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opencc-by-4.0Dec 2020View details →

InpactorDB: A Plant classified lineage-level LTR retrotransposon reference library for free-alignment methods based on Machine Learning

LTR retrotransposons are mobile elements that make up the major part of most plant genomes. Their identification and annotation via bioinformatics approaches represent a major challenge in the era of massive plant genome sequencing. In addition to their involvement in the variation in genome size, these elements are also associated in the function and structure of different chromosomal regions and in the alteration of the function of coding regions, among others. Several plant retrotransposon sequence databases of LTR retrotransposons are available with public access such as PGSB, RepetDB or restricted access such as Repbase. Although they are useful for approaches to identify LTR-RTs in new genomes by similarity, the elements of these databases are not classified down to the lineage/family level. with great depth.  Here, we present InpactorDB a semi-curated dataset composed of 130,511 elements from 195 plant genomes (belonging to 108 plant species), classified down to the lineage level. This data set has been used to train two deep neural networks (one fully connected and one convolutional) for fast classification of elements. Used in lineage-level classification approaches, we obtain a score above 98% of F1-score, precision and recall.  In order to classify elements of the ‘LTR_STRUC’ and ‘EDTA’ datasets, we used the methodology proposed by Inpactor, which uses homology-based strategy with known coding domains belonging to LTR-RTs. We utilized the RexDB  domain library as reference. LTR-RTs were classified into superfamilies, Gypsy (RLG) or Copia (RLC) and sub-classified into lineages according to the similarities of five different amino acid reference domains (GAG, AP, RT, RNAseH, and INT domains). In addition, we applied filters to remove keep only intact elements: 1) to remove predicted elements with domains from two different superfamilies (i.e. Gypsy and Copia), 2) or elements with domains belonging to two or more different lineages, 3) to remove elements with lengths different than those reported by Gypsy Database (GyDB) with a tolerance of 20%, 4) to delete incomplete elements which has less than three identified domains, and 5) to remove elements with insertions of TE class II (reported in Repbase).  The final non-redundant version of InpactorDB consists of 67,305 LTR retrotransposons. Both redundant and non-redundant versions of InpactorDB are available in Fasta format in which sequences have identifiers with the following general Identification code: >Superfamily-Lineage-plant_family-specie-source-length-ID, Where Superfamily can is either RLC (for Copia) or RLG (for Gypsy), Lineage/family follows following the RexDB nomenclature, source (can be Repbase, RepetDB, PGSB, LTR_STRUC or EDTA datasets), length, and ID, is a unique number which identify each element inside the InpactorDB.

opencc-by-4.0Aug 2022View details →

High nucleotide similarity of three Copia lineage LTR retrotransposons among plant genomes

Transposable elements (TEs) are mobile genetic elements found in the majority of eukaryotic genomes. TEs deeply impact the structure and evolution of chromosomes and can induce mutations affecting coding genes. In plants, the major group of TEs is Long Terminal Repeats retrotransposons (LTR-RT). They are classified into superfamilies (Gypsy, Copia) and sub-classified into lineages. Horizontal transfer (HT), defined as the nonsexual transmission of genetic material between species, is a process allowing LTR-RTs to invade a new genome. Although this phenomenon was considered rare, recent studies demonstrate numerous transfers of LTR-RTs, suggesting that HT may be more frequent than initially estimated. This study aims to determine which LTR-RT lineages are shared with high similarity among 69 reference plant genomes. We identified and classified 88,450 LTR-RTs and determined 143 cases (involving 94 elements) of high similarities between pairs of genomes. Most of them involved three Copia lineages (Oryco/Ivana, Retrofit/Ale and Tork/Tar/Ikeros). A detailed analysis of three cases of high similarities involving Tork/Tar/Ikeros group shows a patchy distribution of the elements and phylogenetic incongruities, indicating they originated from potential HTs. Overall, our results suggest that Copia LTR-RTs share outstanding similarity between very distant species and may probably be more involved in HT mechanisms.

opencc-by-4.0May 2024View details →

Dataset for training SENMAP, a automatic tool to curate LTR-retrotransposons using convolutional neural networks

Transposable elements (TEs) are specific structures of the genome of species, which can move from one location to another. For that reason, they can cause mutations or changes that can be negative, such as the appearance of diseases, or beneficial, such as participating in fundamental roles in the evolution of genomes and genetic diversity. Long Terminal Repeat retrotransposons (LTR-RT) are the most abundant in plant species, hence the importance of studying these structures in particular. Over the time, these elements can suffer changes called nested insertions, which can inactivate or modify the functioning of the element, for that they are no longer consider as intact element and cannot be used for identification and classification studies. We create a dataset containing 56,442 LTR-RTs targed as "non-intact" elements and 49,215 considered as "intact".  We formated the sequences IDs in order to keep relevant information as the superfamily and the lineage, as well as the category (Negative for "non-intact" and Positive for "intact" elements).   This dataset (the npy files obtained from the fasta file) was used for training SENMAP, a convolutional neural network architecture to obtain intact LTR-RT sequences in plant genomes, which is composed by four convolutional layers, LeakyReLU as activation function and BinaryFocalLoss as loss function. Achieving an F1-score percentage of 91.37% with test data, identifying low quality sequences rapidly and efficiently, contributing to curate libraries of LTR retrotransposons of plants genomes published in large-scale sequencing projects due to the post-genomic era.

opencc-by-4.0Oct 2022View details →

How to start a LINE: 5' switching rejuvenates LINE retrotransposons in tobacco and related Nicotiana species

Here we provide supplementary data for our study of Retrotransosable Elements (RTE) in tobacco and other Nightshades.   In contrast to their conserved mammalian counterparts, plant long interspersed nuclear elements (LINEs) are highly variable, splitting into many low-copy families. Curiously, LINE families from the RTE clade retain a stronger sequence conservation and hence reach higher copy numbers. The cause of this RTE-typical property is not yet understood, but would help clarifying why some transposable elements are removed quickly whereas others persist in plant genomes. Here, we bring forward the first detailed study of RTE LINE structure, diversity and evolution in plants. For this, we argue that the Nightshade family is the ideal taxon to follow the evolutionary trajectories of RTE LINEs, given their high abundance, recent activity and partnership to non-autonomous elements. Using bioinformatic, cytogenetic and molecular approaches, we detect 4029 full-length RTE LINEs across the Solanaceae. We finely characterize and manually curate a core group of 458 full-length LINEs in allotetraploid tobacco, show amplification after polyploidization, and trace hybridization events by RTE LINE composition of parental genomes. Finally, we reveal the role of the untranslated regions (UTRs) as causes for the unique RTE LINE amplification and evolution pattern in plants: On one hand, we detect a highly conserved motif at the 3’ UTR, suggesting strong selective constraints acting on the RTE terminus. On the other hand, we observed successive rounds of 5’ UTR cycling, constantly rejuvenating the promoter sequences. This interplay between exchangeable promoters and conserved LINE bodies and 3’ UTR likely allows RTE LINEs to persist and thrive in plant genomes.   This dataset contains the nHMMs and their underlying alignments that were used for RTE detection (S1 - S4). In addition,  we provide the final multiple nucleotide alignment of 458 full length SolRTE LINEs (S5) and an alignment and an annotated list of 19 representative SolRTE LINEs of tobacco (S6 - S7). Sequence names include information on the analysed genome assembly of Nicotiana tabacum Cultivar ‘TN90’ (GCA_000715135.1; Sierro et al. 2014): scaffold position (scaffold identifier; start and stop position), and sequence orientation (forward = plus; reverse = minus). Sequences of the probes used for Fluorescent in situ hybridisation (FISH) were provided as S8.

opencc-by-4.0Oct 2023View details →

Plant Cassandra retrotransposons: LTR alignment data and Astereaceae full length annotation

Supplemental material to the article:  "Evolving together: Cassandra retrotransposons gradually mirror promoter mutations of the 5S rRNA genes"Abstract: The 5S rRNA genes are among the most conserved nucleotide sequences across all species. Similar to the 5S preservation we observe the occurrence of 5S-related non-autonomous retrotransposons, so-called Cassandra. Cassandras harbor highly conserved 5S rDNA-related sequences within their long terminal repeats (LTRs), advantageously providing them with the 5S internal promoter. However, the dynamics of Cassandra retrotransposon evolution in the context of 5S rRNA gene sequence information and structural arrangement are still unclear, especially: 1) do we observe repeated or gradual domestication of the highly conserved 5S promoter by Cassandras and 2) do changes in 5S organization such as in the linked 35S-5S rDNA arrangements impact Cassandra evolution? Here, we show evidence for gradual co-evolution of Cassandra sequences with their corresponding 5S rDNAs. To follow the impact of 5S rDNA variability on Cassandra TEs, we investigate the Asteraceae family where highly variable 5S rDNAs, including 5S promoter shifts and both linked and separated 35S-5S rDNA arrangements have been reported. Cassandras within the Asteraceae mirror 5S rDNA promoter mutations of their host genome, likely as an adaptation to the host's specific 5S transcription factors and hence compensating for evolutionary changes in the 5S rDNA sequence. Changes in the 5S rDNA sequence and in Cassandras seem uncorrelated with linked/separated rDNA arrangements. We place all these observations into the context of angiosperm 5S rDNA-Cassandra evolution, discuss Cassandra's origin hypotheses (single or multiple) and Cassandra's possible impact on rDNA and plant genome organization, giving new insights into the interplay of ribosomal genes and transposable elements.

opencc-zeroDec 2020View details →

Population analysis of retrotransposons in giraffe genomes supports RTE decline and widespread LINE1 activity in Giraffidae

The majority of structural variation in genomes is caused by insertions of transposable elements (TEs). In mammalian genomes, the main TE fraction is made up of autonomous and non-autonomous non-LTR retrotransposons commonly known as LINEs and SINEs (Long and Short Interspersed Nuclear Elements). Here we present one of the first population-level analysis of TE insertions in a non-model organism, the giraffe. Giraffes are ruminant artiodactyls, one of the few mammalian groups with genomes that are colonized by putatively active LINEs of two different clades of non-LTR retrotransposons, namely the LINE1 and RTE/BovB LINEs as well as their associated SINEs. We analyzed TE insertions of both types, and their associated SINEs in three giraffe genome assemblies, as well as across a population level sampling of 48 individuals covering all extant giraffe species. Results The comparative genome screen identified 139,525 recent LINE1 and RTE insertions in the sampled giraffe population. The analysis revealed a drastically reduced RTE activity in giraffes, whereas LINE1 is still actively propagating in the genomes of extant (sub)-species. In concert with the extremely low activity of the giraffe RTE, we also found that RTE-dependent SINEs, namely Bov-tA and Bov-A2, have been virtually immobile in the last 2 million years. Despite the high current activity of the giraffe LINE1, we did not find evidence for the presence of currently active LINE1-dependent SINEs. TE insertion heterozygosity rates differ among the different (sub)-species, likely due to divergent population histories. Conclusions The horizontally transferred RTE/BovB and its derived SINEs appear to be close to inactivation and subsequent extinction in the genomes of extant giraffe species. This is the first time that the decline of a TE family has been meticulously analyzed from a population genetics perspective. Our study shows how detailed information about past and present TE activity can be obtained by analyzing large-scale population-level genomic data sets.

opencc-by-4.0Jul 2024View details →

BousiosLab/Centrophilic retrotransposons in Arabidopsis

Files and scripts used in the paper that describes centrophilic retrotransposons in Arabidopsis

opencc-by-4.0May 2018View details →

Dataset from: Horizontal transfer of BovB and L1 retrotransposons in eukaryotes

Background: Transposable elements are mobile DNA sequences, colloquially known as jumping genes because of their ability to replicate to new genomic locations. TEs can jump  between organisms or species when given a vector of transfer, such as a tick or a virus, in a process known as horizontal transfer. Here, we propose that LINE-1(L1) and Bovine-B (BovB), the two most abundant transposable element families in mammals, were initially introduced as foreign DNA via ancient horizontal transfer events. Results: Using analyses of over 759 plant, fungal and animal genomes, we identify multiple possible L1 horizontal transfer events in eukaryotic species, primarily involving Tx-like L1s in marine eukaryotes. We also extend the BovB paradigm by increasing the number of estimated transfer events compared to previous studies, finding new parasite vectors of transfer such as bed bug, leech, and locust, and BovB occurrences in new lineages such as bat and frog. Given that these transposable elements have colonized more than half of the genome sequence in today's mammals, our results support a role for horizontal transfer in causing long-term genomic change in new host organisms. Conclusions: We describe extensive horizontal transfer of BovB retrotransposons and provide the first evidence that L1 elements can also undergo horizontal transfer. With the advancement of genome sequencing technologies and bioinformatics tools, we anticipate our study to be a valuable resource for inferring horizontal transfer from large-scale genomic data. Dataset: The deposited dataset contains the identified TE sequences (L1 and BovB) from all genomes and the putative horizontal transfer clusters described in the text. See Additional File 1 (Tables S1-6) and Additional File 2 (Figures S1-55) for detailed descriptions of the sequences and clusters.

opencc-by-4.0Jul 2019View details →

Retrotransposon insertions can initiate colorectal cancer and are associated with poor survival

This dataset is related to "Retrotransposon insertions can initiate colorectal cancer and are associated with poor survival" (Cajuso et al.). Abstract: Genomic instability pathways in colorectal cancer (CRC) have been extensively studied, but the role of retrotransposition in colorectal carcinogenesis remains poorly understood. Although retrotransposons are usually repressed, they become active in several human cancers, in particular those of the gastrointestinal tract. Here we characterize retrotransposon insertions in 202 colorectal tumor whole genomes and investigate their associations with molecular and clinical characteristics. We find highly variable retrotransposon activity among tumors and identify recurrent insertions in 15 known cancer genes. In approximately 1% of the cases we identify insertions in APC, likely to be tumor-initiating events. Insertions are positively associated with the CpG island methylator phenotype and the genomic fraction of allelic imbalance. Clinically, high number of insertions is independently associated with poor disease-specific survival. Sample description:  A signed informed consent was obtained for as many human participants as possible. In cases without a signed informed consent, an authorization from the National Supervisory Authority for Welfare and Health (Dnro 421/04/044/06, Dnro 8048/06.01.03.01/2014, Dnro 358/32/300/05, Dnro 1476/06.01.03.01/2012) was obtained as stated in Finnish law. The study has been reviewed by the Ethics Committee of the Hospital district of Helsinki and Uusima (Dnro 133/E8/03, 408/13/03/03/2009). Permission to use patient information was obtained from the National Institute for Health and Welfare (Dnro 53/07/2000, Dnro THL/1071/5.05.00/2011, Dnro THL/151/5.05.00/2017).   RNA sequencing: Total RNA from consecutive cryosections was extracted using RNeasy Mini Kit (Qiagen) from 34 tumors that displayed more than 50% of cancer cell percentage (HE staining of cryosections) and RNA integrity>6 (Agilent RNA 6000, Agilent 2100 Bioanalyzer). Paired-end RNA sequencing was performed on the Illumina Hiseq 2000. RNA-seq data was processed using Kallisto (version 0.43.0) software. Kallisto quantification was executed in paired-end mode and aligned against the Ensembl Human reference transcriptome (GRCh37_79). Quantification results from Kallisto were normalized and aggregated to gene-level utilizing sleuth (version 0.28.1) R package with default filtering settings.

opencc-by-4.0Jun 2024View details →

Additional files for Horvath et al., 2024. Detection and classification of long terminal repeat sequences in plant LTR-retrotransposons and their analysis using explainable machine learning.

Additional data for Horvath et al., 2024 (source code freeze, models, data, supplementary figures, tables and files(.

opencc-zeroOct 2019View details →

Data from: Diversity, dynamics and effects of long terminal repeat retrotransposons in the model grass Brachypodium distachyon

<ul> <li>Transposable elements (TEs) are the main reason for the high plasticity of plant genomes, where they occur as communities of diverse evolutionary lineages. Because research has typically focused on single abundant families or summarized TEs at a coarse taxonomic level, our knowledge about how these lineages differ in their effects on genome evolution is still rudimentary. </li> <li>Here we investigate the community composition and dynamics of 32 long terminal repeat retrotransposon (LTR-RT) families in the 272 Mb genome of the Mediterranean grass Brachypodium distachyon. </li> <li>We find that much of the recent transpositional activity in the B. distachyon genome is due to centromeric Gypsy families and Copia elements belonging to the Angela lineage. With a half-life as low as 66 ky, the latter are the most dynamic part of the genome and an important source of within-species polymorphisms. Second, GC-rich Gypsy elements of the Retand lineage are the most abundant TEs in the genome. Their presence explains more than 20 percent of the genome-wide variation in GC content and is associated with higher methylation levels. </li> <li>Our study shows how individual TE lineages change the genetic and epigenetic constitution of the host beyond simple changes in genome size. </li> </ul>

publicMay 2020View details →

Data from: Diversity, dynamics and effects of long terminal repeat retrotransposons in the model grass Brachypodium distachyon

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publicNov 2025View details →

Data from: A 4-lineage statistical suite to evaluate the support of large-scale retrotransposon insertion data to reconstruct evolutionary trees

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