CACTA transposable elements (TEs) comprise one of the most abundant superfamilies of Class 2 (cut-and-paste) transposons. Over recent decades, CACTA elements were widely identified in species from the plant, fungi, and animal kingdoms, but sufficiently studied in the genomes of only a few model species although non-model genomes can bring additional and valuable information. It primarily concerned the genomes of species belonging to clades in the base of large taxonomic groups whose genomes, to a certain extent, can preserve relict and/or possesses specific traits. Thus, we sought to investigate the genomes of Chenopodium (Amaranthaceae, Caryophyllales) species to unravel the structural variability of CACTA elements. Caryophyllales is a separate branch of Angiosperms and until recently the diversity of CACTA elements in this clade was unknown. Application of the short-read genome assembly algorithm followed by analysis of detected complete CACTA elements allowed for the determination of their structural diversity in the genomes of 22 Chenopodium album aggregate species. This approach yielded knowledge regarding: (i) the coexistence of two CACTA transposons subtypes in single genome; (ii) gaining of additional protein conserved domains within the coding sequence; (iii) the presence of captured gene fragments, including key genes for flower development; and (iv)) identification of captured satDNA arrays. Wide comparative database analysis revealed that identified events are scattered through Angiosperms in different proportions. Our study demonstrated that while preserving the basic element structure a wide range of coding and non-coding additions to CACTA transposons occur in the genomes of C. album aggregate species. Ability to relocate additions inside genome in combination with the proposed novel functional features of structural-different CACTA elements can impact evolutionary trajectory of the host genome.
CACTA转座子(TEs)是一类最丰富的2类(剪切-粘贴)转座子超家族之一。近几十年来,CACTA元件在植物、真菌和动物领域的物种中得到了广泛的鉴定,但在少数模式物种的基因组中得到了充分的研究,尽管非模式基因组可以带来额外的有价值的信息。它主要涉及属于大型分类群基础分支的物种的基因组,这些物种的基因组在一定程度上可以保存遗存和/或具有特定特征。因此,我们对藜属植物(苋菜科,石竹科)的基因组进行了研究,以揭示CACTA元件的结构变异性。石竹属植物是被子植物的一个独立分支,直到最近才知道这个分支中CACTA元素的多样性。应用短读基因组组装算法,对检测到的完整CACTA元件进行分析,确定了22种Chenopodium album aggregate种基因组的结构多样性。该方法获得了以下方面的知识:(i)两个CACTA转座子亚型在单个基因组中共存;(ii)在编码序列中获得额外的蛋白质保守结构域;(iii)存在捕获的基因片段,包括花发育的关键基因;(iv)识别捕获的卫星dna阵列。。广泛的比较数据库分析显示,确定的事件以不同的比例分散在被子植物中。我们的研究表明,在保留基本元件结构的同时,CACTA转座子出现了广泛的编码和非编码添加。基因组内添加物的重新定位能力与CACTA元件结构不同的新功能特征相结合,可以影响宿主基因组的进化轨迹。
{"title":"The structural diversity of CACTA transposons in genomes of Chenopodium (Amaranthaceae, Caryophyllales) species: specific traits and comparison with the similar elements of angiosperms","authors":"Belyayev, Alexander, Josefiová, Jiřina, Jandová, Michaela, Kalendar, Ruslan, Mahelka, Václav, Mandák, Bohumil, Krak, Karol","doi":"10.1186/s13100-022-00265-3","DOIUrl":"https://doi.org/10.1186/s13100-022-00265-3","url":null,"abstract":"CACTA transposable elements (TEs) comprise one of the most abundant superfamilies of Class 2 (cut-and-paste) transposons. Over recent decades, CACTA elements were widely identified in species from the plant, fungi, and animal kingdoms, but sufficiently studied in the genomes of only a few model species although non-model genomes can bring additional and valuable information. It primarily concerned the genomes of species belonging to clades in the base of large taxonomic groups whose genomes, to a certain extent, can preserve relict and/or possesses specific traits. Thus, we sought to investigate the genomes of Chenopodium (Amaranthaceae, Caryophyllales) species to unravel the structural variability of CACTA elements. Caryophyllales is a separate branch of Angiosperms and until recently the diversity of CACTA elements in this clade was unknown. Application of the short-read genome assembly algorithm followed by analysis of detected complete CACTA elements allowed for the determination of their structural diversity in the genomes of 22 Chenopodium album aggregate species. This approach yielded knowledge regarding: (i) the coexistence of two CACTA transposons subtypes in single genome; (ii) gaining of additional protein conserved domains within the coding sequence; (iii) the presence of captured gene fragments, including key genes for flower development; and (iv)) identification of captured satDNA arrays. Wide comparative database analysis revealed that identified events are scattered through Angiosperms in different proportions. Our study demonstrated that while preserving the basic element structure a wide range of coding and non-coding additions to CACTA transposons occur in the genomes of C. album aggregate species. Ability to relocate additions inside genome in combination with the proposed novel functional features of structural-different CACTA elements can impact evolutionary trajectory of the host genome.","PeriodicalId":18854,"journal":{"name":"Mobile DNA","volume":"177 1","pages":""},"PeriodicalIF":4.9,"publicationDate":"2022-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138518123","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-03-30DOI: 10.1186/s13100-021-00259-7
Goubert, Clement, Craig, Rory J., Bilat, Agustin F., Peona, Valentina, Vogan, Aaron A., Protasio, Anna V.
In the study of transposable elements (TEs), the generation of a high confidence set of consensus sequences that represent the diversity of TEs found in a given genome is a key step in the path to investigate these fascinating genomic elements. Many algorithms and pipelines are available to automatically identify putative TE families present in a genome. Despite the availability of these valuable resources, producing a library of high-quality full-length TE consensus sequences largely remains a process of manual curation. This know-how is often passed on from mentor-to-mentee within research groups, making it difficult for those outside the field to access this highly specialised skill. Our manuscript attempts to fill this gap by providing a set of detailed computer protocols, software recommendations and video tutorials for those aiming to manually curate TEs. Detailed step-by-step protocols, aimed at the complete beginner, are presented in the Supplementary Methods. The proposed set of programs and tools presented here will make the process of manual curation achievable and amenable to all researchers and in special to those new to the field of TEs.
{"title":"A beginner’s guide to manual curation of transposable elements","authors":"Goubert, Clement, Craig, Rory J., Bilat, Agustin F., Peona, Valentina, Vogan, Aaron A., Protasio, Anna V.","doi":"10.1186/s13100-021-00259-7","DOIUrl":"https://doi.org/10.1186/s13100-021-00259-7","url":null,"abstract":"In the study of transposable elements (TEs), the generation of a high confidence set of consensus sequences that represent the diversity of TEs found in a given genome is a key step in the path to investigate these fascinating genomic elements. Many algorithms and pipelines are available to automatically identify putative TE families present in a genome. Despite the availability of these valuable resources, producing a library of high-quality full-length TE consensus sequences largely remains a process of manual curation. This know-how is often passed on from mentor-to-mentee within research groups, making it difficult for those outside the field to access this highly specialised skill. Our manuscript attempts to fill this gap by providing a set of detailed computer protocols, software recommendations and video tutorials for those aiming to manually curate TEs. Detailed step-by-step protocols, aimed at the complete beginner, are presented in the Supplementary Methods. The proposed set of programs and tools presented here will make the process of manual curation achievable and amenable to all researchers and in special to those new to the field of TEs.","PeriodicalId":18854,"journal":{"name":"Mobile DNA","volume":"14 1","pages":""},"PeriodicalIF":4.9,"publicationDate":"2022-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138518131","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-02-02DOI: 10.21203/rs.3.rs-1312818/v1
Juan Paolo A. Sicat, Paul Visendi, Steven O. Sewe, S. Bouvaine, S. Seal
Background Whiteflies are agricultural pests that have caused worldwide negative impacts that have led to severe financial losses. The Bemisia tabaci whitefly species complex is the most damaging in terms of their broad crop host range and its ability to serve as vector for over 300 plant viruses. Whitefly genomes of the species complex provide valuable genomic data; however, transposable elements (TEs) within the species complex remain unexplored. This study provides the first accurate exploration of TE content within the B. tabaci species complex.Results This study identified an average of 40.61% of the genomes of three whitefly species (MEAM1, MEDQ, and SSA-ECA) consists of TEs. Majority of the TEs identified were DNA transposons (22.85% average) while SINEs (0.14% average) were the least represented. This study also compared the TE content the three whitefly genomes with three other hemipteran genomes and found a significant difference in the presence of DNA transposons and LINEs. A total of 63 TE superfamilies were identified to be present across the three whitefly species (39 DNA transposons, six LTR, 16 LINE, and two SINE) of which 11 TE superfamilies were identified to not be present in the three other hemipteran genomes (nine DNA transposon, and two LINE). This study is the first to characterize TEs found within different B. tabaci species and has created a standardized annotation workflow that could be used to analyze future whitefly genomes.Conclusion This study is the first to characterize the landscape of TEs within the B. tabaci species complex. The characterization of these elements within the three whitefly genomes shows that TEs occupy a significant portion of the whitefly genome, majority of which are DNA transposons. This study also identified TE superfamilies of note and provides a framework for future TE studies within the species complex.
{"title":"Correction: Characterization of transposable elements within the Bemisia tabaci species complex","authors":"Juan Paolo A. Sicat, Paul Visendi, Steven O. Sewe, S. Bouvaine, S. Seal","doi":"10.21203/rs.3.rs-1312818/v1","DOIUrl":"https://doi.org/10.21203/rs.3.rs-1312818/v1","url":null,"abstract":"\u0000 Background Whiteflies are agricultural pests that have caused worldwide negative impacts that have led to severe financial losses. The Bemisia tabaci whitefly species complex is the most damaging in terms of their broad crop host range and its ability to serve as vector for over 300 plant viruses. Whitefly genomes of the species complex provide valuable genomic data; however, transposable elements (TEs) within the species complex remain unexplored. This study provides the first accurate exploration of TE content within the B. tabaci species complex.Results This study identified an average of 40.61% of the genomes of three whitefly species (MEAM1, MEDQ, and SSA-ECA) consists of TEs. Majority of the TEs identified were DNA transposons (22.85% average) while SINEs (0.14% average) were the least represented. This study also compared the TE content the three whitefly genomes with three other hemipteran genomes and found a significant difference in the presence of DNA transposons and LINEs. A total of 63 TE superfamilies were identified to be present across the three whitefly species (39 DNA transposons, six LTR, 16 LINE, and two SINE) of which 11 TE superfamilies were identified to not be present in the three other hemipteran genomes (nine DNA transposon, and two LINE). This study is the first to characterize TEs found within different B. tabaci species and has created a standardized annotation workflow that could be used to analyze future whitefly genomes.Conclusion This study is the first to characterize the landscape of TEs within the B. tabaci species complex. The characterization of these elements within the three whitefly genomes shows that TEs occupy a significant portion of the whitefly genome, majority of which are DNA transposons. This study also identified TE superfamilies of note and provides a framework for future TE studies within the species complex.","PeriodicalId":18854,"journal":{"name":"Mobile DNA","volume":" ","pages":""},"PeriodicalIF":4.9,"publicationDate":"2022-02-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42717241","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-01-18DOI: 10.1186/s13100-021-00260-0
Alexandra Iouranova, Delphine Grun, Tamara Rossy, Julien Duc, Alexandre Coudray, Michael Imbeault, Jonas de Tribolet-Hardy, Priscilla Turelli, Alexandre Persat, Didier Trono
Background: Transposable element-embedded regulatory sequences (TEeRS) and their KRAB-containing zinc finger protein (KZFP) controllers are increasingly recognized as modulators of gene expression. We aim to characterize the contribution of this system to gene regulation in early human development and germ cells.
Results: Here, after studying genes driven by the long terminal repeat (LTR) of endogenous retroviruses, we identify the ape-restricted ZNF676 as the sequence-specific repressor of a subset of contemporary LTR12 integrants responsible for a large fraction of transpochimeric gene transcripts (TcGTs) generated during human early embryogenesis. We go on to reveal that the binding of this KZFP correlates with the epigenetic marking of these TEeRS in the germline, and is crucial to the control of genes involved in ciliogenesis/flagellogenesis, a biological process that dates back to the last common ancestor of eukaryotes.
Conclusion: These results illustrate how KZFPs and their TE targets contribute to the evolutionary turnover of transcription networks and participate in the transgenerational inheritance of epigenetic traits.
{"title":"KRAB zinc finger protein ZNF676 controls the transcriptional influence of LTR12-related endogenous retrovirus sequences.","authors":"Alexandra Iouranova, Delphine Grun, Tamara Rossy, Julien Duc, Alexandre Coudray, Michael Imbeault, Jonas de Tribolet-Hardy, Priscilla Turelli, Alexandre Persat, Didier Trono","doi":"10.1186/s13100-021-00260-0","DOIUrl":"10.1186/s13100-021-00260-0","url":null,"abstract":"<p><strong>Background: </strong>Transposable element-embedded regulatory sequences (TEeRS) and their KRAB-containing zinc finger protein (KZFP) controllers are increasingly recognized as modulators of gene expression. We aim to characterize the contribution of this system to gene regulation in early human development and germ cells.</p><p><strong>Results: </strong>Here, after studying genes driven by the long terminal repeat (LTR) of endogenous retroviruses, we identify the ape-restricted ZNF676 as the sequence-specific repressor of a subset of contemporary LTR12 integrants responsible for a large fraction of transpochimeric gene transcripts (TcGTs) generated during human early embryogenesis. We go on to reveal that the binding of this KZFP correlates with the epigenetic marking of these TEeRS in the germline, and is crucial to the control of genes involved in ciliogenesis/flagellogenesis, a biological process that dates back to the last common ancestor of eukaryotes.</p><p><strong>Conclusion: </strong>These results illustrate how KZFPs and their TE targets contribute to the evolutionary turnover of transcription networks and participate in the transgenerational inheritance of epigenetic traits.</p>","PeriodicalId":18854,"journal":{"name":"Mobile DNA","volume":"13 1","pages":"4"},"PeriodicalIF":4.9,"publicationDate":"2022-01-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8767690/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10263436","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Designing complex, dynamic yet multi-functional materials and devices is challenging because the design spaces for these materials have numerous interdependent and often conflicting constraints. Taking inspiration from advances in artificial intelligence and their applications in material discovery, we propose a computational method for designing metamorphic DNA-co-polymerized hydrogel structures. The method consists of a coarse-grained simulation and a deep learning-guided optimization system for exploring the immense design space of these structures. Here, we develop a simple numeric simulation of DNA-co-polymerized hydrogel shape change and seek to find designs for structured hydrogels that can fold into the shapes of different Arabic numerals in different actuation states. We train a convolutional neural network to classify and score the geometric outputs of the coarse-grained simulation to provide autonomous feedback for design optimization. We then construct a genetic algorithm that generates and selects large batches of material designs that compete with one another to evolve and converge on optimal objective-matching designs. We show that we are able to explore the large design space and learn important parameters and traits. We identify vital relationships between the material scale size and the range of shape change that can be achieved by individual domains and we elucidate trade-offs between different design parameters. Finally, we discover material designs capable of transforming into multiple different digits in different actuation states.
{"title":"Exploring Material Design Space with a Deep-Learning Guided Genetic Algorithm","authors":"Kuan-Lin Chen, Rebecca Schulman","doi":"10.4230/LIPIcs.DNA.28.4","DOIUrl":"https://doi.org/10.4230/LIPIcs.DNA.28.4","url":null,"abstract":"Designing complex, dynamic yet multi-functional materials and devices is challenging because the design spaces for these materials have numerous interdependent and often conflicting constraints. Taking inspiration from advances in artificial intelligence and their applications in material discovery, we propose a computational method for designing metamorphic DNA-co-polymerized hydrogel structures. The method consists of a coarse-grained simulation and a deep learning-guided optimization system for exploring the immense design space of these structures. Here, we develop a simple numeric simulation of DNA-co-polymerized hydrogel shape change and seek to find designs for structured hydrogels that can fold into the shapes of different Arabic numerals in different actuation states. We train a convolutional neural network to classify and score the geometric outputs of the coarse-grained simulation to provide autonomous feedback for design optimization. We then construct a genetic algorithm that generates and selects large batches of material designs that compete with one another to evolve and converge on optimal objective-matching designs. We show that we are able to explore the large design space and learn important parameters and traits. We identify vital relationships between the material scale size and the range of shape change that can be achieved by individual domains and we elucidate trade-offs between different design parameters. Finally, we discover material designs capable of transforming into multiple different digits in different actuation states.","PeriodicalId":18854,"journal":{"name":"Mobile DNA","volume":"42 1","pages":"4:1-4:14"},"PeriodicalIF":4.9,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80896202","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Bowen Li, N. Mackenzie, Ben Shirt-Ediss, N. Krasnogor, P. Zuliani
A DNA stack nano-device is a bio-computing system that can read and write molecular signals based on DNA-DNA hybridisation and strand displacement. In vitro implementation of the DNA stack faces a number of challenges affecting the performance of the system. In this work, we apply probabilistic model checking to analyse and optimise the DNA stack system. We develop a model framework based on continuous-time Markov chains to quantitatively describe the system behaviour. We use the PRISM probabilistic model checker to answer two important questions: 1) What is the minimum required incubation time to store a signal? And 2) How can we maximise the yield of the system? The results suggest that the incubation time can be reduced from 30 minutes to 5-15 minutes depending on the stack operation stage. In addition, the optimised model shows a 40% increase in the target stack yield. project “Synthetic Portabolomics: Leading the way at the crossroads of the Digital and the Bio Economies” (EP/N031962/1). Krasnogor was supported by the Royal Academy of Engineering under the Chairs in Emerging Technologies scheme.
{"title":"Modelling and Optimisation of a DNA Stack Nano-Device Using Probabilistic Model Checking","authors":"Bowen Li, N. Mackenzie, Ben Shirt-Ediss, N. Krasnogor, P. Zuliani","doi":"10.4230/LIPIcs.DNA.28.5","DOIUrl":"https://doi.org/10.4230/LIPIcs.DNA.28.5","url":null,"abstract":"A DNA stack nano-device is a bio-computing system that can read and write molecular signals based on DNA-DNA hybridisation and strand displacement. In vitro implementation of the DNA stack faces a number of challenges affecting the performance of the system. In this work, we apply probabilistic model checking to analyse and optimise the DNA stack system. We develop a model framework based on continuous-time Markov chains to quantitatively describe the system behaviour. We use the PRISM probabilistic model checker to answer two important questions: 1) What is the minimum required incubation time to store a signal? And 2) How can we maximise the yield of the system? The results suggest that the incubation time can be reduced from 30 minutes to 5-15 minutes depending on the stack operation stage. In addition, the optimised model shows a 40% increase in the target stack yield. project “Synthetic Portabolomics: Leading the way at the crossroads of the Digital and the Bio Economies” (EP/N031962/1). Krasnogor was supported by the Royal Academy of Engineering under the Chairs in Emerging Technologies scheme.","PeriodicalId":18854,"journal":{"name":"Mobile DNA","volume":"9 1","pages":"5:1-5:22"},"PeriodicalIF":4.9,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87676767","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
DNA Strand Displacement (DSD) systems model basic reaction rules, such as toehold-mediated strand displacement and 4-way branch migration, that modify complexes of bound DNA strands. DSD systems have been widely used to design and reason about the correctness of molecular programs, including implementations of logic circuits, neural networks, and Chemical Reaction Networks. Such implementations employ a valuable toolkit of mechanisms – sequences of basic reaction rules – that achieve catalysis, reduce errors (e.g., due to leak), or simulate simple computational units such as logic gates, both in solution and on surfaces. Expanding the DSD toolkit of DSD mechanisms can lead to new and better ways of programming with DNA. Here we introduce a new mechanism, which we call controlled reconfiguration . We describe one example where two single-stranded DSD complexes interact, changing the bonds in both complexes in a way that would not be possible for each independently on its own via the basic reaction rules allowed by the model. We use coupled reconfiguration to refer to instances of controlled reconfiguration in which two reactants change each other in this way. We note that our DSD model disallows pseudoknots and that properties of our coupled reconfiguration construction rely on this restriction of the model. A key feature of our coupled reconfiguration example, which distinguishes it from mechanisms (such as 3-way strand displacement or 4-way branch migration) that are typically used to implement molecular programs, is that the reactants are single-stranded. Leveraging this feature, we show how to use coupled reconfiguration to implement Chemical Reaction Networks (CRNs), with a DSD system that has both single-stranded signals (which represent the species of the CRN) and single-stranded fuels (which drive the CRN reactions). Our implementation also has other desirable properties; for example it is capable of implementing reversible CRNs and uses just two distinct toeholds. We discuss drawbacks of our implementation, particularly the reliance on pseudoknot-freeness for correctness, and suggest directions for future research that can provide further insight on the capabilities and limitations of controlled reconfiguration. computing (DSD) systems. a particularly well-studied abstract model of well-mixed chemical systems, in which many interesting programs can be and have been written [2, 3, 28, 36, 41]. Moreover, arbitrary CRNs can be transformed into DSD systems that implement the original CRN [7, 10, 30, 37, 39].
{"title":"A Coupled Reconfiguration Mechanism for Single-Stranded DNA Strand Displacement Systems","authors":"H. Johnson, A. Condon","doi":"10.4230/LIPIcs.DNA.28.3","DOIUrl":"https://doi.org/10.4230/LIPIcs.DNA.28.3","url":null,"abstract":"DNA Strand Displacement (DSD) systems model basic reaction rules, such as toehold-mediated strand displacement and 4-way branch migration, that modify complexes of bound DNA strands. DSD systems have been widely used to design and reason about the correctness of molecular programs, including implementations of logic circuits, neural networks, and Chemical Reaction Networks. Such implementations employ a valuable toolkit of mechanisms – sequences of basic reaction rules – that achieve catalysis, reduce errors (e.g., due to leak), or simulate simple computational units such as logic gates, both in solution and on surfaces. Expanding the DSD toolkit of DSD mechanisms can lead to new and better ways of programming with DNA. Here we introduce a new mechanism, which we call controlled reconfiguration . We describe one example where two single-stranded DSD complexes interact, changing the bonds in both complexes in a way that would not be possible for each independently on its own via the basic reaction rules allowed by the model. We use coupled reconfiguration to refer to instances of controlled reconfiguration in which two reactants change each other in this way. We note that our DSD model disallows pseudoknots and that properties of our coupled reconfiguration construction rely on this restriction of the model. A key feature of our coupled reconfiguration example, which distinguishes it from mechanisms (such as 3-way strand displacement or 4-way branch migration) that are typically used to implement molecular programs, is that the reactants are single-stranded. Leveraging this feature, we show how to use coupled reconfiguration to implement Chemical Reaction Networks (CRNs), with a DSD system that has both single-stranded signals (which represent the species of the CRN) and single-stranded fuels (which drive the CRN reactions). Our implementation also has other desirable properties; for example it is capable of implementing reversible CRNs and uses just two distinct toeholds. We discuss drawbacks of our implementation, particularly the reliance on pseudoknot-freeness for correctness, and suggest directions for future research that can provide further insight on the capabilities and limitations of controlled reconfiguration. computing (DSD) systems. a particularly well-studied abstract model of well-mixed chemical systems, in which many interesting programs can be and have been written [2, 3, 28, 36, 41]. Moreover, arbitrary CRNs can be transformed into DSD systems that implement the original CRN [7, 10, 30, 37, 39].","PeriodicalId":18854,"journal":{"name":"Mobile DNA","volume":"26 1","pages":"3:1-3:19"},"PeriodicalIF":4.9,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87141530","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A barrier to wider adoption of molecular computation is the difficulty of implementing arbitrary chemical reaction networks (CRNs) that are robust and replicate the kinetics of designed behavior. DNA Strand Displacement (DSD) cascades have been a favored technology for this purpose due to their potential to emulate arbitrary CRNs and known principles to tune their reaction rates. Progress on leakless cascades has demonstrated that DSDs can be arbitrarily robust to spurious “leak” reactions when incorporating systematic domain level redundancy. These improvements in robustness result in slower kinetics of designed reactions. Existing work has demonstrated the kinetic and thermodynamic effects of sequence mismatch introduction and elimination during displacement. We present a systematic, sequence modification strategy for optimizing the kinetics of leakless cascades without practical cost to their robustness. An in-depth case study explores the effects of this optimization when applied to a typical leakless translator cascade. Thermodynamic analysis of energy barriers and kinetic experimental data support that DSD cascades can be fast and robust.
{"title":"Fast and Robust Strand Displacement Cascades via Systematic Design Strategies","authors":"T. Kennedy, Cadence Pearce, Chris Thachuk","doi":"10.4230/LIPIcs.DNA.28.1","DOIUrl":"https://doi.org/10.4230/LIPIcs.DNA.28.1","url":null,"abstract":"A barrier to wider adoption of molecular computation is the difficulty of implementing arbitrary chemical reaction networks (CRNs) that are robust and replicate the kinetics of designed behavior. DNA Strand Displacement (DSD) cascades have been a favored technology for this purpose due to their potential to emulate arbitrary CRNs and known principles to tune their reaction rates. Progress on leakless cascades has demonstrated that DSDs can be arbitrarily robust to spurious “leak” reactions when incorporating systematic domain level redundancy. These improvements in robustness result in slower kinetics of designed reactions. Existing work has demonstrated the kinetic and thermodynamic effects of sequence mismatch introduction and elimination during displacement. We present a systematic, sequence modification strategy for optimizing the kinetics of leakless cascades without practical cost to their robustness. An in-depth case study explores the effects of this optimization when applied to a typical leakless translator cascade. Thermodynamic analysis of energy barriers and kinetic experimental data support that DSD cascades can be fast and robust.","PeriodicalId":18854,"journal":{"name":"Mobile DNA","volume":"s3-43 1","pages":"1:1-1:17"},"PeriodicalIF":4.9,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90833952","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-09-28DOI: 10.1101/2021.09.28.462135
Tobias Baril, Alex Hayward
Lepidoptera (butterflies and moths) are an important model system in ecology and evolution. A high-quality chromosomal genome assembly is available for the monarch butterfly (Danaus plexippus), but it lacks an in-depth transposable element (TE) annotation, presenting an opportunity to explore monarch TE dynamics and the impact of TEs on shaping the monarch genome. We find 6.21% of the monarch genome is comprised of TEs, a reduction of 6.85% compared to the original TE annotation performed on the draft genome assembly. Monarch TE content is low compared to two closely related species with available genomes, Danaus chrysippus (33.97% TE) and Danaus melanippus (11.87% TE). The biggest TE contributions to genome size in the monarch are LINEs and Penelope-like elements, and three newly identified families, r2-hero_dPle (LINE), penelope-1_dPle (Penelope-like), and hase2-1_dPle (SINE), collectively contribute 34.92% of total TE content. We find evidence of recent TE activity, with two novel Tc1 families rapidly expanding over recent timescales (tc1-1_dPle, tc1-2_dPle). LINE fragments show signatures of genomic deletions indicating a high rate of TE turnover. We investigate associations between TEs and wing colouration and immune genes and identify a three-fold increase in TE content around immune genes compared to other host genes. We provide a detailed TE annotation and analysis for the monarch genome, revealing a considerably smaller TE contribution to genome content compared to two closely related Danaus species with available genome assemblies. We identify highly successful novel DNA TE families rapidly expanding over recent timescales, and ongoing signatures of both TE expansion and removal highlight the dynamic nature of repeat content in the monarch genome. Our findings also suggest that insect immune genes are promising candidates for future interrogation of TE-mediated host adaptation.
{"title":"Migrators within migrators: exploring transposable element dynamics in the monarch butterfly, Danaus plexippus","authors":"Tobias Baril, Alex Hayward","doi":"10.1101/2021.09.28.462135","DOIUrl":"https://doi.org/10.1101/2021.09.28.462135","url":null,"abstract":"Lepidoptera (butterflies and moths) are an important model system in ecology and evolution. A high-quality chromosomal genome assembly is available for the monarch butterfly (Danaus plexippus), but it lacks an in-depth transposable element (TE) annotation, presenting an opportunity to explore monarch TE dynamics and the impact of TEs on shaping the monarch genome. We find 6.21% of the monarch genome is comprised of TEs, a reduction of 6.85% compared to the original TE annotation performed on the draft genome assembly. Monarch TE content is low compared to two closely related species with available genomes, Danaus chrysippus (33.97% TE) and Danaus melanippus (11.87% TE). The biggest TE contributions to genome size in the monarch are LINEs and Penelope-like elements, and three newly identified families, r2-hero_dPle (LINE), penelope-1_dPle (Penelope-like), and hase2-1_dPle (SINE), collectively contribute 34.92% of total TE content. We find evidence of recent TE activity, with two novel Tc1 families rapidly expanding over recent timescales (tc1-1_dPle, tc1-2_dPle). LINE fragments show signatures of genomic deletions indicating a high rate of TE turnover. We investigate associations between TEs and wing colouration and immune genes and identify a three-fold increase in TE content around immune genes compared to other host genes. We provide a detailed TE annotation and analysis for the monarch genome, revealing a considerably smaller TE contribution to genome content compared to two closely related Danaus species with available genome assemblies. We identify highly successful novel DNA TE families rapidly expanding over recent timescales, and ongoing signatures of both TE expansion and removal highlight the dynamic nature of repeat content in the monarch genome. Our findings also suggest that insect immune genes are promising candidates for future interrogation of TE-mediated host adaptation.","PeriodicalId":18854,"journal":{"name":"Mobile DNA","volume":"13 1","pages":""},"PeriodicalIF":4.9,"publicationDate":"2021-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"62334954","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-08-23DOI: 10.1186/s13100-021-00249-9
Erica M Briggs, Paolo Mita, Xiaoji Sun, Susan Ha, Nikita Vasilyev, Zev R Leopold, Evgeny Nudler, Jef D Boeke, Susan K Logan
Background: The autonomous retroelement Long Interspersed Element-1 (LINE-1) mobilizes though a copy and paste mechanism using an RNA intermediate (retrotransposition). Throughout human evolution, around 500,000 LINE-1 sequences have accumulated in the genome. Most of these sequences belong to ancestral LINE-1 subfamilies, including L1PA2-L1PA7, and can no longer mobilize. Only a small fraction of LINE-1 sequences, approximately 80 to 100 copies belonging to the L1Hs subfamily, are complete and still capable of retrotransposition. While silenced in most cells, many questions remain regarding LINE-1 dysregulation in cancer cells.
Results: Here, we optimized CRISPR Cas9 gRNAs to specifically target the regulatory sequence of the L1Hs 5'UTR promoter. We identified three gRNAs that were more specific to L1Hs, with limited binding to older LINE-1 sequences (L1PA2-L1PA7). We also adapted the C-BERST method (dCas9-APEX2 Biotinylation at genomic Elements by Restricted Spatial Tagging) to identify LINE-1 transcriptional regulators in cancer cells. Our LINE-1 C-BERST screen revealed both known and novel LINE-1 transcriptional regulators, including CTCF, YY1 and DUSP1.
Conclusion: Our optimization and evaluation of gRNA specificity and application of the C-BERST method creates a tool for studying the regulatory mechanisms of LINE-1 in cancer. Further, we identified the dual specificity protein phosphatase, DUSP1, as a novel regulator of LINE-1 transcription.
{"title":"Unbiased proteomic mapping of the LINE-1 promoter using CRISPR Cas9.","authors":"Erica M Briggs, Paolo Mita, Xiaoji Sun, Susan Ha, Nikita Vasilyev, Zev R Leopold, Evgeny Nudler, Jef D Boeke, Susan K Logan","doi":"10.1186/s13100-021-00249-9","DOIUrl":"10.1186/s13100-021-00249-9","url":null,"abstract":"<p><strong>Background: </strong>The autonomous retroelement Long Interspersed Element-1 (LINE-1) mobilizes though a copy and paste mechanism using an RNA intermediate (retrotransposition). Throughout human evolution, around 500,000 LINE-1 sequences have accumulated in the genome. Most of these sequences belong to ancestral LINE-1 subfamilies, including L1PA2-L1PA7, and can no longer mobilize. Only a small fraction of LINE-1 sequences, approximately 80 to 100 copies belonging to the L1Hs subfamily, are complete and still capable of retrotransposition. While silenced in most cells, many questions remain regarding LINE-1 dysregulation in cancer cells.</p><p><strong>Results: </strong>Here, we optimized CRISPR Cas9 gRNAs to specifically target the regulatory sequence of the L1Hs 5'UTR promoter. We identified three gRNAs that were more specific to L1Hs, with limited binding to older LINE-1 sequences (L1PA2-L1PA7). We also adapted the C-BERST method (dCas9-APEX2 Biotinylation at genomic Elements by Restricted Spatial Tagging) to identify LINE-1 transcriptional regulators in cancer cells. Our LINE-1 C-BERST screen revealed both known and novel LINE-1 transcriptional regulators, including CTCF, YY1 and DUSP1.</p><p><strong>Conclusion: </strong>Our optimization and evaluation of gRNA specificity and application of the C-BERST method creates a tool for studying the regulatory mechanisms of LINE-1 in cancer. Further, we identified the dual specificity protein phosphatase, DUSP1, as a novel regulator of LINE-1 transcription.</p>","PeriodicalId":18854,"journal":{"name":"Mobile DNA","volume":"12 1","pages":"21"},"PeriodicalIF":4.7,"publicationDate":"2021-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8381588/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9700931","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}