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Moldovan JB, Kopera HC, Liu Y, Garcia-Canadas M, Catalina P, Leone P, Sanchez L, Kitzman J, Kidd J, Garcia-Perez J, Moran J. Variable patterns of retrotransposition in different HeLa strains provide mechanistic insights into SINE RNA mobilization processes. Nucleic Acids Res 2024; 52:7761-7779. [PMID: 38850156 PMCID: PMC11260458 DOI: 10.1093/nar/gkae448] [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: 02/16/2024] [Revised: 05/08/2024] [Accepted: 05/14/2024] [Indexed: 06/10/2024] Open
Abstract
Alu elements are non-autonomous Short INterspersed Elements (SINEs) derived from the 7SL RNA gene that are present at over one million copies in human genomic DNA. Alu mobilizes by a mechanism known as retrotransposition, which requires the Long INterspersed Element-1 (LINE-1) ORF2-encoded protein (ORF2p). Here, we demonstrate that HeLa strains differ in their capacity to support Alu retrotransposition. Human Alu elements retrotranspose efficiently in HeLa-HA and HeLa-CCL2 (Alu-permissive) strains, but not in HeLa-JVM or HeLa-H1 (Alu-nonpermissive) strains. A similar pattern of retrotransposition was observed for other 7SL RNA-derived SINEs and tRNA-derived SINEs. In contrast, mammalian LINE-1s, a zebrafish LINE, a human SINE-VNTR-Alu (SVA) element, and an L1 ORF1-containing mRNA can retrotranspose in all four HeLa strains. Using an in vitro reverse transcriptase-based assay, we show that Alu RNAs associate with ORF2p and are converted into cDNAs in both Alu-permissive and Alu-nonpermissive HeLa strains, suggesting that 7SL- and tRNA-derived SINEs use strategies to 'hijack' L1 ORF2p that are distinct from those used by SVA elements and ORF1-containing mRNAs. These data further suggest ORF2p associates with the Alu RNA poly(A) tract in both Alu-permissive and Alu-nonpermissive HeLa strains, but that Alu retrotransposition is blocked after this critical step in Alu-nonpermissive HeLa strains.
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Affiliation(s)
- John B Moldovan
- Department of Human Genetics, University of Michigan, Ann Arbor, MI 48109, USA
| | - Huira C Kopera
- Department of Human Genetics, University of Michigan, Ann Arbor, MI 48109, USA
| | - Ying Liu
- Department of Human Genetics, University of Michigan, Ann Arbor, MI 48109, USA
| | - Marta Garcia-Canadas
- Department of Genomic Medicine, GENYO, Centre for Genomics and Oncological Research, Pfizer-University of Granada-Andalusian Regional Government, PTS Granada 18016, Spain
| | | | - Paola E Leone
- Genetics and Genomics Laboratory, SOLCA Hospital, Quito, Ecuador
| | - Laura Sanchez
- Department of Genomic Medicine, GENYO, Centre for Genomics and Oncological Research, Pfizer-University of Granada-Andalusian Regional Government, PTS Granada 18016, Spain
| | - Jacob O Kitzman
- Department of Human Genetics, University of Michigan, Ann Arbor, MI 48109, USA
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI 48109, USA
| | - Jeffrey M Kidd
- Department of Human Genetics, University of Michigan, Ann Arbor, MI 48109, USA
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI 48109, USA
| | - Jose Luis Garcia-Perez
- Department of Genomic Medicine, GENYO, Centre for Genomics and Oncological Research, Pfizer-University of Granada-Andalusian Regional Government, PTS Granada 18016, Spain
| | - John V Moran
- Department of Human Genetics, University of Michigan, Ann Arbor, MI 48109, USA
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48109, USA
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2
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Moldovan JB, Kopera HC, Liu Y, Garcia-Canadas M, Catalina P, Leone PE, Sanchez L, Kitzman JO, Kidd JM, Garcia-Perez JL, Moran JV. Variable patterns of retrotransposition in different HeLa strains provide mechanistic insights into SINE RNA mobilization processes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.03.592410. [PMID: 38746229 PMCID: PMC11092746 DOI: 10.1101/2024.05.03.592410] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
Alu elements are non-autonomous Short INterspersed Elements (SINEs) derived from the 7SL RNA gene that are present at over one million copies in human genomic DNA. Alu mobilizes by a mechanism known as retrotransposition, which requires the Long INterspersed Element-1 (LINE-1 or L1) ORF2 -encoded protein (ORF2p). Here, we demonstrate that HeLa strains differ in their capacity to support Alu retrotransposition. Human Alu elements retrotranspose efficiently in HeLa-HA and HeLa-CCL2 ( Alu -permissive) strains, but not in HeLa-JVM or HeLa-H1 ( Alu -nonpermissive) strains. A similar pattern of retrotransposition was observed for other 7SL RNA -derived SINEs and tRNA -derived SINEs. In contrast, mammalian LINE-1s, a zebrafish LINE, a human SINE-VNTR - Alu ( SVA ) element, and an L1 ORF1 -containing messenger RNA can retrotranspose in all four HeLa strains. Using an in vitro reverse transcriptase-based assay, we show that Alu RNAs associate with ORF2p and are converted into cDNAs in both Alu -permissive and Alu -nonpermissive HeLa strains, suggesting that 7SL - and tRNA -derived SINE RNAs use strategies to 'hijack' L1 ORF2p that are distinct from those used by SVA elements and ORF1 -containing mRNAs. These data further suggest ORF2p associates with the Alu RNA poly(A) tract in both Alu -permissive and Alu -nonpermissive HeLa strains, but that Alu retrotransposition is blocked after this critical step in Alu -nonpermissive HeLa strains.
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3
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Sobočan N, Himelreich-Perić M, Katušić-Bojanac A, Krasić J, Sinčić N, Majić Ž, Jurić-Lekić G, Šerman L, Marić A, Ježek D, Bulić-Jakuš F. Extended Prophylactic Effect of N-tert-Butyl-α-phenylnitron against Oxidative/Nitrosative Damage Caused by the DNA-Hypomethylating Drug 5-Azacytidine in the Rat Placenta. Int J Mol Sci 2022; 23:603. [PMID: 35054786 PMCID: PMC8775603 DOI: 10.3390/ijms23020603] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 01/02/2022] [Accepted: 01/04/2022] [Indexed: 12/10/2022] Open
Abstract
Antioxidant N-tert-Butyl-α-phenylnitron (PBN) partly protected embryos from the negative effects of a DNA demethylating drug 5-azacytidine during pregnancy. Our aim was to investigate PBN's impact on the placenta. Fischer rat dams were treated on gestation days (GD) 12 and 13 by PBN (40 mg/kg), followed by 5azaC (5 mg/kg) after one hour. Global methylation was assessed by pyrosequencing. Numerical density was calculated from immunohistochemical expression in single cells for proliferating (PCNA), oxidative (oxoguanosine) and nitrosative (nitrotyrosine) activity. Results were compared with the PBN-treated and control rats. PBN-pretreatment significantly increased placental weight at GD15 and GD20, diminished by 5azaC, and diminished apoptosis in GD 20 placentas caused by 5azaC. Oxoguanosine expression in placentas of 5azaC-treated dams was especially high in the placental labyrinth on GD 15, while PBN-pretreatment lowered its expression on GD 15 and GD 20 in both the labyrinth and basal layer. 5azaC enhanced nitrotyrosine level in the labyrinth of both gestational stages, while PBN-pretreatment lowered it. We conclude that PBN exerted its prophylactic activity against DNA hypomethylating agent 5azaC in the placenta through free radical scavenging, especially in the labyrinthine part of the placenta until the last day of pregnancy.
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Affiliation(s)
- Nikola Sobočan
- Scientific Centre of Excellence for Reproductive and Regenerative Medicine, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia; (N.S.); (A.K.-B.); (J.K.); (N.S.); (G.J.-L.); (L.Š.); (D.J.); (F.B.-J.)
- Department of Gastroenterology, University Hospital Merkur, 10000 Zagreb, Croatia
| | - Marta Himelreich-Perić
- Scientific Centre of Excellence for Reproductive and Regenerative Medicine, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia; (N.S.); (A.K.-B.); (J.K.); (N.S.); (G.J.-L.); (L.Š.); (D.J.); (F.B.-J.)
- Department of Biology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia;
| | - Ana Katušić-Bojanac
- Scientific Centre of Excellence for Reproductive and Regenerative Medicine, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia; (N.S.); (A.K.-B.); (J.K.); (N.S.); (G.J.-L.); (L.Š.); (D.J.); (F.B.-J.)
- Department of Biology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia;
| | - Jure Krasić
- Scientific Centre of Excellence for Reproductive and Regenerative Medicine, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia; (N.S.); (A.K.-B.); (J.K.); (N.S.); (G.J.-L.); (L.Š.); (D.J.); (F.B.-J.)
- Department of Biology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia;
| | - Nino Sinčić
- Scientific Centre of Excellence for Reproductive and Regenerative Medicine, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia; (N.S.); (A.K.-B.); (J.K.); (N.S.); (G.J.-L.); (L.Š.); (D.J.); (F.B.-J.)
- Department of Biology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia;
| | - Željka Majić
- Department of Biology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia;
| | - Gordana Jurić-Lekić
- Scientific Centre of Excellence for Reproductive and Regenerative Medicine, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia; (N.S.); (A.K.-B.); (J.K.); (N.S.); (G.J.-L.); (L.Š.); (D.J.); (F.B.-J.)
- Department of Histology and Embryology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia
| | - Ljiljana Šerman
- Scientific Centre of Excellence for Reproductive and Regenerative Medicine, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia; (N.S.); (A.K.-B.); (J.K.); (N.S.); (G.J.-L.); (L.Š.); (D.J.); (F.B.-J.)
- Department of Biology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia;
| | - Andreja Marić
- Department of Internal Medicine, County Hospital Čakovec, 40000 Čakovec, Croatia;
| | - Davor Ježek
- Scientific Centre of Excellence for Reproductive and Regenerative Medicine, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia; (N.S.); (A.K.-B.); (J.K.); (N.S.); (G.J.-L.); (L.Š.); (D.J.); (F.B.-J.)
- Department of Histology and Embryology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia
| | - Floriana Bulić-Jakuš
- Scientific Centre of Excellence for Reproductive and Regenerative Medicine, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia; (N.S.); (A.K.-B.); (J.K.); (N.S.); (G.J.-L.); (L.Š.); (D.J.); (F.B.-J.)
- Department of Biology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia;
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Cytoplasmic synthesis of endogenous Alu complementary DNA via reverse transcription and implications in age-related macular degeneration. Proc Natl Acad Sci U S A 2021; 118:2022751118. [PMID: 33526699 DOI: 10.1073/pnas.2022751118] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Alu retroelements propagate via retrotransposition by hijacking long interspersed nuclear element-1 (L1) reverse transcriptase (RT) and endonuclease activities. Reverse transcription of Alu RNA into complementary DNA (cDNA) is presumed to occur exclusively in the nucleus at the genomic integration site. Whether Alu cDNA is synthesized independently of genomic integration is unknown. Alu RNA promotes retinal pigmented epithelium (RPE) death in geographic atrophy, an untreatable type of age-related macular degeneration. We report that Alu RNA-induced RPE degeneration is mediated via cytoplasmic L1-reverse-transcribed Alu cDNA independently of retrotransposition. Alu RNA did not induce cDNA production or RPE degeneration in L1-inhibited animals or human cells. Alu reverse transcription can be initiated in the cytoplasm via self-priming of Alu RNA. In four health insurance databases, use of nucleoside RT inhibitors was associated with reduced risk of developing atrophic macular degeneration (pooled adjusted hazard ratio, 0.616; 95% confidence interval, 0.493-0.770), thus identifying inhibitors of this Alu replication cycle shunt as potential therapies for a major cause of blindness.
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Booy EP, Gussakovsky D, Choi T, McKenna SA. The noncoding RNA BC200 associates with polysomes to positively regulate mRNA translation in tumor cells. J Biol Chem 2020; 296:100036. [PMID: 33410401 PMCID: PMC7949042 DOI: 10.1074/jbc.ra120.015775] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Revised: 10/30/2020] [Accepted: 11/04/2020] [Indexed: 12/19/2022] Open
Abstract
BC200 is a noncoding RNA elevated in a broad spectrum of tumor cells that is critical for cell viability, invasion, and migration. Overexpression studies have implicated BC200 and the rodent analog BC1 as negative regulators of translation in both cell-based and in vitro translation assays. Although these studies are consistent, they have not been confirmed in knockdown studies and direct evidence for this function is lacking. Herein, we have demonstrated that BC200 knockdown is correlated with a decrease in global translation rates. As this conflicts with the hypothesis that BC200 is a translational suppressor, we overexpressed BC200 by transfection of in vitro transcribed RNA and transient expression from transfected plasmids. In this context BC200 suppressed translation; however, an innate immune response confounded the data. To overcome this, breast cancer cells stably overexpressing BC200 and various control RNAs were developed by selection for genomic incorporation of a plasmid coexpressing BC200 and the neomycin resistance gene. Stable overexpression of BC200 was associated with elevated translation levels in pooled stable cell lines and isolated single-cell clones. Cross-linking sucrose density gradient centrifugation demonstrated an association of BC200 and its reported binding partners SRP9/14, CSDE1, DHX36, and PABPC1 with both ribosomal subunits and polysomal RNA, an association not previously observed owing to the labile nature of the interactions. In summary, these data present a novel understanding of BC200 function as well as optimized methodology that has far reaching implications in the study of noncoding RNAs, particularly within the context of translational regulatory mechanisms.
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Affiliation(s)
- Evan P Booy
- Department of Chemistry, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Daniel Gussakovsky
- Department of Chemistry, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Taegi Choi
- Department of Chemistry, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Sean A McKenna
- Department of Chemistry, University of Manitoba, Winnipeg, Manitoba, Canada.
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Krestel H, Meier JC. RNA Editing and Retrotransposons in Neurology. Front Mol Neurosci 2018; 11:163. [PMID: 29875629 PMCID: PMC5974252 DOI: 10.3389/fnmol.2018.00163] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Accepted: 04/30/2018] [Indexed: 12/28/2022] Open
Abstract
Compared to sites in protein-coding sequences many more targets undergoing adenosine to inosine (A-to-I) RNA editing were discovered in non-coding regions of human cerebral transcripts, particularly in genetic transposable elements called retrotransposons. We review here the interaction mechanisms of RNA editing and retrotransposons and their impact on normal function and human neurological diseases. Exemplarily, A-to-I editing of retrotransposons embedded in protein-coding mRNAs can contribute to protein abundance and function via circular RNA formation, alternative splicing, and exonization or silencing of retrotransposons. Interactions leading to disease are not very well understood. We describe human diseases with involvement of the central nervous system including inborn errors of metabolism, neurodevelopmental disorders, neuroinflammatory and neurodegenerative and paroxysmal diseases, in which retrotransposons (Alu and/or L1 elements) appear to be causally involved in genetic rearrangements. Sole binding of single-stranded retrotransposon transcripts by RNA editing enzymes rather than enzymatic deamination may have a homeostatic effect on retrotransposon turnover. We also review evidence in support of the emerging pathophysiological function of A-to-I editing of retrotransposons in inflammation and its implication for different neurological diseases including amyotrophic lateral sclerosis, frontotemporal dementia, Alzheimer's and Parkinson's disease, and epilepsy.
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Affiliation(s)
- Heinz Krestel
- Department of Neurology, Bern University Hospital and University of Bern, Bern, Switzerland.,Department for BioMedical Research, Bern University Hospital and University of Bern, Bern, Switzerland
| | - Jochen C Meier
- Division Cell Physiology, Zoological Institute, Technical University Braunschweig, Braunschweig, Germany
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7
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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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Goldman A, Capoano CA, González-López E, Geisinger A. Identifier (ID) elements are not preferentially located to brain-specific genes: high ID element representation in other tissue-specific- and housekeeping genes of the rat. Gene 2013; 533:72-7. [PMID: 24125954 DOI: 10.1016/j.gene.2013.10.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2013] [Revised: 09/06/2013] [Accepted: 10/01/2013] [Indexed: 12/01/2022]
Abstract
BC1 is a short non-coding RNA from rodents, which is transcribed by RNA pol III. Its RNA is highly abundant in the brain, where it exerts a post-transcriptional regulatory role in dendrites. Upon transcription, retroposition and insertion, BC1 gives rise to a subclass of short interspersed repetitive sequences (SINEs) named identifier (ID) elements. IDs can become integrated inside non-coding regions of RNA pol II transcription units, and - although challenged by a couple of reports - their preferential location to brain-specific genes has been long proposed. Furthermore, an additional, cis-regulatory role in the control of brain-specific pol II-directed transcripts has been suggested for these sequences. In this work we used Northern blot and in silico analyses to examine IDs' location among pol II transcription units in different tissues, and in housekeeping genes. ID sequences appeared distributed in a similar fashion within tissue-specific hnRNA populations of the brain, testis and liver, and within housekeeping primary transcripts as well. Moreover, when the lengths of the unprocessed transcripts were considered, ID representation was higher in housekeeping ones. On the other hand, ID elements appeared similarly distributed among the different gene regions, with the obvious exclusion of those sequences where strict constraints for proper gene expression exist. Altogether, the widespread distribution of ID elements in all the analyzed genes - including housekeeping - and in all gene regions, suggests a random location, raising questions about the specific cis-regulatory role of those sequences.
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Affiliation(s)
- Andrés Goldman
- Departamento de Biología Molecular, Instituto de Investigaciones Biológicas Clemente Estable (IIBCE), Avda. Italia 3318, 11600 Montevideo, Uruguay.
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Dridi S. Alu mobile elements: from junk DNA to genomic gems. SCIENTIFICA 2012; 2012:545328. [PMID: 24278713 PMCID: PMC3820591 DOI: 10.6064/2012/545328] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/21/2012] [Accepted: 11/06/2012] [Indexed: 06/02/2023]
Abstract
Alus, the short interspersed repeated sequences (SINEs), are retrotransposons that litter the human genomes and have long been considered junk DNA. However, recent findings that these mobile elements are transcribed, both as distinct RNA polymerase III transcripts and as a part of RNA polymerase II transcripts, suggest biological functions and refute the notion that Alus are biologically unimportant. Indeed, Alu RNAs have been shown to control mRNA processing at several levels, to have complex regulatory functions such as transcriptional repression and modulating alternative splicing and to cause a host of human genetic diseases. Alu RNAs embedded in Pol II transcripts can promote evolution and proteome diversity, which further indicates that these mobile retroelements are in fact genomic gems rather than genomic junks.
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Affiliation(s)
- Sami Dridi
- Nutrition Research Institute, The University of North Carolina at Chapel Hill, 500 Laureate Way, Kannapolis, NC 28081, USA
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Srikanta D, Sen SK, Huang CT, Conlin EM, Rhodes RM, Batzer MA. An alternative pathway for Alu retrotransposition suggests a role in DNA double-strand break repair. Genomics 2008; 93:205-12. [PMID: 18951971 DOI: 10.1016/j.ygeno.2008.09.016] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2008] [Revised: 09/15/2008] [Accepted: 09/26/2008] [Indexed: 11/18/2022]
Abstract
The Alu family is a highly successful group of non-LTR retrotransposons ubiquitously found in primate genomes. Similar to the L1 retrotransposon family, Alu elements integrate primarily through an endonuclease-dependent mechanism termed target site-primed reverse transcription (TPRT). Recent studies have suggested that, in addition to TPRT, L1 elements occasionally utilize an alternative endonuclease-independent pathway for genomic integration. To determine whether an analogous mechanism exists for Alu elements, we have analyzed three publicly available primate genomes (human, chimpanzee and rhesus macaque) for endonuclease-independent recently integrated or lineage specific Alu insertions. We recovered twenty-three examples of such insertions and show that these insertions are recognizably different from classical TPRT-mediated Alu element integration. We suggest a role for this process in DNA double-strand break repair and present evidence to suggest its association with intra-chromosomal translocations, in-vitro RNA recombination (IVRR), and synthesis-dependent strand annealing (SDSA).
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Affiliation(s)
- Deepa Srikanta
- Department of Biological Sciences, Biological Computation and Visualization Center, Louisiana State University, Baton Rouge, LA 70803, USA
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11
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Johnson LJ, Brookfield JFY. A Test of the Master Gene Hypothesis for Interspersed Repetitive DNA Sequences. Mol Biol Evol 2005; 23:235-9. [PMID: 16221895 DOI: 10.1093/molbev/msj034] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Many families of interspersed repetitive DNA elements, including human Alu and LINE (Long Interspersed Element) elements, have been proposed to have accumulated through repeated copying from a single source locus: the "master gene." The extent to which a master gene model is applicable has implications for the origin, evolution, and function of such sequences. One repetitive element family for which a convincing case for a master gene has been made is the rodent ID (identifier) elements. Here we devise a new test of the master gene model and use it to show that mouse ID element sequences are not compatible with a strict master gene model. We suggest that a single master gene is rarely, if ever, likely to be responsible for the accumulation of any repeat family.
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Affiliation(s)
- Louise J Johnson
- Institute of Genetics, University of Nottingham, Queens Medical Centre, Nottingham, United Kingdom
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12
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Abstract
Elucidation of complete nucleotide sequence of the human has revealed that coding sequences that store the information needed to synthesize functional proteins, occupy only 2% of the genomic region. The remaining 98%, barring few regulatory sequences, has been referred to as non-functional or junk DNA and consists of many kinds of repeat elements. In fact, human genome is the most repeat rich genome sequenced so far, in which more than half of the region is occupied by such sequences. Determination of significance of these repeats in the human genome has become the focus of many studies all over the world, especially after genome sequencing did not reveal any significant difference in coding regions between lower eukaryotes and human. In this article, we have focused on Alu repeats that are primate specific elements with many interesting biological properties. Moreover, these are the repeats with highest copy number in the human genome. We have highlighted different facets of their interaction with the genome and changing paradigms regarding their role in genome organization.
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Affiliation(s)
- Deepak Grover
- Functional Genomics Unit, Institute of Genomics and Integrative Biology, Mall Road, Delhi, India
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Pélissier T, Bousquet-Antonelli C, Lavie L, Deragon JM. Synthesis and processing of tRNA-related SINE transcripts in Arabidopsis thaliana. Nucleic Acids Res 2004; 32:3957-66. [PMID: 15282328 PMCID: PMC506818 DOI: 10.1093/nar/gkh738] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Despite the ubiquitous distribution of tRNA-related short interspersed elements (SINEs) in eukaryotic species, very little is known about the synthesis and processing of their RNAs. In this work, we have characterized in detail the different RNA populations resulting from the expression of a tRNA-related SINE S1 founder copy in Arabidopsis thaliana. The main population is composed of poly(A)-ending (pa) SINE RNAs, while two minor populations correspond to full-length (fl) or poly(A) minus [small cytoplasmic (sc)] SINE RNAs. Part of the poly(A) minus RNAs is modified by 3'-terminal addition of C or CA nucleotides. All three RNA populations accumulate in the cytoplasm. Using a mutagenesis approach, we show that the poly(A) region and the 3' end unique region, present at the founder locus, are both important for the maturation and the steady-state accumulation of the different S1 RNA populations. The observation that primary SINE transcripts can be post-transcriptionally processed in vivo into a poly(A)-ending species introduces the possibility that this paRNA is used as a retroposition intermediate.
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MESH Headings
- 3' Untranslated Regions
- Arabidopsis/genetics
- Base Sequence
- Cytoplasm/metabolism
- Gene Expression Regulation, Plant
- Molecular Sequence Data
- Polyadenylation
- RNA Processing, Post-Transcriptional
- RNA, Plant/biosynthesis
- RNA, Plant/chemistry
- RNA, Plant/metabolism
- RNA, Transfer/biosynthesis
- RNA, Transfer/chemistry
- RNA, Transfer/metabolism
- Regulatory Sequences, Ribonucleic Acid
- Short Interspersed Nucleotide Elements
- Transcription, Genetic
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Affiliation(s)
- Thierry Pélissier
- CNRS UMR 6547 BIOMOVE and GDR 2157, Université Blaise Pascal Clermont-Ferrand II, 63177 Aubière Cedex, France
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Carter AB, Salem AH, Hedges DJ, Keegan CN, Kimball B, Walker JA, Watkins WS, Jorde LB, Batzer MA. Genome-wide analysis of the human Alu Yb-lineage. Hum Genomics 2004; 1:167-78. [PMID: 15588477 PMCID: PMC3525081 DOI: 10.1186/1479-7364-1-3-167] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2003] [Accepted: 12/10/2003] [Indexed: 11/10/2022] Open
Abstract
The Alu Yb-lineage is a 'young' primarily human-specific group of short interspersed element (SINE) subfamilies that have integrated throughout the human genome. In this study, we have computationally screened the draft sequence of the human genome for Alu Yb-lineage subfamily members present on autosomal chromosomes. A total of 1,733 Yb Alu subfamily members have integrated into human autosomes. The average ages of Yb-lineage subfamilies, Yb7, Yb8 and Yb9, are estimated as 4.81, 2.39 and 2.32 million years, respectively. In order to determine the contribution of the Alu Yb-lineage to human genomic diversity, 1,202 loci were analysed using polymerase chain reaction (PCR)-based assays, which amplify the genomic regions containing individual Yb-lineage subfamily members. Approximately 20 percent of the Yb-lineage Alu elements are polymorphic for insertion presence/absence in the human genome. Fewer than 0.5 percent of the Yb loci also demonstrate insertions at orthologous positions in non-human primate genomes. Genomic sequencing of these unusual loci demonstrates that each of the orthologous loci from non-human primate genomes contains older Y, Sg and Sx Alu family members that have been altered, through various mechanisms, into Yb8 sequences. These data suggest that Alu Yb-lineage subfamily members are largely restricted to the human genome. The high copy number, level of insertion polymorphism and estimated age indicate that members of the Alu Yb elements will be useful in a wide range of genetic analyses.
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Affiliation(s)
- Anthony B Carter
- Department of Biological Sciences, Biological Computation and Visualization Center, Louisiana State University, 202 Life Sciences Building, Baton Rouge, LA 70803, USA
| | - Abdel-Halim Salem
- Department of Biological Sciences, Biological Computation and Visualization Center, Louisiana State University, 202 Life Sciences Building, Baton Rouge, LA 70803, USA
- Department of Anatomy, Faculty of Medicine, Suez Canal University, Ismailia, Egypt
| | - Dale J Hedges
- Department of Biological Sciences, Biological Computation and Visualization Center, Louisiana State University, 202 Life Sciences Building, Baton Rouge, LA 70803, USA
| | - Catherine Nguyen Keegan
- Department of Pathology, Louisiana State University Health Sciences Center, 1901 Perdido Street, New Orleans, LA 70112, USA
| | - Beth Kimball
- Department of Pathology, Louisiana State University Health Sciences Center, 1901 Perdido Street, New Orleans, LA 70112, USA
| | - Jerilyn A Walker
- Department of Biological Sciences, Biological Computation and Visualization Center, Louisiana State University, 202 Life Sciences Building, Baton Rouge, LA 70803, USA
| | - W Scott Watkins
- Department of Human Genetics, University of Utah Health Sciences Center, Salt Lake City, UT 84112, USA
| | - Lynn B Jorde
- Department of Human Genetics, University of Utah Health Sciences Center, Salt Lake City, UT 84112, USA
| | - Mark A Batzer
- Department of Biological Sciences, Biological Computation and Visualization Center, Louisiana State University, 202 Life Sciences Building, Baton Rouge, LA 70803, USA
- Department of Pathology, Louisiana State University Health Sciences Center, 1901 Perdido Street, New Orleans, LA 70112, USA
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15
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Gilbert N, Bomar JM, Burmeister M, Moran JV. Characterization of a mutagenic B1 retrotransposon insertion in the jittery mouse. Hum Mutat 2004; 24:9-13. [PMID: 15221784 DOI: 10.1002/humu.20060] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
B1 elements are an abundant class of short interspersed elements (SINEs) in the mouse genome and mobilize by a process known as retrotransposition. Here, we report the characterization of a mutagenic B1 insertion into exon 4 of the Atcay gene, which was previously shown to be responsible for the jittery mouse. Mutations in the human ortholog of this gene, ATCAY, are responsible for Cayman ataxia. The B1 insertion is approximately 150-bp long, ends in a 45-50-bp polyadenylic acid (poly A) tail, is flanked by a perfect 13-bp target-site duplication, and is inserted into a sequence that resembles a LINE-1 endonuclease consensus cleavage site. Computational analysis indicates that the mutagenic insertion is most closely related to elements of the B1-C subfamily, and we have identified two possible progenitor B1 sequences on mouse chromosome 19. Together, these data demonstrate that B1 retrotransposition is ongoing in the mouse genome and is consistent with the hypothesis that the reverse transcriptase and endonuclease encoded by LINE-1 elements mediate B1 mobility.
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Affiliation(s)
- Nicolas Gilbert
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor, Michigan, USA.
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16
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Abstract
The eukaryotic genome has undergone a series of epidemics of amplification of mobile elements that have resulted in most eukaryotic genomes containing much more of this 'junk' DNA than actual coding DNA. The majority of these elements utilize an RNA intermediate and are termed retroelements. Most of these retroelements appear to amplify in evolutionary waves that insert in the genome and then gradually diverge. In humans, almost half of the genome is recognizably derived from retroelements, with the two elements that are currently actively amplifying, L1 and Alu, making up about 25% of the genome and contributing extensively to disease. The mechanisms of this amplification process are beginning to be understood, although there are still more questions than answers. Insertion of new retroelements may directly damage the genome, and the presence of multiple copies of these elements throughout the genome has longer-term influences on recombination events in the genome and more subtle influences on gene expression.
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Affiliation(s)
- Prescott L Deininger
- Tulane Cancer Center, Department of Environmental Health Sciences, Tulane University Health Sciences Center, New Orleans, Louisiana 70112, USA.
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17
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Abstract
During the past 65 million years, Alu elements have propagated to more than one million copies in primate genomes, which has resulted in the generation of a series of Alu subfamilies of different ages. Alu elements affect the genome in several ways, causing insertion mutations, recombination between elements, gene conversion and alterations in gene expression. Alu-insertion polymorphisms are a boon for the study of human population genetics and primate comparative genomics because they are neutral genetic markers of identical descent with known ancestral states.
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Affiliation(s)
- Mark A Batzer
- Department of Biological Sciences, Biological Computation and Visualization Center, Louisiana State University, 202 Life Sciences Building, Baton Rouge, Louisiana 70803, USA.
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18
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Muslimov IA, Lin Y, Heller M, Brosius J, Zakeri Z, Tiedge H. A small RNA in testis and brain: implications for male germ cell development. J Cell Sci 2002; 115:1243-50. [PMID: 11884523 DOI: 10.1242/jcs.115.6.1243] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
BC1 RNA, a small non-coding RNA polymerase III transcript, is selectively targeted to dendritic domains of a subset of neurons in the rodent nervous system. It has been implicated in the regulation of local protein synthesis in postsynaptic microdomains. The gene encoding BC1 RNA has been suggested to be a master gene for repetitive ID elements that are found interspersed throughout rodent genomes. A prerequisite for the generation of repetitive elements through retroposition and subsequent transmission in the germline is expression of the master gene RNA in germ cells. To test this hypothesis, we have investigated expression of BC1 RNA in murine male germ cells. We report that BC1 RNA is expressed at substantial levels in a subset of male germ cells. Results from cell fractionation experiments, developmental analysis,and northern and in situ hybridization showed that the RNA was expressed in pre-meiotic spermatogonia, with particularly high amounts in syncytial ensembles of cells that are primed for synchronous spermatogenic differentiation. BC1 RNA continued to be expressed in spermatocytes, but expression levels decreased during further spermatogenic development, and low or negligible amounts of BC1 RNA were identified in round and elongating spermatids. The combined data indicate that BC1 RNA operates in groups of interconnected germ cells, including spermatogonia, where it may function in the mediation of translational control. At the same time, the identification of BC1 RNA in germ cells provides essential support for the hypothesis that repetitive ID elements in rodent genomes arose from the BC1 RNA gene through retroposition.
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Affiliation(s)
- Ilham A Muslimov
- Department of Physiology and Pharmacology, State University of New York, Health Science Center at Brooklyn, Brooklyn, New York 11203, USA
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19
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Alemán C, Roy-Engel AM, Shaikh TH, Deininger PL. Cis-acting influences on Alu RNA levels. Nucleic Acids Res 2000; 28:4755-61. [PMID: 11095687 PMCID: PMC115182 DOI: 10.1093/nar/28.23.4755] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The human short interspersed repeated element (SINE), Alu, amplifies through a poorly understood RNA-mediated mechanism, termed retroposition. There are over one million copies of Alu per haploid human genome. The copies show some internal variations in sequence and are very heterogeneous in chromosomal environment. However, very few Alu elements actively amplify. The amplification rate has decreased greatly in the last 40 million years. Factors influencing Alu transcription would directly affect an element's retroposition capability. Therefore, we evaluated several features that might influence expression from individual Alu elements. The influence of various internal sequence variations and 3' unique flanks on full-length Alu RNA steady-state levels was determined. Alu subfamily diagnostic mutations do not significantly alter the amount of Alu RNA observed. However, sequences containing random mutations throughout the right half of selected genomic Alu elements altered Alu RNA steady-state levels in cultured cells. In addition, sequence variations at the 3' unique end of the transcript also significantly altered the Alu RNA levels. In general, sequence mutations and 3' end sequences contribute to Alu RNA levels, suggesting that the master Alu element(s) have a multitude of individual differences that collectively gives them a selective advantage over other Alu elements.
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Affiliation(s)
- C Alemán
- Tulane Cancer Center, SL-66, and Department of Environmental Health Sciences, Tulane University-Health Sciences Center, 1430 Tulane Avenue, New Orleans, LA 70112, USA
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20
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Rosén M, Edström J. DNA structures common for chironomid telomeres terminating with complex repeats. INSECT MOLECULAR BIOLOGY 2000; 9:341-347. [PMID: 10886419 DOI: 10.1046/j.1365-2583.2000.00193.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Tandem repeats, 340 bp long, have been shown to terminate the chromosomes in Chironomus pallidivittatus and similar DNA may be used for this purpose by related insects. In view of the importance of Chironomus in telomere studies, representing in principle a third system after short repeats and Drosophila telomeric retrotransposons, we have investigated the related Chironomus dilutus, to learn what DNA structures are conserved at the chromosome ends. Interspersed subrepeats in the telomeric repeats, which contain a long palindrome, and a zone of about 100 bp of relatively constant subtelomeric DNA towards the junction to the telomeric DNA, are characteristic for C. dilutus as for previously investigated species. C. dilutus has similar subtelomeric DNA at all chromosome ends, but typical telomeric repeats in only seven of the pairs since the eighth telocentric pair contains centromere-specific repeats.
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Affiliation(s)
- M Rosén
- Department of Genetics, Lund University, Lund, Sweden
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21
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Brosius J. RNAs from all categories generate retrosequences that may be exapted as novel genes or regulatory elements. Gene 1999; 238:115-34. [PMID: 10570990 DOI: 10.1016/s0378-1119(99)00227-9] [Citation(s) in RCA: 275] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
While the significance of middle repetitive elements had been neglected for a long time, there are again tendencies to ascribe most members of a given middle repetitive sequence family a functional role--as if the discussion of SINE (short interspersed repetitive elements) function only can occupy extreme positions. In this article, I argue that differences between the various classes of retrosequences concern mainly their copy numbers. Consequently, the function of SINEs should be viewed as pragmatic such as, for example, mRNA-derived retrosequences, without underestimating the impact of retroposition for generation of novel protein coding genes or parts thereof (exon shuffling by retroposition) and in particular of SINEs (and retroelements) in modulating genes and their expression. Rapid genomic change by accumulating retrosequences may even facilitate speciation [McDonald, J.F., 1995. Transposable elements: possible catalysts of organismic evolution. Trends Ecol. Evol. 10, 123-126.] In addition to providing mobile regulatory elements, small RNA-derived retrosequences including SINEs can, in analogy to mRNA-derived retrosequences, also give rise to novel small RNA genes. Perhaps not representative for all SINE/master gene relationships, we gained significant knowledge by studying the small neuronal non-messenger RNAs, namely BC1 RNA in rodents and BC200 RNA in primates. BC1 is the first identified master gene generating a subclass of ID repetitive elements, and BC200 is the only known Alu element (monomeric) that was exapted as a novel small RNA encoding gene.
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Affiliation(s)
- J Brosius
- Institute of Experimental Pathology/Molecular Neurobiology, ZMBE, University of Münster, Germany.
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22
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Abstract
Available data on possible genetic impacts of mammalian retroposons are reviewed. Most important is the growing number of established examples showing the involvement of retroposons in modulation of expression of protein-coding genes transcribed by RNA polymerase II (Pol II). Retroposons contain conserved blocks of nucleotide sequence for binding of some important Pol II transcription factors as well as sequences involved in regulation of stability of mRNA. Moreover, these mobile genes provide short regions of sequence homology for illegitimate recombinations, leading to diverse genome rearrangements during evolution. Therefore, mammalian retroposons representing a significant fraction of noncoding DNA cannot be considered at present as junk DNA but as important genetic symbionts driving the evolution of regulatory networks controlling gene expression.
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Affiliation(s)
- N V Tomilin
- Institute of Cytology, Russian Academy of Sciences, St. Petersburg, Russian Federation
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23
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Abstract
For hundreds of millions of years, perhaps from the very beginning of their evolutionary history, eukaryotic cells have been habitats and junkyards for countless generations of transposable elements, preserved in repetitive DNA sequences. Analysis of these sequences, combined with experimental research, reveals a history of complex 'intracellular ecosystems' of transposable elements that are inseparably associated with genomic evolution.
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Affiliation(s)
- J Jurka
- Genetic Information Research Institute, Sunnyvale, CA 94089, USA.
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24
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Taylor BA, Navin A, Skryabin BV, Brosius J. Localization of the mouse gene (Bc1) encoding neural BC1 RNA near the fibroblast growth factor 3 locus (Fgf3) on distal chromosome 7. Genomics 1997; 44:153-4. [PMID: 9286715 DOI: 10.1006/geno.1997.4840] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- B A Taylor
- Jackson Laboratory, Bar Harbor, Maine 04609, USA
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