immunity in archaea and bacteria and sources of the new generation of genome engineering tools, have been studied in exquisite molecular detail. However, when it comes to biological functions, ... ...

Abstract	Abstract CRISPR-Cas systems, the purveyors of adaptive immunity in archaea and bacteria and sources of the new generation of genome engineering tools, have been studied in exquisite molecular detail. However, when it comes to biological functions, ecology, and evolution of CRISPR-Cas, many more intriguing questions remain than there are answers.
Keywords	Biology (General) ; QH301-705.5
Language	English
Publishing date	2018-09-01T00:00:00Z
Publisher	BMC
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Incorporating Machine Learning into Established Bioinformatics Frameworks

Noam Auslander / Ayal B. Gussow / Eugene V. Koonin

International Journal of Molecular Sciences, Vol 22, Iss 2903, p

2021 Volume 2903

Abstract: The exponential growth of biomedical data in recent years has urged the application of numerous machine learning techniques to address emerging problems in biology and clinical research. By enabling the automatic feature extraction, selection, and ... ...

Abstract	The exponential growth of biomedical data in recent years has urged the application of numerous machine learning techniques to address emerging problems in biology and clinical research. By enabling the automatic feature extraction, selection, and generation of predictive models, these methods can be used to efficiently study complex biological systems. Machine learning techniques are frequently integrated with bioinformatic methods, as well as curated databases and biological networks, to enhance training and validation, identify the best interpretable features, and enable feature and model investigation. Here, we review recently developed methods that incorporate machine learning within the same framework with techniques from molecular evolution, protein structure analysis, systems biology, and disease genomics. We outline the challenges posed for machine learning, and, in particular, deep learning in biomedicine, and suggest unique opportunities for machine learning techniques integrated with established bioinformatics approaches to overcome some of these challenges.
Keywords	machine learning ; deep learning ; bioinformatics methods ; phylogenetics ; Biology (General) ; QH301-705.5 ; Chemistry ; QD1-999
Subject code	006
Language	English
Publishing date	2021-03-01T00:00:00Z
Publisher	MDPI AG
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Assessment of assumptions underlying models of prokaryotic pangenome evolution

Itamar Sela / Yuri I. Wolf / Eugene V. Koonin

BMC Biology, Vol 19, Iss 1, Pp 1-

2021 Volume 15

Abstract: Abstract Background The genomes of bacteria and archaea evolve by extensive loss and gain of genes which, for any group of related prokaryotic genomes, result in the formation of a pangenome with the universal, asymmetrical U-shaped distribution of gene ... ...

Abstract	Abstract Background The genomes of bacteria and archaea evolve by extensive loss and gain of genes which, for any group of related prokaryotic genomes, result in the formation of a pangenome with the universal, asymmetrical U-shaped distribution of gene commonality. However, the evolutionary factors that define the specific shape of this distribution are not thoroughly understood. Results We investigate the fit of simple models of genome evolution to the empirically observed gene commonality distributions and genome intersections for 33 groups of closely related bacterial genomes. A model with an infinite external gene pool available for gene acquisition and constant genome size (IGP-CGS model), and two gene turnover rates, one for slow- and the other one for fast-evolving genes, allows two approaches to estimate the parameters for gene content dynamics. One is by fitting the model prediction to the distribution of the number of genes shared by precisely k genomes (gene commonality distribution) and another by analyzing the distribution of the number of genes common for k genome sets (k-cores). Both approaches produce a comparable overall quality of fit, although the former significantly overestimates the number of the universally conserved genes, while the latter overestimates the number of singletons. We further explore the effect of dropping each of the assumptions of the IGP-CGS model on the fit to the gene commonality distributions and show that models with either a finite gene pool or unequal rates of gene loss and gain (greater gene loss rate) eliminate the overestimate of the number of singletons or the core genome size. Conclusions We examine the assumptions that are usually adopted for modeling the evolution of the U-shaped gene commonality distributions in prokaryote genomes, namely, those of infinitely many genes and constant genome size. The combined analysis of genome intersections and gene commonality suggests that at least one of these assumptions is invalid. The violation of both these ...
Keywords	Evolutionary genomics ; Bacterial evolution ; Pangenome ; Quantitative biology ; Biology (General) ; QH301-705.5
Subject code	612
Language	English
Publishing date	2021-02-01T00:00:00Z
Publisher	BMC
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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