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Cheah HL, Citartan M, Lee LP, Ahmed SA, Salleh MZ, Teh LK, Tang TH. Exploring the transcription start sites and other genomic features facilitates the accurate identification and annotation of small RNAs across multiple stress conditions in Mycobacterium tuberculosis. Funct Integr Genomics 2024; 24:160. [PMID: 39264475 DOI: 10.1007/s10142-024-01437-5] [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: 06/25/2024] [Revised: 08/22/2024] [Accepted: 08/23/2024] [Indexed: 09/13/2024]
Abstract
Mycobacterium tuberculosis (MTB) is a pathogen that is known for its ability to persist in harsh environments and cause chronic infections. Understanding the regulatory networks of MTB is crucial for developing effective treatments. Small regulatory RNAs (sRNAs) play important roles in gene expression regulation in all kingdoms of life, and their classification based solely on genomic location can be imprecise due to the computational-based prediction of protein-coding genes in bacteria, which often neglects segments of mRNA such as 5'UTRs, 3'UTRs, and intercistronic regions of operons. To address this issue, our study simultaneously discovered genomic features such as TSSs, UTRs, and operons together with sRNAs in the M. tuberculosis H37Rv strain (ATCC 27294) across multiple stress conditions. Our analysis identified 1,376 sRNA candidates and 8,173 TSSs in MTB, providing valuable insights into its complex regulatory landscape. TSS mapping enabled us to classify these sRNAs into more specific categories, including promoter-associated sRNAs, 5'UTR-derived sRNAs, 3'UTR-derived sRNAs, true intergenic sRNAs, and antisense sRNAs. Three of these sRNA candidates were experimentally validated using 3'-RACE-PCR: predictedRNA_0240, predictedRNA_0325, and predictedRNA_0578. Future characterization and validation are necessary to fully elucidate the functions and roles of these sRNAs in MTB. Our study is the first to simultaneously unravel TSSs and sRNAs in MTB and demonstrate that the identification of other genomic features, such as TSSs, UTRs, and operons, allows for more accurate and specific classification of sRNAs.
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Affiliation(s)
- Hong-Leong Cheah
- Advanced Medical and Dental Institute (AMDI), Universiti Sains Malaysia, Bertam, 13200, Kepala Batas, Penang, Malaysia
- Monash University Malaysia Genomics Platform, School of Science, Monash University Malaysia, Bandar Sunway, 47500, Subang Jaya, Selangor, Malaysia
| | - Marimuthu Citartan
- Advanced Medical and Dental Institute (AMDI), Universiti Sains Malaysia, Bertam, 13200, Kepala Batas, Penang, Malaysia.
| | - Li-Pin Lee
- Advanced Medical and Dental Institute (AMDI), Universiti Sains Malaysia, Bertam, 13200, Kepala Batas, Penang, Malaysia
| | - Siti Aminah Ahmed
- Advanced Medical and Dental Institute (AMDI), Universiti Sains Malaysia, Bertam, 13200, Kepala Batas, Penang, Malaysia
| | - Mohd Zaki Salleh
- Integrative Pharmacogenomics Institute (iPROMISE), Universiti Teknologi MARA (UiTM) Selangor, Bandar Puncak Alam, Selangor, Malaysia
- Faculty of Pharmacy, Universiti Teknologi MARA (UiTM) Selangor, Bandar Puncak Alam, Selangor, Malaysia
| | - Lay Kek Teh
- Integrative Pharmacogenomics Institute (iPROMISE), Universiti Teknologi MARA (UiTM) Selangor, Bandar Puncak Alam, Selangor, Malaysia
- Faculty of Pharmacy, Universiti Teknologi MARA (UiTM) Selangor, Bandar Puncak Alam, Selangor, Malaysia
| | - Thean-Hock Tang
- Advanced Medical and Dental Institute (AMDI), Universiti Sains Malaysia, Bertam, 13200, Kepala Batas, Penang, Malaysia.
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Ferrari R, Grandi N, Tramontano E, Dieci G. Retrotransposons as Drivers of Mammalian Brain Evolution. Life (Basel) 2021; 11:life11050376. [PMID: 33922141 PMCID: PMC8143547 DOI: 10.3390/life11050376] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 04/20/2021] [Accepted: 04/21/2021] [Indexed: 12/11/2022] Open
Abstract
Retrotransposons, a large and diverse class of transposable elements that are still active in humans, represent a remarkable force of genomic innovation underlying mammalian evolution. Among the features distinguishing mammals from all other vertebrates, the presence of a neocortex with a peculiar neuronal organization, composition and connectivity is perhaps the one that, by affecting the cognitive abilities of mammals, contributed mostly to their evolutionary success. Among mammals, hominids and especially humans display an extraordinarily expanded cortical volume, an enrichment of the repertoire of neural cell types and more elaborate patterns of neuronal connectivity. Retrotransposon-derived sequences have recently been implicated in multiple layers of gene regulation in the brain, from transcriptional and post-transcriptional control to both local and large-scale three-dimensional chromatin organization. Accordingly, an increasing variety of neurodevelopmental and neurodegenerative conditions are being recognized to be associated with retrotransposon dysregulation. We review here a large body of recent studies lending support to the idea that retrotransposon-dependent evolutionary novelties were crucial for the emergence of mammalian, primate and human peculiarities of brain morphology and function.
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Affiliation(s)
- Roberto Ferrari
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, 43124 Parma, Italy;
| | - Nicole Grandi
- Laboratory of Molecular Virology, Department of Life and Environmental Sciences, University of Cagliari, Cittadella Universitaria di Monserrato, 09042 Monserrato, Italy; (N.G.); (E.T.)
| | - Enzo Tramontano
- Laboratory of Molecular Virology, Department of Life and Environmental Sciences, University of Cagliari, Cittadella Universitaria di Monserrato, 09042 Monserrato, Italy; (N.G.); (E.T.)
- Istituto di Ricerca Genetica e Biomedica, Consiglio Nazionale delle Ricerche, 09042 Monserrato, Italy
| | - Giorgio Dieci
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, 43124 Parma, Italy;
- Correspondence:
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Mo D, Li X, Raabe CA, Rozhdestvensky TS, Skryabin BV, Brosius J. Circular RNA Encoded Amyloid Beta peptides-A Novel Putative Player in Alzheimer's Disease. Cells 2020; 9:E2196. [PMID: 33003364 PMCID: PMC7650678 DOI: 10.3390/cells9102196] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 09/15/2020] [Accepted: 09/24/2020] [Indexed: 02/05/2023] Open
Abstract
Alzheimer's disease (AD) is an age-related detrimental dementia. Amyloid beta peptides (Aβ) play a crucial role in the pathology of AD. In familial AD, Aβ are generated from the full-length amyloid beta precursor protein (APP) via dysregulated proteolytic processing; however, in the case of sporadic AD, the mechanism of Aβ biogenesis remains elusive. circRNAs are a class of transcripts preferentially expressed in brain. We identified a circRNA harboring the Aβ-coding region of the APP gene termed circAβ-a. This circular RNA was detected in the brains of AD patients and non-dementia controls. With the aid of our recently established approach for analysis of circRNA functions, we demonstrated that circAβ-a is efficiently translated into a novel Aβ-containing Aβ175 polypeptide (19.2 KDa) in both cultured cells and human brain. Furthermore, Aβ175 was shown to be processed into Aβ peptides-a hallmark of AD. In summary, our analysis revealed an alternative pathway of Aβ biogenesis. Consequently, circAβ-a and its corresponding translation product could potentially represent novel therapeutic targets for AD treatment. Importantly, our data point to yet another evolutionary route for potentially increasing proteome complexity by generating additional polypeptide variants using back-splicing of primary transcripts that yield circular RNA templates.
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Affiliation(s)
- Dingding Mo
- Max Planck Institute for Biology of Ageing, Joseph-Stelzmann-Strasse 9b, 50931 Cologne, Germany;
- VIB-KU Leuven Center for Brain & Disease Research, KU Leuven, O&N IV Herestraat 49—box 602, 3000 Leuven, Belgium
- Medical Faculty, Core Facility Transgenic Animal and Genetic Engineering Models (TRAM), University of Münster, Von-Esmarch-Str. 56, D-48149 Münster, Germany; (T.S.R.); (B.V.S.)
| | - Xinping Li
- Max Planck Institute for Biology of Ageing, Joseph-Stelzmann-Strasse 9b, 50931 Cologne, Germany;
| | - Carsten A. Raabe
- Institute of Experimental Pathology, Centre for Molecular Biology of Inflammation (ZMBE), University of Münster, Von-Esmarch-Str. 56, D-48149 Münster, Germany; (C.A.R.); (J.B.)
- Institute of Medical Biochemistry, Centre for Molecular Biology of Inflammation (ZMBE), University of Münster, Von-Esmarch-Strasse 56, D-48149 Münster, Germany
| | - Timofey S. Rozhdestvensky
- Medical Faculty, Core Facility Transgenic Animal and Genetic Engineering Models (TRAM), University of Münster, Von-Esmarch-Str. 56, D-48149 Münster, Germany; (T.S.R.); (B.V.S.)
| | - Boris V. Skryabin
- Medical Faculty, Core Facility Transgenic Animal and Genetic Engineering Models (TRAM), University of Münster, Von-Esmarch-Str. 56, D-48149 Münster, Germany; (T.S.R.); (B.V.S.)
| | - Juergen Brosius
- Institute of Experimental Pathology, Centre for Molecular Biology of Inflammation (ZMBE), University of Münster, Von-Esmarch-Str. 56, D-48149 Münster, Germany; (C.A.R.); (J.B.)
- Institutes for Systems Genetics, Frontiers Science Center for Disease-related Molecular Network, West China Hospital, Sichuan University, Chengdu 610212, China
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Nishihara H. Transposable elements as genetic accelerators of evolution: contribution to genome size, gene regulatory network rewiring and morphological innovation. Genes Genet Syst 2020; 94:269-281. [PMID: 31932541 DOI: 10.1266/ggs.19-00029] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
In the current era, as a growing number of genome sequence assemblies have been reported in animals, an in-depth analysis of transposable elements (TEs) is one of the most fundamental and essential studies for evolutionary genomics. Although TEs have, in general, been regarded as non-functional junk/selfish DNA, parasitic elements or harmful mutagens, studies have revealed that TEs have had a substantial and sometimes beneficial impact on host genomes in several ways. First, TEs are themselves diverse and thus provide lineage-specific characteristics to the genomes. Second, because TEs constitute a substantial fraction of animal genomes, they are a major contributing factor to evolutionary changes in genome size and composition. Third, host organisms have co-opted many repetitive sequences as genes, cis-regulatory elements and chromatin domain boundaries, which alter gene regulatory networks and in addition are partly involved in morphological evolution, as has been well documented in mammals. Here, I review the impact of TEs on various aspects of the genome, such as genome size and diversity in animals, as well as the evolution of gene networks and genome architecture in mammals. Given that a number of TE families probably remain to be discovered in many non-model organisms, unknown TEs may have contributed to gene networks in a much wider variety of animals than considered previously.
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Exaptation at the molecular genetic level. SCIENCE CHINA-LIFE SCIENCES 2018; 62:437-452. [PMID: 30798493 DOI: 10.1007/s11427-018-9447-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2018] [Accepted: 12/01/2018] [Indexed: 12/22/2022]
Abstract
The realization that body parts of animals and plants can be recruited or coopted for novel functions dates back to, or even predates the observations of Darwin. S.J. Gould and E.S. Vrba recognized a mode of evolution of characters that differs from adaptation. The umbrella term aptation was supplemented with the concept of exaptation. Unlike adaptations, which are restricted to features built by selection for their current role, exaptations are features that currently enhance fitness, even though their present role was not a result of natural selection. Exaptations can also arise from nonaptations; these are characters which had previously been evolving neutrally. All nonaptations are potential exaptations. The concept of exaptation was expanded to the molecular genetic level which aided greatly in understanding the enormous potential of neutrally evolving repetitive DNA-including transposed elements, formerly considered junk DNA-for the evolution of genes and genomes. The distinction between adaptations and exaptations is outlined in this review and examples are given. Also elaborated on is the fact that such distinctions are sometimes more difficult to determine; this is a widespread phenomenon in biology, where continua abound and clear borders between states and definitions are rare.
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Komseli ES, Pateras IS, Krejsgaard T, Stawiski K, Rizou SV, Polyzos A, Roumelioti FM, Chiourea M, Mourkioti I, Paparouna E, Zampetidis CP, Gumeni S, Trougakos IP, Pefani DE, O’Neill E, Gagos S, Eliopoulos AG, Fendler W, Chowdhury D, Bartek J, Gorgoulis VG. A prototypical non-malignant epithelial model to study genome dynamics and concurrently monitor micro-RNAs and proteins in situ during oncogene-induced senescence. BMC Genomics 2018; 19:37. [PMID: 29321003 PMCID: PMC5763532 DOI: 10.1186/s12864-017-4375-1] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Accepted: 12/11/2017] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Senescence is a fundamental biological process implicated in various pathologies, including cancer. Regarding carcinogenesis, senescence signifies, at least in its initial phases, an anti-tumor response that needs to be circumvented for cancer to progress. Micro-RNAs, a subclass of regulatory, non-coding RNAs, participate in senescence regulation. At the subcellular level micro-RNAs, similar to proteins, have been shown to traffic between organelles influencing cellular behavior. The differential function of micro-RNAs relative to their subcellular localization and their role in senescence biology raises concurrent in situ analysis of coding and non-coding gene products in senescent cells as a necessity. However, technical challenges have rendered in situ co-detection unfeasible until now. METHODS In the present report we describe a methodology that bypasses these technical limitations achieving for the first time simultaneous detection of both a micro-RNA and a protein in the biological context of cellular senescence, utilizing the new commercially available SenTraGorTM compound. The method was applied in a prototypical human non-malignant epithelial model of oncogene-induced senescence that we generated for the purposes of the study. For the characterization of this novel system, we applied a wide range of cellular and molecular techniques, as well as high-throughput analysis of the transcriptome and micro-RNAs. RESULTS This experimental setting has three advantages that are presented and discussed: i) it covers a "gap" in the molecular carcinogenesis field, as almost all corresponding in vitro models are fibroblast-based, even though the majority of neoplasms have epithelial origin, ii) it recapitulates the precancerous and cancerous phases of epithelial tumorigenesis within a short time frame under the light of natural selection and iii) it uses as an oncogenic signal, the replication licensing factor CDC6, implicated in both DNA replication and transcription when over-expressed, a characteristic that can be exploited to monitor RNA dynamics. CONCLUSIONS Consequently, we demonstrate that our model is optimal for studying the molecular basis of epithelial carcinogenesis shedding light on the tumor-initiating events. The latter may reveal novel molecular targets with clinical benefit. Besides, since this method can be incorporated in a wide range of low, medium or high-throughput image-based approaches, we expect it to be broadly applicable.
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Affiliation(s)
- Eirini-Stavroula Komseli
- Molecular Carcinogenesis Group, Department of Histology and Embryology, School of Medicine, National & Kapodistrian University of Athens, 75 Mikras Asias St, GR-11527 Athens, Greece
| | - Ioannis S. Pateras
- Molecular Carcinogenesis Group, Department of Histology and Embryology, School of Medicine, National & Kapodistrian University of Athens, 75 Mikras Asias St, GR-11527 Athens, Greece
| | - Thorbjørn Krejsgaard
- Department of Immunology and Microbiology, University of Copenhagen, Blegdamsvej 3c, DK-2200 Copenhagen, Denmark
| | - Konrad Stawiski
- Department of Biostatistics and Translational Medicine, Medical University of Lodz, 15 Mazowiecka St. 92-215, Lodz, Poland
| | - Sophia V. Rizou
- Molecular Carcinogenesis Group, Department of Histology and Embryology, School of Medicine, National & Kapodistrian University of Athens, 75 Mikras Asias St, GR-11527 Athens, Greece
| | - Alexander Polyzos
- Biomedical Research Foundation of the Academy of Athens, 4 Soranou Ephessiou St, GR-11527 Athens, Greece
| | - Fani-Marlen Roumelioti
- Biomedical Research Foundation of the Academy of Athens, 4 Soranou Ephessiou St, GR-11527 Athens, Greece
| | - Maria Chiourea
- Biomedical Research Foundation of the Academy of Athens, 4 Soranou Ephessiou St, GR-11527 Athens, Greece
| | - Ioanna Mourkioti
- Molecular Carcinogenesis Group, Department of Histology and Embryology, School of Medicine, National & Kapodistrian University of Athens, 75 Mikras Asias St, GR-11527 Athens, Greece
| | - Eleni Paparouna
- Molecular Carcinogenesis Group, Department of Histology and Embryology, School of Medicine, National & Kapodistrian University of Athens, 75 Mikras Asias St, GR-11527 Athens, Greece
| | - Christos P. Zampetidis
- Molecular Carcinogenesis Group, Department of Histology and Embryology, School of Medicine, National & Kapodistrian University of Athens, 75 Mikras Asias St, GR-11527 Athens, Greece
| | - Sentiljana Gumeni
- Department of Cell Biology and Biophysics, Faculty of Biology, National & Kapodistrian University of Athens, GR-15784 Athens, Greece
| | - Ioannis P. Trougakos
- Department of Cell Biology and Biophysics, Faculty of Biology, National & Kapodistrian University of Athens, GR-15784 Athens, Greece
| | - Dafni-Eleftheria Pefani
- CRUK/MRC Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, OX3 7DQ UK
| | - Eric O’Neill
- CRUK/MRC Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, OX3 7DQ UK
| | - Sarantis Gagos
- Biomedical Research Foundation of the Academy of Athens, 4 Soranou Ephessiou St, GR-11527 Athens, Greece
| | - Aristides G. Eliopoulos
- Department of Biology, School of Medicine, National & Kapodistrian University of Athens, 75 Mikras Asias St, GR-11527 Athens, Greece
- Institute of Molecular Biology and Biotechnology, Foundation for Research & Technology-Hellas, GR-70013 Heraklion, Crete Greece
| | - Wojciech Fendler
- Department of Biostatistics and Translational Medicine, Medical University of Lodz, 15 Mazowiecka St. 92-215, Lodz, Poland
- Department of Radiation Oncology, Dana-Farber Cancer Institute, 450 Brookline Ave, Boston, MA 02215 USA
| | - Dipanjan Chowdhury
- Department of Radiation Oncology, Dana-Farber Cancer Institute, 450 Brookline Ave, Boston, MA 02215 USA
- Harvard Medical School, 25 Shattuck St, Boston, MA 02115 USA
| | - Jiri Bartek
- Genome Integrity Unit, Danish Cancer Society Research Centre, Strandboulevarden 49, DK-2100 Copenhagen, Denmark
- Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacky University, Hněvotínská, 1333/5, 779 00 Olomouc, Czech Republic
- Department of Medical Biochemistry and Biophysics, Karolinska Institute, Science for Life Laboratory, Division of Translational Medicine and Chemical Biology, SE-171 77 Stockholm, Sweden
| | - Vassilis G. Gorgoulis
- Molecular Carcinogenesis Group, Department of Histology and Embryology, School of Medicine, National & Kapodistrian University of Athens, 75 Mikras Asias St, GR-11527 Athens, Greece
- Biomedical Research Foundation of the Academy of Athens, 4 Soranou Ephessiou St, GR-11527 Athens, Greece
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Wilmslow Road, Manchester, M20 4QL UK
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Iacoangeli A, Dosunmu A, Eom T, Stefanov DG, Tiedge H. Regulatory BC1 RNA in cognitive control. ACTA ACUST UNITED AC 2017; 24:267-277. [PMID: 28620074 PMCID: PMC5473108 DOI: 10.1101/lm.045427.117] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Accepted: 04/12/2017] [Indexed: 12/27/2022]
Abstract
Dendritic regulatory BC1 RNA is a non-protein-coding (npc) RNA that operates in the translational control of gene expression. The absence of BC1 RNA in BC1 knockout (KO) animals causes translational dysregulation that entails neuronal phenotypic alterations including prolonged epileptiform discharges, audiogenic seizure activity in vivo, and excessive cortical oscillations in the γ frequency band. Here we asked whether BC1 RNA control is also required for higher brain functions such as learning, memory, or cognition. To address this question, we used odor/object attentional set shifting tasks in which prefrontal cortical performance was assessed in a series of discrimination and conflict learning sessions. Results obtained in these behavioral trials indicate that BC1 KO animals were significantly impaired in their cognitive flexibility. When faced with conflicting information sources, BC1 KO animals committed regressive errors as they were compromised in their ability to disengage from recently acquired memories even though recall of such memories was in conflict with new situational context. The observed cognitive deficits are reminiscent of those previously described in subtypes of human autism spectrum disorders.
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Affiliation(s)
- Anna Iacoangeli
- The Robert F. Furchgott Center for Neural and Behavioral Science, State University of New York Downstate Medical Center, Brooklyn, New York 11203, USA.,Department of Physiology and Pharmacology, State University of New York Downstate Medical Center, Brooklyn, New York 11203, USA
| | - Aderemi Dosunmu
- The Robert F. Furchgott Center for Neural and Behavioral Science, State University of New York Downstate Medical Center, Brooklyn, New York 11203, USA.,Department of Physiology and Pharmacology, State University of New York Downstate Medical Center, Brooklyn, New York 11203, USA
| | - Taesun Eom
- The Robert F. Furchgott Center for Neural and Behavioral Science, State University of New York Downstate Medical Center, Brooklyn, New York 11203, USA.,Department of Physiology and Pharmacology, State University of New York Downstate Medical Center, Brooklyn, New York 11203, USA
| | - Dimitre G Stefanov
- Statistical Design and Analysis, Research Division, State University of New York Downstate Medical Center, Brooklyn, New York 11203, USA
| | - Henri Tiedge
- The Robert F. Furchgott Center for Neural and Behavioral Science, State University of New York Downstate Medical Center, Brooklyn, New York 11203, USA .,Department of Physiology and Pharmacology, State University of New York Downstate Medical Center, Brooklyn, New York 11203, USA.,Department of Neurology, State University of New York Downstate Medical Center, Brooklyn, New York 11203, USA
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BC1 RNA motifs required for dendritic transport in vivo. Sci Rep 2016; 6:28300. [PMID: 27350115 PMCID: PMC4923876 DOI: 10.1038/srep28300] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Accepted: 05/20/2016] [Indexed: 12/26/2022] Open
Abstract
BC1 RNA is a small brain specific non-protein coding RNA. It is transported from the cell body into dendrites where it is involved in the fine-tuning translational control. Due to its compactness and established secondary structure, BC1 RNA is an ideal model for investigating the motifs necessary for dendritic localization. Previously, microinjection of in vitro transcribed BC1 RNA mutants into the soma of cultured primary neurons suggested the importance of RNA motifs for dendritic targeting. These ex vivo experiments identified a single bulged nucleotide (U22) and a putative K-turn (GA motif) structure required for dendritic localization or distal transport, respectively. We generated six transgenic mouse lines (three founders each) containing neuronally expressing BC1 RNA variants on a BC1 RNA knockout mouse background. In contrast to ex vivo data, we did not find indications of reduction or abolition of dendritic BC1 RNA localization in the mutants devoid of the GA motif or the bulged nucleotide. We confirmed the ex vivo data, which showed that the triloop terminal sequence had no consequence on dendritic transport. Interestingly, changing the triloop supporting structure completely abolished dendritic localization of BC1 RNA. We propose a novel RNA motif important for dendritic transport in vivo.
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Raabe CA, Brosius J. Does every transcript originate from a gene? Ann N Y Acad Sci 2015; 1341:136-48. [PMID: 25847549 DOI: 10.1111/nyas.12741] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Revised: 02/05/2015] [Accepted: 02/11/2015] [Indexed: 12/20/2022]
Abstract
Outdated gene definitions favored regions corresponding to mature messenger RNAs, in particular, the open reading frame. In eukaryotes, the intergenic space was widely regarded nonfunctional and devoid of RNA transcription. Original concepts were based on the assumption that RNA expression was restricted to known protein-coding genes and a few so-called structural RNA genes, such as ribosomal RNAs or transfer RNAs. With the discovery of introns and, more recently, sensitive techniques for monitoring genome-wide transcription, this view had to be substantially modified. Tiling microarrays and RNA deep sequencing revealed myriads of transcripts, which cover almost entire genomes. The tremendous complexity of non-protein-coding RNA transcription has to be integrated into novel gene definitions. Despite an ever-growing list of functional RNAs, questions concerning the mass of identified transcripts are under dispute. Here, we examined genome-wide transcription from various angles, including evolutionary considerations, and suggest, in analogy to novel alternative splice variants that do not persist, that the vast majority of transcripts represent raw material for potential, albeit rare, exaptation events.
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Affiliation(s)
- Carsten A Raabe
- Institute of Experimental Pathology, ZMBE, University of Münster, Münster, Germany
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Abstract
Manfred Eigen extended Erwin Schroedinger's concept of "life is physics and chemistry" through the introduction of information theory and cybernetic systems theory into "life is physics and chemistry and information." Based on this assumption, Eigen developed the concepts of quasispecies and hypercycles, which have been dominant in molecular biology and virology ever since. He insisted that the genetic code is not just used metaphorically: it represents a real natural language. However, the basics of scientific knowledge changed dramatically within the second half of the 20th century. Unfortunately, Eigen ignored the results of the philosophy of science discourse on essential features of natural languages and codes: a natural language or code emerges from populations of living agents that communicate. This contribution will look at some of the highlights of this historical development and the results relevant for biological theories about life.
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