1
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Petroll R, West JA, Ogden M, McGinley O, Craig RJ, Coelho SM, Borg M. The expanded Bostrychia moritziana genome unveils evolution in the most diverse and complex order of red algae. Curr Biol 2025:S0960-9822(25)00508-1. [PMID: 40345196 DOI: 10.1016/j.cub.2025.04.044] [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: 02/24/2025] [Revised: 04/13/2025] [Accepted: 04/17/2025] [Indexed: 05/11/2025]
Abstract
Red algae are an ancient eukaryotic lineage that were among the first to evolve multicellularity. Although they share a common origin with modern-day plants and display complex multicellular development, comprehensive genome data from the most highly evolved red algal groups remain scarce. Here, we present a chromosome-level genome assembly of Bostrychia moritziana, a complex red seaweed in the Rhodomelaceae family of the Ceramiales-the largest and most diverse order of red algae. Contrary to the view that red algal genomes are typically small, we report significant genome size expansion in Bostrychia and other Ceramiales, which represents one of at least three independent expansion events in red algal evolution. Our analyses suggest that these expansions do not involve polyploidy or ancient whole-genome duplications, but in Bostrychia rather stem from the proliferation of a single lineage of giant Plavaka DNA transposons. Consistent with its enlarged genome, Bostrychia has an increased gene content shaped by de novo gene emergence and amplified gene families in common with other Ceramiales, providing insight into the genetic adaptations underpinning this successful and species-rich order. Finally, our sex-specific assemblies resolve the UV sex chromosomes in Bostrychia, which feature expanded gene-rich sex-linked regions. Notably, each sex chromosome harbors a three amino acid loop extension homeodomain (TALE-HD) transcription factor orthologous to ancient regulators of haploid-diploid transitions in other multicellular lineages. Together, our findings offer a unique perspective of the genomic adaptations driving red algal diversity and demonstrate how this red seaweed lineage can provide insight into the evolutionary origins and universal principles underpinning complex multicellularity.
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Affiliation(s)
- Romy Petroll
- Department of Algal Development and Evolution, Max Planck Institute for Biology, Tübingen 72076, Germany
| | - John A West
- School of BioSciences, University of Melbourne, Parkville, VIC 3010, Australia
| | - Michael Ogden
- Copenhagen Plant Science Center, Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg C 1871, Denmark
| | - Owen McGinley
- School of BioSciences, University of Melbourne, Parkville, VIC 3010, Australia
| | - Rory J Craig
- Department of Algal Development and Evolution, Max Planck Institute for Biology, Tübingen 72076, Germany
| | - Susana M Coelho
- Department of Algal Development and Evolution, Max Planck Institute for Biology, Tübingen 72076, Germany
| | - Michael Borg
- Department of Algal Development and Evolution, Max Planck Institute for Biology, Tübingen 72076, Germany.
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2
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Mangoni D, Mazzetti A, Ansaloni F, Simi A, Tartaglia GG, Pandolfini L, Gustincich S, Sanges R. From the genome's perspective: Bearing somatic retrotransposition to leverage the regulatory potential of L1 RNAs. Bioessays 2025; 47:e2400125. [PMID: 39520370 PMCID: PMC11755705 DOI: 10.1002/bies.202400125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2024] [Revised: 10/16/2024] [Accepted: 10/23/2024] [Indexed: 11/16/2024]
Abstract
Transposable elements (TEs) are mobile genomic elements constituting a big fraction of eukaryotic genomes. They ignite an evolutionary arms race with host genomes, which in turn evolve strategies to restrict their activity. Despite being tightly repressed, TEs display precisely regulated expression patterns during specific stages of mammalian development, suggesting potential benefits for the host. Among TEs, the long interspersed nuclear element (LINE-1 or L1) has been found to be active in neurons. This activity prompted extensive research into its possible role in cognition. So far, no specific cause-effect relationship between L1 retrotransposition and brain functions has been conclusively identified. Nevertheless, accumulating evidence suggests that interactions between L1 RNAs and RNA/DNA binding proteins encode specific messages that cells utilize to activate or repress entire transcriptional programs. We summarize recent findings highlighting the activity of L1 RNAs at the non-coding level during early embryonic and brain development. We propose a hypothesis suggesting a mutualistic relationship between L1 mRNAs and the host cell. In this scenario, cells tolerate a certain rate of retrotransposition to leverage the regulatory effects of L1s as non-coding RNAs on potentiating their mitotic potential. In turn, L1s benefit from the cell's proliferative state to increase their chance to mobilize.
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Affiliation(s)
- Damiano Mangoni
- Center for Human Technologies, Non‐Coding RNAs and RNA‐Based TherapeuticsIstituto Italiano di Tecnologia (IIT)GenovaItaly
| | - Aurora Mazzetti
- Area of NeuroscienceInternational School for Advanced Studies (SISSA)TriesteItaly
| | - Federico Ansaloni
- Center for Human Technologies, Non‐Coding RNAs and RNA‐Based TherapeuticsIstituto Italiano di Tecnologia (IIT)GenovaItaly
| | - Alessandro Simi
- Center for Human Technologies, Non‐Coding RNAs and RNA‐Based TherapeuticsIstituto Italiano di Tecnologia (IIT)GenovaItaly
| | - Gian Gaetano Tartaglia
- Center for Human Technologies, RNA Systems BiologyIstituto Italiano di Tecnologia (IIT)GenovaItaly
| | - Luca Pandolfini
- Center for Human Technologies, Non‐Coding RNAs and RNA‐Based TherapeuticsIstituto Italiano di Tecnologia (IIT)GenovaItaly
| | - Stefano Gustincich
- Center for Human Technologies, Non‐Coding RNAs and RNA‐Based TherapeuticsIstituto Italiano di Tecnologia (IIT)GenovaItaly
| | - Remo Sanges
- Center for Human Technologies, Non‐Coding RNAs and RNA‐Based TherapeuticsIstituto Italiano di Tecnologia (IIT)GenovaItaly
- Area of NeuroscienceInternational School for Advanced Studies (SISSA)TriesteItaly
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3
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Gualandi N, Minisini M, Bertozzo A, Brancolini C. Dissecting transposable elements and endogenous retroviruses upregulation by HDAC inhibitors in leiomyosarcoma cells: Implications for the interferon response. Genomics 2024; 116:110909. [PMID: 39103003 DOI: 10.1016/j.ygeno.2024.110909] [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: 04/04/2024] [Revised: 07/22/2024] [Accepted: 07/31/2024] [Indexed: 08/07/2024]
Abstract
Transposable elements (TEs) are of interest as immunomodulators for cancer therapies. TEs can fold into dsRNAs that trigger the interferon response. Here, we investigated the effect of different HDAC inhibitors (HDACIs) on the expression of TEs in leiomyosarcoma cells. Our data show that endogenous retroviruses (ERVs), especially ERV1 elements, are upregulated after treatment with HDAC1/2/3-specific inhibitors. Surprisingly, the interferon response was not activated. We observed an increase in A-to-I editing of upregulated ERV1. This could have an impact on the stability of dsRNAs and the activation of the interferon response. We also found that H3K27ac levels are increased in the LTR12 subfamilies, which could be regulatory elements controlling the expression of proapoptotic genes such as TNFRSF10B. In summary, we provide a detailed characterization of TEs modulation in response to HDACIs and suggest the use of HDACIs in combination with ADAR inhibitors to induce cell death and support immunotherapy in cancer.
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Affiliation(s)
- Nicolò Gualandi
- Department of Medicine, Università degli Studi di Udine, P.le Kolbe 4, 33100 Udine, Italy
| | - Martina Minisini
- Department of Medicine, Università degli Studi di Udine, P.le Kolbe 4, 33100 Udine, Italy
| | - Alessio Bertozzo
- Department of Medicine, Università degli Studi di Udine, P.le Kolbe 4, 33100 Udine, Italy
| | - Claudio Brancolini
- Department of Medicine, Università degli Studi di Udine, P.le Kolbe 4, 33100 Udine, Italy.
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4
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Di Giorgio E, Ranzino L, Tolotto V, Dalla E, Burelli M, Gualandi N, Brancolini C. Transcription of endogenous retroviruses in senescent cells contributes to the accumulation of double-stranded RNAs that trigger an anti-viral response that reinforces senescence. Cell Death Dis 2024; 15:157. [PMID: 38383514 PMCID: PMC10882003 DOI: 10.1038/s41419-024-06548-2] [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: 06/08/2023] [Revised: 02/02/2024] [Accepted: 02/08/2024] [Indexed: 02/23/2024]
Abstract
An important epigenetic switch marks the onset and maintenance of senescence. This allows transcription of the genetic programs that arrest the cell cycle and alter the microenvironment. Transcription of endogenous retroviruses (ERVs) is also a consequence of this epigenetic switch. In this manuscript, we have identified a group of ERVs that are epigenetically silenced in proliferating cells but are upregulated during replicative senescence or during various forms of oncogene-induced senescence, by RAS and Akt, or after HDAC4 depletion. In a HDAC4 model of senescence, removal of the repressive histone mark H3K27me3 is the plausible mechanism that allows the transcription of intergenic ERVs during senescence. We have shown that ERVs contribute to the accumulation of dsRNAs in senescence, which can initiate the antiviral response via the IFIH1-MAVS signaling pathway and thus contribute to the maintenance of senescence. This pathway, and MAVS in particular, plays an active role in shaping the microenvironment and maintaining growth arrest, two essential features of the senescence program.
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Affiliation(s)
- Eros Di Giorgio
- Laboratory of Biochemistry, Department of Medicine, Università degli Studi di Udine, p.le Kolbe 4, 33100, Udine, Italy
| | - Liliana Ranzino
- Laboratory of Epigenomics, Department of Medicine, Università degli Studi di Udine, p.le Kolbe 4, 33100, Udine, Italy
| | - Vanessa Tolotto
- Laboratory of Epigenomics, Department of Medicine, Università degli Studi di Udine, p.le Kolbe 4, 33100, Udine, Italy
| | - Emiliano Dalla
- Laboratory of Epigenomics, Department of Medicine, Università degli Studi di Udine, p.le Kolbe 4, 33100, Udine, Italy
| | - Matteo Burelli
- Laboratory of Biochemistry, Department of Medicine, Università degli Studi di Udine, p.le Kolbe 4, 33100, Udine, Italy
| | - Nicolò Gualandi
- Laboratory of Epigenomics, Department of Medicine, Università degli Studi di Udine, p.le Kolbe 4, 33100, Udine, Italy
| | - Claudio Brancolini
- Laboratory of Epigenomics, Department of Medicine, Università degli Studi di Udine, p.le Kolbe 4, 33100, Udine, Italy.
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5
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Liang Y, Qu X, Shah NM, Wang T. Towards targeting transposable elements for cancer therapy. Nat Rev Cancer 2024; 24:123-140. [PMID: 38228901 DOI: 10.1038/s41568-023-00653-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 12/04/2023] [Indexed: 01/18/2024]
Abstract
Transposable elements (TEs) represent almost half of the human genome. Historically deemed 'junk DNA', recent technological advancements have stimulated a wave of research into the functional impact of TEs on gene-regulatory networks in evolution and development, as well as in diseases including cancer. The genetic and epigenetic evolution of cancer involves the exploitation of TEs, whereby TEs contribute directly to cancer-specific gene activities. This Review provides a perspective on the role of TEs in cancer as being a 'double-edged sword', both promoting cancer evolution and representing a vulnerability that could be exploited in cancer therapy. We discuss how TEs affect transcriptome regulation and other cellular processes in cancer. We highlight the potential of TEs as therapeutic targets for cancer. We also summarize technical hurdles in the characterization of TEs with genomic assays. Last, we outline open questions and exciting future research avenues.
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Affiliation(s)
- Yonghao Liang
- Department of Genetics, Washington University School of Medicine, Saint Louis, MO, USA
- Center for Genome Sciences and Systems Biology, Washington University School of Medicine, Saint Louis, MO, USA
| | - Xuan Qu
- Department of Genetics, Washington University School of Medicine, Saint Louis, MO, USA
- Center for Genome Sciences and Systems Biology, Washington University School of Medicine, Saint Louis, MO, USA
| | - Nakul M Shah
- Division of Cancer Medicine, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Ting Wang
- Department of Genetics, Washington University School of Medicine, Saint Louis, MO, USA.
- Center for Genome Sciences and Systems Biology, Washington University School of Medicine, Saint Louis, MO, USA.
- McDonnell Genome Institute, Washington University School of Medicine, Saint Louis, MO, USA.
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6
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Contreras-Garrido A, Galanti D, Movilli A, Becker C, Bossdorf O, Drost HG, Weigel D. Transposon dynamics in the emerging oilseed crop Thlaspi arvense. PLoS Genet 2024; 20:e1011141. [PMID: 38295109 PMCID: PMC10881000 DOI: 10.1371/journal.pgen.1011141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Revised: 02/21/2024] [Accepted: 01/17/2024] [Indexed: 02/02/2024] Open
Abstract
Genome evolution is partly driven by the mobility of transposable elements (TEs) which often leads to deleterious effects, but their activity can also facilitate genetic novelty and catalyze local adaptation. We explored how the intraspecific diversity of TE polymorphisms might contribute to the broad geographic success and adaptive capacity of the emerging oil crop Thlaspi arvense (field pennycress). We classified the TE inventory based on a high-quality genome assembly, estimated the age of retrotransposon TE families and comprehensively assessed their mobilization potential. A survey of 280 accessions from 12 regions across the Northern hemisphere allowed us to quantify over 90,000 TE insertion polymorphisms (TIPs). Their distribution mirrored the genetic differentiation as measured by single nucleotide polymorphisms (SNPs). The number and types of mobile TE families vary substantially across populations, but there are also shared patterns common to all accessions. Ty3/Athila elements are the main drivers of TE diversity in T. arvense populations, while a single Ty1/Alesia lineage might be particularly important for transcriptome divergence. The number of retrotransposon TIPs is associated with variation at genes related to epigenetic regulation, including an apparent knockout mutation in BROMODOMAIN AND ATPase DOMAIN-CONTAINING PROTEIN 1 (BRAT1), while DNA transposons are associated with variation at the HSP19 heat shock protein gene. We propose that the high rate of mobilization activity can be harnessed for targeted gene expression diversification, which may ultimately present a toolbox for the potential use of transposition in breeding and domestication of T. arvense.
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Affiliation(s)
| | - Dario Galanti
- Plant Evolutionary Ecology, University of Tübingen, Tübingen, Germany
| | - Andrea Movilli
- Department of Molecular Biology, Max Planck Institute for Biology Tübingen, Tübingen, Germany
| | - Claude Becker
- LMU Biocenter, Faculty of Biology, Ludwig Maximilians University Munich, Martinsried, Germany
| | - Oliver Bossdorf
- Plant Evolutionary Ecology, University of Tübingen, Tübingen, Germany
| | - Hajk-Georg Drost
- Computational Biology Group, Max Planck Institute for Biology Tübingen,Tübingen, Germany
| | - Detlef Weigel
- Department of Molecular Biology, Max Planck Institute for Biology Tübingen, Tübingen, Germany
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Mangoni D, Simi A, Lau P, Armaos A, Ansaloni F, Codino A, Damiani D, Floreani L, Di Carlo V, Vozzi D, Persichetti F, Santoro C, Pandolfini L, Tartaglia GG, Sanges R, Gustincich S. LINE-1 regulates cortical development by acting as long non-coding RNAs. Nat Commun 2023; 14:4974. [PMID: 37591988 PMCID: PMC10435495 DOI: 10.1038/s41467-023-40743-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Accepted: 08/07/2023] [Indexed: 08/19/2023] Open
Abstract
Long Interspersed Nuclear Elements-1s (L1s) are transposable elements that constitute most of the genome's transcriptional output yet have still largely unknown functions. Here we show that L1s are required for proper mouse brain corticogenesis operating as regulatory long non-coding RNAs. They contribute to the regulation of the balance between neuronal progenitors and differentiation, the migration of post-mitotic neurons and the proportions of different cell types. In cortical cultured neurons, L1 RNAs are mainly associated to chromatin and interact with the Polycomb Repressive Complex 2 (PRC2) protein subunits enhancer of Zeste homolog 2 (Ezh2) and suppressor of zeste 12 (Suz12). L1 RNA silencing influences PRC2's ability to bind a portion of its targets and the deposition of tri-methylated histone H3 (H3K27me3) marks. Our results position L1 RNAs as crucial signalling hubs for genome-wide chromatin remodelling, enabling the fine-tuning of gene expression during brain development and evolution.
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Affiliation(s)
- Damiano Mangoni
- Central RNA Laboratory, Istituto Italiano di Tecnologia (IIT), Genova, Italy
| | - Alessandro Simi
- Central RNA Laboratory, Istituto Italiano di Tecnologia (IIT), Genova, Italy
| | - Pierre Lau
- Central RNA Laboratory, Istituto Italiano di Tecnologia (IIT), Genova, Italy
| | - Alexandros Armaos
- Central RNA Laboratory, Istituto Italiano di Tecnologia (IIT), Genova, Italy
| | - Federico Ansaloni
- Central RNA Laboratory, Istituto Italiano di Tecnologia (IIT), Genova, Italy
| | - Azzurra Codino
- Central RNA Laboratory, Istituto Italiano di Tecnologia (IIT), Genova, Italy
| | - Devid Damiani
- Central RNA Laboratory, Istituto Italiano di Tecnologia (IIT), Genova, Italy
| | - Lavinia Floreani
- Area of Neuroscience, International School for Advanced Studies (SISSA), Trieste, Italy
| | - Valerio Di Carlo
- Central RNA Laboratory, Istituto Italiano di Tecnologia (IIT), Genova, Italy
| | - Diego Vozzi
- Central RNA Laboratory, Istituto Italiano di Tecnologia (IIT), Genova, Italy
| | - Francesca Persichetti
- Department of Health Sciences and Research Center on Autoimmune and Allergic Diseases (CAAD), University of Piemonte Orientale (UPO), Novara, Italy
| | - Claudio Santoro
- Department of Health Sciences and Research Center on Autoimmune and Allergic Diseases (CAAD), University of Piemonte Orientale (UPO), Novara, Italy
| | - Luca Pandolfini
- Central RNA Laboratory, Istituto Italiano di Tecnologia (IIT), Genova, Italy
| | | | - Remo Sanges
- Central RNA Laboratory, Istituto Italiano di Tecnologia (IIT), Genova, Italy.
- Area of Neuroscience, International School for Advanced Studies (SISSA), Trieste, Italy.
| | - Stefano Gustincich
- Central RNA Laboratory, Istituto Italiano di Tecnologia (IIT), Genova, Italy.
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Spirito G, Filosi M, Domenici E, Mangoni D, Gustincich S, Sanges R. Exploratory analysis of L1 retrotransposons expression in autism. Mol Autism 2023; 14:22. [PMID: 37381037 DOI: 10.1186/s13229-023-00554-5] [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: 11/03/2022] [Accepted: 06/15/2023] [Indexed: 06/30/2023] Open
Abstract
BACKGROUND Autism spectrum disorder (ASD) is a set of highly heterogeneous neurodevelopmental diseases whose genetic etiology is not completely understood. Several investigations have relied on transcriptome analysis from peripheral tissues to dissect ASD into homogenous molecular phenotypes. Recently, analysis of changes in gene expression from postmortem brain tissues has identified sets of genes that are involved in pathways previously associated with ASD etiology. In addition to protein-coding transcripts, the human transcriptome is composed by a large set of non-coding RNAs and transposable elements (TEs). Advancements in sequencing technologies have proven that TEs can be transcribed in a regulated fashion, and their dysregulation might have a role in brain diseases. METHODS We exploited published datasets comprising RNA-seq data from (1) postmortem brain of ASD subjects, (2) in vitro cell cultures where ten different ASD-relevant genes were knocked out and (3) blood of discordant siblings. We measured the expression levels of evolutionarily young full-length transposable L1 elements and characterized the genomic location of deregulated L1s assessing their potential impact on the transcription of ASD-relevant genes. We analyzed every sample independently, avoiding to pool together the disease subjects to unmask the heterogeneity of the molecular phenotypes. RESULTS We detected a strong upregulation of intronic full-length L1s in a subset of postmortem brain samples and in in vitro differentiated neurons from iPSC knocked out for ATRX. L1 upregulation correlated with an high number of deregulated genes and retained introns. In the anterior cingulate cortex of one subject, a small number of significantly upregulated L1s overlapped with ASD-relevant genes that were significantly downregulated, suggesting the possible existence of a negative effect of L1 transcription on host transcripts. LIMITATIONS Our analyses must be considered exploratory and will need to be validated in bigger cohorts. The main limitation is given by the small sample size and by the lack of replicates for postmortem brain samples. Measuring the transcription of locus-specific TEs is complicated by the repetitive nature of their sequence, which reduces the accuracy in mapping sequencing reads to the correct genomic locus. CONCLUSIONS L1 upregulation in ASD appears to be limited to a subset of subjects that are also characterized by a general deregulation of the expression of canonical genes and an increase in intron retention. In some samples from the anterior cingulate cortex, L1s upregulation seems to directly impair the expression of some ASD-relevant genes by a still unknown mechanism. L1s upregulation may therefore identify a group of ASD subjects with common molecular features and helps stratifying individuals for novel strategies of therapeutic intervention.
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Affiliation(s)
- Giovanni Spirito
- Scuola Internazionale Superiore di Studi Avanzati (SISSA), Area of Neuroscience, Via Bonomea 265, 34136, Trieste, Italy
- Central RNA Laboratory, Istituto Italiano di Tecnologia - IIT, Via Enrico Melen 83, Building B, 16152, Genoa, Italy
- CMP3vda, Via Lavoratori Vittime del Col Du Mont 28, Aosta, Italy
| | - Michele Filosi
- Department of Cellular, Computational and Integrative Biology (CIBIO), University of Trento, Trento, TN, Italy
- Eurac Research, Institute for Biomedicine, Bolzano, BZ, Italy
| | - Enrico Domenici
- Department of Cellular, Computational and Integrative Biology (CIBIO), University of Trento, Trento, TN, Italy
- Fondazione The Microsoft Research - University of Trento Centre for Computational and Systems Biology (COSBI), Rovereto, TN, Italy
| | - Damiano Mangoni
- Central RNA Laboratory, Istituto Italiano di Tecnologia - IIT, Via Enrico Melen 83, Building B, 16152, Genoa, Italy
| | - Stefano Gustincich
- Central RNA Laboratory, Istituto Italiano di Tecnologia - IIT, Via Enrico Melen 83, Building B, 16152, Genoa, Italy.
- CMP3vda, Via Lavoratori Vittime del Col Du Mont 28, Aosta, Italy.
| | - Remo Sanges
- Scuola Internazionale Superiore di Studi Avanzati (SISSA), Area of Neuroscience, Via Bonomea 265, 34136, Trieste, Italy.
- Central RNA Laboratory, Istituto Italiano di Tecnologia - IIT, Via Enrico Melen 83, Building B, 16152, Genoa, Italy.
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9
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Ansaloni F, Gustincich S, Sanges R. In silico characterisation of minor wave genes and LINE-1s transcriptional dynamics at murine zygotic genome activation. Front Cell Dev Biol 2023; 11:1124266. [PMID: 37389353 PMCID: PMC10300423 DOI: 10.3389/fcell.2023.1124266] [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: 12/14/2022] [Accepted: 06/05/2023] [Indexed: 07/01/2023] Open
Abstract
Introduction: In mouse, the zygotic genome activation (ZGA) is coordinated by MERVL elements, a class of LTR retrotransposons. In addition to MERVL, another class of retrotransposons, LINE-1 elements, recently came under the spotlight as key regulators of murine ZGA. In particular, LINE-1 transcripts seem to be required to switch-off the transcriptional program started by MERVL sequences, suggesting an antagonistic interplay between LINE-1 and MERVL pathways. Methods: To better investigate the activities of LINE-1 and MERVL elements at ZGA, we integrated publicly available transcriptomics (RNA-seq), chromatin accessibility (ATAC-seq) and Pol-II binding (Stacc-seq) datasets and characterised the transcriptional and epigenetic dynamics of such elements during murine ZGA. Results: We identified two likely distinct transcriptional activities characterising the murine zygotic genome at ZGA onset. On the one hand, our results confirmed that ZGA minor wave genes are preferentially transcribed from MERVL-rich and gene-dense genomic compartments, such as gene clusters. On the other hand, we identified a set of evolutionary young and likely transcriptionally autonomous LINE-1s located in intergenic and gene-poor regions showing, at the same stage, features such as open chromatin and RNA Pol II binding suggesting them to be, at least, poised for transcription. Discussion: These results suggest that, across evolution, transcription of two different classes of transposable elements, MERVLs and LINE-1s, have likely been confined in genic and intergenic regions respectively in order to maintain and regulate two successive transcriptional programs at ZGA.
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Affiliation(s)
- Federico Ansaloni
- Area of Neuroscience, Scuola Internazionale Superiore di Studi Avanzati (SISSA), Trieste, Italy
- Central RNA Laboratory, Istituto Italiano di Tecnologia—IIT, Genova, Italy
| | - Stefano Gustincich
- Central RNA Laboratory, Istituto Italiano di Tecnologia—IIT, Genova, Italy
| | - Remo Sanges
- Area of Neuroscience, Scuola Internazionale Superiore di Studi Avanzati (SISSA), Trieste, Italy
- Central RNA Laboratory, Istituto Italiano di Tecnologia—IIT, Genova, Italy
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10
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Esposito M, Gualandi N, Spirito G, Ansaloni F, Gustincich S, Sanges R. Transposons Acting as Competitive Endogenous RNAs: In-Silico Evidence from Datasets Characterised by L1 Overexpression. Biomedicines 2022; 10:biomedicines10123279. [PMID: 36552034 PMCID: PMC9776036 DOI: 10.3390/biomedicines10123279] [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: 10/30/2022] [Revised: 12/07/2022] [Accepted: 12/11/2022] [Indexed: 12/23/2022] Open
Abstract
LINE L1 are transposable elements that can replicate within the genome by passing through RNA intermediates. The vast majority of these element copies in the human genome are inactive and just between 100 and 150 copies are still able to mobilize. During evolution, they could have been positively selected for beneficial cellular functions. Nonetheless, L1 deregulation can be detrimental to the cell, causing diseases such as cancer. The activity of miRNAs represents a fundamental mechanism for controlling transcript levels in somatic cells. These are a class of small non-coding RNAs that cause degradation or translational inhibition of their target transcripts. Beyond this, competitive endogenous RNAs (ceRNAs), mostly made by circular and non-coding RNAs, have been seen to compete for the binding of the same set of miRNAs targeting protein coding genes. In this study, we have investigated whether autonomously transcribed L1s may act as ceRNAs by analyzing public dataset in-silico. We observed that genes sharing miRNA target sites with L1 have a tendency to be upregulated when L1 are overexpressed, suggesting the possibility that L1 might act as ceRNAs. This finding will help in the interpretation of transcriptomic responses in contexts characterized by the specific activation of transposons.
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Affiliation(s)
- Mauro Esposito
- Computational Genomics Laboratory, Area of Neuroscience, Scuola Internazionale Superiore di Studi Avanzati (SISSA), 34136 Trieste, Italy
| | - Nicolò Gualandi
- Computational Genomics Laboratory, Area of Neuroscience, Scuola Internazionale Superiore di Studi Avanzati (SISSA), 34136 Trieste, Italy
| | - Giovanni Spirito
- Computational Genomics Laboratory, Area of Neuroscience, Scuola Internazionale Superiore di Studi Avanzati (SISSA), 34136 Trieste, Italy
- CMP3vda, via Lavoratori Vittime del Col Du Mont 28, 11100 Aosta, Italy
| | - Federico Ansaloni
- Computational Genomics Laboratory, Area of Neuroscience, Scuola Internazionale Superiore di Studi Avanzati (SISSA), 34136 Trieste, Italy
- Central RNA Laboratory, Istituto Italiano di Tecnologia, 16132 Genova, Italy
| | - Stefano Gustincich
- CMP3vda, via Lavoratori Vittime del Col Du Mont 28, 11100 Aosta, Italy
- Central RNA Laboratory, Istituto Italiano di Tecnologia, 16132 Genova, Italy
| | - Remo Sanges
- Computational Genomics Laboratory, Area of Neuroscience, Scuola Internazionale Superiore di Studi Avanzati (SISSA), 34136 Trieste, Italy
- Central RNA Laboratory, Istituto Italiano di Tecnologia, 16132 Genova, Italy
- Correspondence:
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