1
|
Brown JC, McMichael BD, Vandadi V, Mukherjee A, Salzler HR, Matera AG. Lysine-36 of Drosophila histone H3.3 supports adult longevity. G3 (BETHESDA, MD.) 2024; 14:jkae030. [PMID: 38366796 PMCID: PMC10989886 DOI: 10.1093/g3journal/jkae030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Revised: 01/16/2023] [Accepted: 02/04/2024] [Indexed: 02/18/2024]
Abstract
Aging is a multifactorial process that disturbs homeostasis, increases disease susceptibility, and ultimately results in death. Although the definitive set of molecular mechanisms responsible for aging remain to be discovered, epigenetic change over time is proving to be a promising piece of the puzzle. Several post-translational histone modifications have been linked to the maintenance of longevity. Here, we focus on lysine-36 of the replication-independent histone protein, H3.3 (H3.3K36). To interrogate the role of this residue in Drosophila developmental gene regulation, we generated a lysine-to-arginine mutant that blocks the activity of its cognate-modifying enzymes. We found that an H3.3BK36R mutation causes a significant reduction in adult lifespan, accompanied by dysregulation of the genomic and transcriptomic architecture. Transgenic co-expression of wild-type H3.3B completely rescues the longevity defect. Because H3.3 is known to accumulate in nondividing tissues, we carried out transcriptome profiling of young vs aged adult fly heads. The data show that loss of H3.3K36 results in age-dependent misexpression of NF-κB and other innate immune target genes, as well as defects in silencing of heterochromatin. We propose H3.3K36 maintains the postmitotic epigenomic landscape, supporting longevity by regulating both pericentric and telomeric retrotransposons and by suppressing aberrant immune signaling.
Collapse
Affiliation(s)
- John C Brown
- Integrative Program for Biological and Genome Sciences, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Benjamin D McMichael
- Integrative Program for Biological and Genome Sciences, University of North Carolina, Chapel Hill, NC 27599, USA
- Department of Biology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Vasudha Vandadi
- Integrative Program for Biological and Genome Sciences, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Aadit Mukherjee
- Department of Biology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Harmony R Salzler
- Integrative Program for Biological and Genome Sciences, University of North Carolina, Chapel Hill, NC 27599, USA
| | - A Gregory Matera
- Integrative Program for Biological and Genome Sciences, University of North Carolina, Chapel Hill, NC 27599, USA
- Department of Biology, University of North Carolina, Chapel Hill, NC 27599, USA
- Department of Genetics, University of North Carolina, Chapel Hill, NC 27599, USA
- RNA Discovery Center, Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC 27599, USA
| |
Collapse
|
2
|
Brown JC, McMichael BD, Vandadi V, Mukherjee A, Salzler HR, Matera AG. Lysine-36 of Drosophila histone H3.3 supports adult longevity. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.28.559962. [PMID: 38196611 PMCID: PMC10775331 DOI: 10.1101/2023.09.28.559962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2024]
Abstract
Aging is a multifactorial process that disturbs homeostasis, increases disease susceptibility, and ultimately results in death. Although the definitive set of molecular mechanisms responsible for aging remain to be discovered, epigenetic change over time is proving to be a promising piece of the puzzle. Several posttranslational histone modifications (PTMs) have been linked to the maintenance of longevity. Here, we focus on lysine-36 of the replication-independent histone protein, H3.3 (H3.3K36). To interrogate the role of this residue in Drosophila developmental gene regulation, we generated a lysine to arginine mutant that blocks the activity of its cognate modifying enzymes. We found that an H3.3BK36R mutation causes a significant reduction in adult lifespan, accompanied by dysregulation of the genomic and transcriptomic architecture. Transgenic co-expression of wild-type H3.3B completely rescues the longevity defect. Because H3.3 is known to accumulate in non-dividing tissues, we carried out transcriptome profiling of young vs aged adult fly heads. The data show that loss of H3.3K36 results in age-dependent misexpression of NF-κB and other innate immune target genes, as well as defects in silencing of heterochromatin. We propose H3.3K36 maintains the postmitotic epigenomic landscape, supporting longevity by regulating both pericentric and telomeric retrotransposons and by suppressing aberrant immune signaling.
Collapse
Affiliation(s)
- John C. Brown
- Integrative Program for Biological and Genome Sciences, University of North Carolina, Chapel Hill, NC, USA
| | - Benjamin D. McMichael
- Integrative Program for Biological and Genome Sciences, University of North Carolina, Chapel Hill, NC, USA
- Department of Biology, University of North Carolina, Chapel Hill, NC, USA
| | - Vasudha Vandadi
- Integrative Program for Biological and Genome Sciences, University of North Carolina, Chapel Hill, NC, USA
| | - Aadit Mukherjee
- Department of Biology, University of North Carolina, Chapel Hill, NC, USA
| | - Harmony R. Salzler
- Integrative Program for Biological and Genome Sciences, University of North Carolina, Chapel Hill, NC, USA
| | - A. Gregory Matera
- Integrative Program for Biological and Genome Sciences, University of North Carolina, Chapel Hill, NC, USA
- Department of Biology, University of North Carolina, Chapel Hill, NC, USA
- Department of Genetics, University of North Carolina, Chapel Hill, NC, USA
- RNA Discovery Center, Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC, USA
| |
Collapse
|
3
|
Melnikova L, Golovnin A. Multiple Roles of dXNP and dADD1- Drosophila Orthologs of ATRX Chromatin Remodeler. Int J Mol Sci 2023; 24:16486. [PMID: 38003676 PMCID: PMC10671109 DOI: 10.3390/ijms242216486] [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: 10/09/2023] [Revised: 11/11/2023] [Accepted: 11/16/2023] [Indexed: 11/26/2023] Open
Abstract
The Drosophila melanogaster dADD1 and dXNP proteins are orthologues of the ADD and SNF2 domains of the vertebrate ATRX (Alpha-Thalassemia with mental Retardation X-related) protein. ATRX plays a role in general molecular processes, such as regulating chromatin status and gene expression, while dADD1 and dXNP have similar functions in the Drosophila genome. Both ATRX and dADD1/dXNP interact with various protein partners and participate in various regulatory complexes. Disruption of ATRX expression in humans leads to the development of α-thalassemia and cancer, especially glioma. However, the mechanisms that allow ATRX to regulate various cellular processes are poorly understood. Studying the functioning of dADD1/dXNP in the Drosophila model may contribute to understanding the mechanisms underlying the multifunctional action of ATRX and its connection with various cellular processes. This review provides a brief overview of the currently available information in mammals and Drosophila regarding the roles of ATRX, dXNP, and dADD1. It discusses possible mechanisms of action of complexes involving these proteins.
Collapse
Affiliation(s)
- Larisa Melnikova
- Department of Drosophila Molecular Genetics, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., 119334 Moscow, Russia
| | - Anton Golovnin
- Department of Drosophila Molecular Genetics, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., 119334 Moscow, Russia
| |
Collapse
|
4
|
Albig C, Wang C, Dann GP, Wojcik F, Schauer T, Krause S, Maenner S, Cai W, Li Y, Girton J, Muir TW, Johansen J, Johansen KM, Becker PB, Regnard C. JASPer controls interphase histone H3S10 phosphorylation by chromosomal kinase JIL-1 in Drosophila. Nat Commun 2019; 10:5343. [PMID: 31767855 PMCID: PMC6877644 DOI: 10.1038/s41467-019-13174-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Accepted: 10/22/2019] [Indexed: 01/02/2023] Open
Abstract
In flies, the chromosomal kinase JIL-1 is responsible for most interphase histone H3S10 phosphorylation and has been proposed to protect active chromatin from acquiring heterochromatic marks, such as dimethylated histone H3K9 (H3K9me2) and HP1. Here, we show that JIL-1's targeting to chromatin depends on a PWWP domain-containing protein JASPer (JIL-1 Anchoring and Stabilizing Protein). JASPer-JIL-1 (JJ)-complex is the major form of kinase in vivo and is targeted to active genes and telomeric transposons via binding of the PWWP domain of JASPer to H3K36me3 nucleosomes, to modulate transcriptional output. JIL-1 and JJ-complex depletion in cycling cells lead to small changes in H3K9me2 distribution at active genes and telomeric transposons. Finally, we identify interactors of the endogenous JJ-complex and propose that JIL-1 not only prevents heterochromatin formation but also coordinates chromatin-based regulation in the transcribed part of the genome.
Collapse
Affiliation(s)
- Christian Albig
- Molecular Biology Division, Biomedical Center, Faculty of Medicine and Center for Integrated Protein Science Munich (CIPSM), LMU Munich, 82152, Martinsried, Germany
- Graduate School for Quantitative Biosciences (QBM), LMU Munich, 81377, Munich, Germany
| | - Chao Wang
- Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, IA, 50011, USA
| | - Geoffrey P Dann
- Department of Chemistry, Frick Laboratory, Princeton University, Princeton, NJ, 08544, USA
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Felix Wojcik
- Department of Chemistry, Frick Laboratory, Princeton University, Princeton, NJ, 08544, USA
| | - Tamás Schauer
- Bioinformatics Unit, Biomedical Center, Faculty of Medicine, LMU Munich, 82152, Martinsried, Germany
| | - Silke Krause
- Molecular Biology Division, Biomedical Center, Faculty of Medicine and Center for Integrated Protein Science Munich (CIPSM), LMU Munich, 82152, Martinsried, Germany
| | - Sylvain Maenner
- Molecular Biology Division, Biomedical Center, Faculty of Medicine and Center for Integrated Protein Science Munich (CIPSM), LMU Munich, 82152, Martinsried, Germany
- UMR7365 CNRS-UL, IMoPA, University of Lorraine, 54505, Vandoeuvre-lès-Nancy, France
| | - Weili Cai
- Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, IA, 50011, USA
| | - Yeran Li
- Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, IA, 50011, USA
| | - Jack Girton
- Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, IA, 50011, USA
| | - Tom W Muir
- Department of Chemistry, Frick Laboratory, Princeton University, Princeton, NJ, 08544, USA
| | - Jørgen Johansen
- Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, IA, 50011, USA
| | - Kristen M Johansen
- Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, IA, 50011, USA
| | - Peter B Becker
- Molecular Biology Division, Biomedical Center, Faculty of Medicine and Center for Integrated Protein Science Munich (CIPSM), LMU Munich, 82152, Martinsried, Germany.
| | - Catherine Regnard
- Molecular Biology Division, Biomedical Center, Faculty of Medicine and Center for Integrated Protein Science Munich (CIPSM), LMU Munich, 82152, Martinsried, Germany.
| |
Collapse
|
5
|
Radion E, Morgunova V, Ryazansky S, Akulenko N, Lavrov S, Abramov Y, Komarov PA, Glukhov SI, Olovnikov I, Kalmykova A. Key role of piRNAs in telomeric chromatin maintenance and telomere nuclear positioning in Drosophila germline. Epigenetics Chromatin 2018; 11:40. [PMID: 30001204 PMCID: PMC6043984 DOI: 10.1186/s13072-018-0210-4] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Accepted: 07/06/2018] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Telomeric small RNAs related to PIWI-interacting RNAs (piRNAs) have been described in various eukaryotes; however, their role in germline-specific telomere function remains poorly understood. Using a Drosophila model, we performed an in-depth study of the biogenesis of telomeric piRNAs and their function in telomere homeostasis in the germline. RESULTS To fully characterize telomeric piRNA clusters, we integrated the data obtained from analysis of endogenous telomeric repeats, as well as transgenes inserted into different telomeric and subtelomeric regions. The small RNA-seq data from strains carrying telomeric transgenes demonstrated that all transgenes belong to a class of dual-strand piRNA clusters; however, their capacity to produce piRNAs varies significantly. Rhino, a paralog of heterochromatic protein 1 (HP1) expressed exclusively in the germline, is associated with all telomeric transgenes, but its enrichment correlates with the abundance of transgenic piRNAs. It is likely that this heterogeneity is determined by the sequence peculiarities of telomeric retrotransposons. In contrast to the heterochromatic non-telomeric germline piRNA clusters, piRNA loss leads to a dramatic decrease in HP1, Rhino, and trimethylated histone H3 lysine 9 in telomeric regions. Therefore, the presence of piRNAs is required for the maintenance of telomere chromatin in the germline. Moreover, piRNA loss causes telomere translocation from the nuclear periphery toward the nuclear interior but does not affect telomere end capping. Analysis of the telomere-associated sequences (TASs) chromatin revealed strong tissue specificity. In the germline, TASs are enriched with HP1 and Rhino, in contrast to somatic tissues, where they are repressed by Polycomb group proteins. CONCLUSIONS piRNAs play an essential role in the assembly of telomeric chromatin, as well as in nuclear telomere positioning in the germline. Telomeric arrays and TASs belong to a unique type of Rhino-dependent piRNA clusters with transcripts that serve simultaneously as piRNA precursors and as their only targets. Telomeric chromatin is highly sensitive to piRNA loss, implying the existence of a novel developmental checkpoint that depends on telomere integrity in the germline.
Collapse
Affiliation(s)
- Elizaveta Radion
- Institute of Molecular Genetics, Russian Academy of Sciences, Kurchatov sq. 2, Moscow, Russia, 123182
| | - Valeriya Morgunova
- Institute of Molecular Genetics, Russian Academy of Sciences, Kurchatov sq. 2, Moscow, Russia, 123182
| | - Sergei Ryazansky
- Institute of Molecular Genetics, Russian Academy of Sciences, Kurchatov sq. 2, Moscow, Russia, 123182
| | - Natalia Akulenko
- Institute of Molecular Genetics, Russian Academy of Sciences, Kurchatov sq. 2, Moscow, Russia, 123182
| | - Sergey Lavrov
- Institute of Molecular Genetics, Russian Academy of Sciences, Kurchatov sq. 2, Moscow, Russia, 123182
| | - Yuri Abramov
- Institute of Molecular Genetics, Russian Academy of Sciences, Kurchatov sq. 2, Moscow, Russia, 123182
| | - Pavel A Komarov
- Institute of Molecular Genetics, Russian Academy of Sciences, Kurchatov sq. 2, Moscow, Russia, 123182.,Department of Biochemistry, Faculty of Biology, Lomonosov Moscow State University, Moscow, Russia, 119991
| | - Sergey I Glukhov
- Institute of Molecular Genetics, Russian Academy of Sciences, Kurchatov sq. 2, Moscow, Russia, 123182
| | - Ivan Olovnikov
- Institute of Molecular Genetics, Russian Academy of Sciences, Kurchatov sq. 2, Moscow, Russia, 123182
| | - Alla Kalmykova
- Institute of Molecular Genetics, Russian Academy of Sciences, Kurchatov sq. 2, Moscow, Russia, 123182.
| |
Collapse
|
6
|
Asif-Laidin A, Delmarre V, Laurentie J, Miller WJ, Ronsseray S, Teysset L. Short and long-term evolutionary dynamics of subtelomeric piRNA clusters in Drosophila. DNA Res 2017; 24:459-472. [PMID: 28459978 PMCID: PMC5737368 DOI: 10.1093/dnares/dsx017] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2016] [Accepted: 03/29/2017] [Indexed: 12/31/2022] Open
Abstract
Two Telomeric Associated Sequences, TAS-R and TAS-L, form the principal subtelomeric repeat families identified in Drosophila melanogaster. They are PIWI-interacting RNA (piRNA) clusters involved in repression of Transposable Elements. In this study, we revisited TAS structural and functional dynamics in D. melanogaster and in related species. In silico analysis revealed that TAS-R family members are composed of previously uncharacterized domains. This analysis also showed that TAS-L repeats are composed of arrays of a region we have named "TAS-L like" (TLL) identified specifically in one TAS-R family member, X-TAS. TLL were also present in other species of the melanogaster subgroup. Therefore, it is possible that TLL represents an ancestral subtelomeric piRNA core-cluster. Furthermore, all D. melanogaster genomes tested possessed at least one TAS-R locus, whereas TAS-L can be absent. A screen of 110 D. melanogaster lines showed that X-TAS is always present in flies living in the wild, but often absent in long-term laboratory stocks and that natural populations frequently lost their X-TAS within 2 years upon lab conditioning. Therefore, the unexpected structural and temporal dynamics of subtelomeric piRNA clusters demonstrated here suggests that genome organization is subjected to distinct selective pressures in the wild and upon domestication in the laboratory.
Collapse
Affiliation(s)
- Amna Asif-Laidin
- Sorbonne Universités, UPMC University of Paris 06, CNRS, Biologie du Développement Paris-Seine, Institut de Biologie Paris-Seine (LBD-IBPS), 75005 Paris, France
| | - Valérie Delmarre
- Sorbonne Universités, UPMC University of Paris 06, CNRS, Biologie du Développement Paris-Seine, Institut de Biologie Paris-Seine (LBD-IBPS), 75005 Paris, France
| | - Jeanne Laurentie
- Sorbonne Universités, UPMC University of Paris 06, CNRS, Biologie du Développement Paris-Seine, Institut de Biologie Paris-Seine (LBD-IBPS), 75005 Paris, France
| | - Wolfgang J. Miller
- Lab Genome Dynamics, Department for Cell & Developmental Biology, Center of Anatomy and Cell Biology, Medical University of Vienna, A-1090 Vienna, Austria
| | - Stéphane Ronsseray
- Sorbonne Universités, UPMC University of Paris 06, CNRS, Biologie du Développement Paris-Seine, Institut de Biologie Paris-Seine (LBD-IBPS), 75005 Paris, France
| | - Laure Teysset
- Sorbonne Universités, UPMC University of Paris 06, CNRS, Biologie du Développement Paris-Seine, Institut de Biologie Paris-Seine (LBD-IBPS), 75005 Paris, France
| |
Collapse
|
7
|
Drosophila: Retrotransposons Making up Telomeres. Viruses 2017; 9:v9070192. [PMID: 28753967 PMCID: PMC5537684 DOI: 10.3390/v9070192] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Revised: 07/14/2017] [Accepted: 07/17/2017] [Indexed: 12/27/2022] Open
Abstract
Drosophila and extant species are the best-studied telomerase exception. In this organism, telomere elongation is coupled with targeted retrotransposition of Healing Transposon (HeT-A) and Telomere Associated Retrotransposon (TART) with sporadic additions of Telomere Associated and HeT-A Related (TAHRE), all three specialized non-Long Terminal Repeat (non-LTR) retrotransposons. These three very special retroelements transpose in head to tail arrays, always in the same orientation at the end of the chromosomes but never in interior locations. Apparently, retrotransposon and telomerase telomeres might seem very different, but a detailed view of their mechanisms reveals similarities explaining how the loss of telomerase in a Drosophila ancestor could successfully have been replaced by the telomere retrotransposons. In this review, we will discover that although HeT-A, TART, and TAHRE are still the only examples to date where their targeted transposition is perfectly tamed into the telomere biology of Drosophila, there are other examples of retrotransposons that manage to successfully integrate inside and at the end of telomeres. Because the aim of this special issue is viral integration at telomeres, understanding the base of the telomerase exceptions will help to obtain clues on similar strategies that mobile elements and viruses could have acquired in order to ensure their survival in the host genome.
Collapse
|
8
|
Abstract
Although most of non-long terminal repeat (non-LTR) retrotransposons are incorporated in the host genome almost randomly, some non-LTR retrotransposons are incorporated into specific sequences within a target site. On the basis of structural and phylogenetic features, non-LTR retrotransposons are classified into two large groups, restriction enzyme-like endonuclease (RLE)-encoding elements and apurinic/apyrimidinic endonuclease (APE)-encoding elements. All clades of RLE-encoding non-LTR retrotransposons include site-specific elements. However, only two of more than 20 APE-encoding clades, Tx1 and R1, contain site-specific non-LTR elements. Site-specific non-LTR retrotransposons usually target within multi-copy RNA genes, such as rRNA gene (rDNA) clusters, or repetitive genomic sequences, such as telomeric repeats; this behavior may be a symbiotic strategy to reduce the damage to the host genome. Site- and sequence-specificity are variable even among closely related non-LTR elements and appeared to have changed during evolution. In the APE-encoding elements, the primary determinant of the sequence- specific integration is APE itself, which nicks one strand of the target DNA during the initiation of target primed reverse transcription (TPRT). However, other factors, such as interaction between mRNA and the target DNA, and access to the target region in the nuclei also affect the sequence-specificity. In contrast, in the RLE-encoding elements, DNA-binding motifs appear to affect their sequence-specificity, rather than the RLE domain itself. Highly specific integration properties of these site-specific non-LTR elements make them ideal alternative tools for sequence-specific gene delivery, particularly for therapeutic purposes in human diseases.
Collapse
|
9
|
Specific Localization of the Drosophila Telomere Transposon Proteins and RNAs, Give Insight in Their Behavior, Control and Telomere Biology in This Organism. PLoS One 2015; 10:e0128573. [PMID: 26068215 PMCID: PMC4467039 DOI: 10.1371/journal.pone.0128573] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Accepted: 04/28/2015] [Indexed: 01/02/2023] Open
Abstract
Drosophila telomeres constitute a remarkable exception to the telomerase mechanism. Although maintaining the same cytological and functional properties as telomerase maintain telomeres, Drosophila telomeres embed the telomere retrotransposons whose specific and highly regulated terminal transposition maintains the appropriate telomere length in this organism. Nevertheless, our current understanding of how the mechanism of the retrotransposon telomere works and which features are shared with the telomerase system is very limited. We report for the first time a detailed study of the localization of the main components that constitute the telomeres in Drosophila, HeT-A and TART RNAs and proteins. Our results in wild type and mutant strains reveal localizations of HeT-A Gag and TART Pol that give insight in the behavior of the telomere retrotransposons and their control. We find that TART Pol and HeT-A Gag only co-localize at the telomeres during the interphase of cells undergoing mitotic cycles. In addition, unexpected protein and RNA localizations with a well-defined pattern in cells such as the ovarian border cells and nurse cells, suggest possible strategies for the telomere transposons to reach the oocyte, and/or additional functions that might be important for the correct development of the organism. Finally, we have been able to visualize the telomere RNAs at different ovarian stages of development in wild type and mutant lines, demonstrating their presence in spite of being tightly regulated by the piRNA mechanism.
Collapse
|