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Adashev VE, Kotov AA, Bazylev SS, Kombarov IA, Olenkina OM, Shatskikh AS, Olenina LV. Essential functions of RNA helicase Vasa in maintaining germline stem cells and piRNA-guided Stellate silencing in Drosophila spermatogenesis. Front Cell Dev Biol 2024; 12:1450227. [PMID: 39184915 PMCID: PMC11341464 DOI: 10.3389/fcell.2024.1450227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2024] [Accepted: 07/29/2024] [Indexed: 08/27/2024] Open
Abstract
DEAD-box RNA helicase Vasa is required for gonad development and fertility in multiple animals. Vasa is implicated in many crucial aspects of Drosophila oogenesis, including translation regulation, primordial germ cell specification, piRNA silencing of transposable elements, and maintenance of germline stem cells (GSCs). However, data about Vasa functions in Drosophila spermatogenesis remain controversial. Here we showed that loss-of-function vasa mutations led to failures of GSC maintenance in the testes, a severe loss of total germ cell content, and a cessation of male fertility over time. Defects in GSC maintenance in vasa mutant testes were not associated with an increasing frequency of programmed cell death, indicating that a premature loss of GSCs occurred via entering differentiation. We found that Vasa is implicated in the positive regulation of rhino expression both in the testes and ovaries. The introduction of a transgene copy of rhino, encoding a nuclear component of piRNA pathway machinery, in vasa mutant background allowed us to restore premeiotic stages of spermatogenesis, including the maintenance of GSCs and the development of spermatogonia and spermatocytes. However, piRNA-guided repression of Stellate genes in spermatocytes of vasa mutant testes with additional rhino copy was not restored, and male fertility was disrupted. Our study uncovered a novel mechanistic link involving Vasa and Rhino in a regulatory network that mediates GSC maintenance but is dispensable for the perfect biogenesis of Su(Ste) piRNAs in testes. Thus, we have shown that Vasa functions in spermatogenesis are essential at two distinct developmental stages: in GSCs for their maintenance and in spermatocytes for piRNA-mediated silencing of Stellate genes.
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Affiliation(s)
- Vladimir E. Adashev
- Laboratory of Functional Genomics, Koltzov Institute of Developmental Biology, Russian Academy of Sciences, Moscow, Russia
| | - Alexei A. Kotov
- Laboratory of Functional Genomics, Koltzov Institute of Developmental Biology, Russian Academy of Sciences, Moscow, Russia
| | - Sergei S. Bazylev
- Laboratory of Functional Genomics, Koltzov Institute of Developmental Biology, Russian Academy of Sciences, Moscow, Russia
| | - Ilia A. Kombarov
- Laboratory of Functional Genomics, Koltzov Institute of Developmental Biology, Russian Academy of Sciences, Moscow, Russia
| | - Oxana M. Olenkina
- Department of Molecular Mechanisms for Realization of Genetic Information, National Research Centre Kurchatov Institute, Moscow, Russia
| | - Aleksei S. Shatskikh
- Laboratory of Functional Genomics, Koltzov Institute of Developmental Biology, Russian Academy of Sciences, Moscow, Russia
| | - Ludmila V. Olenina
- Laboratory of Functional Genomics, Koltzov Institute of Developmental Biology, Russian Academy of Sciences, Moscow, Russia
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2
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McQuarrie DWJ, Alizada A, Nicholson BC, Soller M. Rapid evolution of promoters from germline-specifically expressed genes including transposon silencing factors. BMC Genomics 2024; 25:678. [PMID: 38977960 PMCID: PMC11229233 DOI: 10.1186/s12864-024-10584-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2024] [Accepted: 07/01/2024] [Indexed: 07/10/2024] Open
Abstract
BACKGROUND The piRNA pathway in animal gonads functions as an 'RNA-based immune system', serving to silence transposable elements and prevent inheritance of novel invaders. In Drosophila, this pathway relies on three gonad-specific Argonaute proteins (Argonaute-3, Aubergine and Piwi) that associate with 23-28 nucleotide piRNAs, directing the silencing of transposon-derived transcripts. Transposons constitute a primary driver of genome evolution, yet the evolution of piRNA pathway factors has not received in-depth exploration. Specifically, channel nuclear pore proteins, which impact piRNA processing, exhibit regions of rapid evolution in their promoters. Consequently, the question arises whether such a mode of evolution is a general feature of transposon silencing pathways. RESULTS By employing genomic analysis of coding and promoter regions within genes that function in transposon silencing in Drosophila, we demonstrate that the promoters of germ cell-specific piRNA factors are undergoing rapid evolution. Our findings indicate that rapid promoter evolution is a common trait among piRNA factors engaged in germline silencing across insect species, potentially contributing to gene expression divergence in closely related taxa. Furthermore, we observe that the promoters of genes exclusively expressed in germ cells generally exhibit rapid evolution, with some divergence in gene expression. CONCLUSION Our results suggest that increased germline promoter evolution, in partnership with other factors, could contribute to transposon silencing and evolution of species through differential expression of genes driven by invading transposons.
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Affiliation(s)
- David W J McQuarrie
- School of Biosciences, College of Life and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
- Birmingham Centre for Genome Biology, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Azad Alizada
- Cancer Research UK Cambridge Institute, University of Cambridge, Li Ka Shing Centre, Cambridge, CB2 0RE, UK
| | - Benjamin Czech Nicholson
- Cancer Research UK Cambridge Institute, University of Cambridge, Li Ka Shing Centre, Cambridge, CB2 0RE, UK
| | - Matthias Soller
- School of Biosciences, College of Life and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.
- Birmingham Centre for Genome Biology, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.
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3
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Chen P, Pan KC, Park EH, Luo Y, Lee YCG, Aravin AA. Escalation of genome defense capacity enables control of an expanding meiotic driver. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.12.598716. [PMID: 38915551 PMCID: PMC11195268 DOI: 10.1101/2024.06.12.598716] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/26/2024]
Abstract
From RNA interference to chromatin silencing, diverse genome defense pathways silence selfish genetic elements to safeguard genome integrity1,2. Despite their diversity, different defense pathways share a modular organization, where numerous specificity factors identify diverse targets and common effectors silence them. In the PIWI-interacting RNA (piRNA) pathway, which controls selfish elements in the metazoan germline, diverse target RNAs are first identified by complementary base pairing with piRNAs and then silenced by PIWI-clade nucleases via enzymatic cleavage1,3. Such a binary architecture allows the defense systems to be readily adaptable, where new targets can be captured via the innovation of new specificity factors4,5. Thus, our current understanding of genome defense against lineage-specific selfish genes has been largely limited to the evolution of specificity factors, while it remains poorly understood whether other types of innovations are required. Here, we describe a new type of innovation, which escalates the defense capacity of the piRNA pathway to control a recently expanded selfish gene in Drosophila melanogaster. Through an in vivo RNAi screen for repressors of Stellate-a recently evolved and expanded selfish meiotic driver6-8-we discovered a novel defense factor, Trailblazer. Trailblazer is a transcription factor that promotes the expression of two PIWI-clade nucleases, Aub and AGO3, to match Stellate in abundance. Recent innovation in the DNA-binding domain of Trailblazer enabled it to drastically elevate Aub and AGO3 expression in the D. melanogaster lineage, thereby escalating the silencing capacity of the piRNA pathway to control expanded Stellate and safeguard fertility. As copy-number expansion is a recurrent feature of diverse selfish genes across the tree of life9-12, we envision that augmenting the defense capacity to quantitatively match selfish genes is likely a repeatedly employed defense strategy in evolution.
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Affiliation(s)
- Peiwei Chen
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California 91125, USA
| | - Katherine C. Pan
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California 91125, USA
| | - Eunice H. Park
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California 91125, USA
| | - Yicheng Luo
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California 91125, USA
| | - Yuh Chwen G. Lee
- Department of Ecology and Evolutionary Biology, University of California, Irvine, Irvine, California 92697, USA
| | - Alexei A. Aravin
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California 91125, USA
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4
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Ho S, Theurkauf W, Rice N. piRNA-Guided Transposon Silencing and Response to Stress in Drosophila Germline. Viruses 2024; 16:714. [PMID: 38793595 PMCID: PMC11125864 DOI: 10.3390/v16050714] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2024] [Revised: 04/23/2024] [Accepted: 04/27/2024] [Indexed: 05/26/2024] Open
Abstract
Transposons are integral genome constituents that can be domesticated for host functions, but they also represent a significant threat to genome stability. Transposon silencing is especially critical in the germline, which is dedicated to transmitting inherited genetic material. The small Piwi-interacting RNAs (piRNAs) have a deeply conserved function in transposon silencing in the germline. piRNA biogenesis and function are particularly well understood in Drosophila melanogaster, but some fundamental mechanisms remain elusive and there is growing evidence that the pathway is regulated in response to genotoxic and environmental stress. Here, we review transposon regulation by piRNAs and the piRNA pathway regulation in response to stress, focusing on the Drosophila female germline.
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Affiliation(s)
- Samantha Ho
- Program in Molecular Medicine, University Campus, University of Massachusetts Chan Medical School, Worcester, MA 01655, USA;
| | | | - Nicholas Rice
- Program in Molecular Medicine, University Campus, University of Massachusetts Chan Medical School, Worcester, MA 01655, USA;
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5
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Yushkova E. Interaction effect of mutations in the genes (piwi and aub) of the Argonaute family and hobo transposons on the integral survival parameters of Drosophila melanogaster. Biogerontology 2024; 25:131-146. [PMID: 37864608 DOI: 10.1007/s10522-023-10062-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Accepted: 08/03/2023] [Indexed: 10/23/2023]
Abstract
The Argonaute family genes (piwi and aub) involved in the production of small RNAs are responsible for the regulation of many cellular processes, including the suppression of genome instability, modulation of gene activity, and transposable elements. Dysfunction of these genes and the associated activation of transposable elements adversely affect reproductive development and quality of life. The role of transposons in contrast to retrotransposons and their interaction with genes of the Argonaute family in aging processes have not been studied. This study considers a scenario in which the piwi and aub genes in the presence of functional hobo transposons can modify the effects from the level of DNA damage to lifespan. The simultaneous presence of mutation (piwi or aub) and hobo (regardless of size) in the genome has practically no effect or (less often) leads to a decrease in the level of DNA damage in ovarian cells. A high level of sterility and low ovarian reserve were noted mainly with a combination of mutations and full-sized hobo elements. The combination of these two genetic factors negatively affects the fertility of young females and embryonic survival. Isolated cases of restoration of reproductive functions with age were noted but only in females that had low fertility in the early period of life. The presence of hobo transposons contributed to an increase in the lifespan of both mutant and non-mutant females. Dysfunction of the piwi and aub genes (without hobo) can reduce the lifespan of both sexes. Together, each mutation and hobo transposons act antagonistically/additively (in females) and synergistically/antagonistically (in males) to change the lifespan. In parameters of locus-specific instability, hobo activation was more pronounced in piwi gene dysfunction. The results obtained complement data on the study of new functions of Argonaute family genes and their interactions with transposable elements in the aging process.
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Affiliation(s)
- Elena Yushkova
- Institute of Biology Komi Science Centre of the Ural Branch of the Russian Academy of Sciences, 28 Kommunisticheskaya st., 167982, Syktyvkar, Komi Republic, Russia.
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6
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van Lopik J, Alizada A, Trapotsi MA, Hannon GJ, Bornelöv S, Czech Nicholson B. Unistrand piRNA clusters are an evolutionarily conserved mechanism to suppress endogenous retroviruses across the Drosophila genus. Nat Commun 2023; 14:7337. [PMID: 37957172 PMCID: PMC10643416 DOI: 10.1038/s41467-023-42787-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Accepted: 10/18/2023] [Indexed: 11/15/2023] Open
Abstract
The PIWI-interacting RNA (piRNA) pathway prevents endogenous genomic parasites, i.e. transposable elements, from damaging the genetic material of animal gonadal cells. Specific regions in the genome, called piRNA clusters, are thought to define each species' piRNA repertoire and therefore its capacity to recognize and silence specific transposon families. The unistrand cluster flamenco (flam) is essential in the somatic compartment of the Drosophila ovary to restrict Gypsy-family transposons from infecting the neighbouring germ cells. Disruption of flam results in transposon de-repression and sterility, yet it remains unknown whether this silencing mechanism is present more widely. Here, we systematically characterise 119 Drosophila species and identify five additional flam-like clusters separated by up to 45 million years of evolution. Small RNA-sequencing validated these as bona-fide unistrand piRNA clusters expressed in somatic cells of the ovary, where they selectively target transposons of the Gypsy family. Together, our study provides compelling evidence of a widely conserved transposon silencing mechanism that co-evolved with virus-like Gypsy-family transposons.
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Affiliation(s)
- Jasper van Lopik
- Cancer Research UK Cambridge Institute, University of Cambridge, Li Ka Shing Centre, Cambridge, CB2 0RE, UK
| | - Azad Alizada
- Cancer Research UK Cambridge Institute, University of Cambridge, Li Ka Shing Centre, Cambridge, CB2 0RE, UK
| | - Maria-Anna Trapotsi
- Cancer Research UK Cambridge Institute, University of Cambridge, Li Ka Shing Centre, Cambridge, CB2 0RE, UK
| | - Gregory J Hannon
- Cancer Research UK Cambridge Institute, University of Cambridge, Li Ka Shing Centre, Cambridge, CB2 0RE, UK
| | - Susanne Bornelöv
- Cancer Research UK Cambridge Institute, University of Cambridge, Li Ka Shing Centre, Cambridge, CB2 0RE, UK.
| | - Benjamin Czech Nicholson
- Cancer Research UK Cambridge Institute, University of Cambridge, Li Ka Shing Centre, Cambridge, CB2 0RE, UK.
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7
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Loubalova Z, Konstantinidou P, Haase AD. Themes and variations on piRNA-guided transposon control. Mob DNA 2023; 14:10. [PMID: 37660099 PMCID: PMC10474768 DOI: 10.1186/s13100-023-00298-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Accepted: 08/21/2023] [Indexed: 09/04/2023] Open
Abstract
PIWI-interacting RNAs (piRNAs) are responsible for preventing the movement of transposable elements in germ cells and protect the integrity of germline genomes. In this review, we examine the common elements of piRNA-guided silencing as well as the differences observed between species. We have categorized the mechanisms of piRNA biogenesis and function into modules. Individual PIWI proteins combine these modules in various ways to produce unique PIWI-piRNA pathways, which nevertheless possess the ability to perform conserved functions. This modular model incorporates conserved core mechanisms and accommodates variable co-factors. Adaptability is a hallmark of this RNA-based immune system. We believe that considering the differences in germ cell biology and resident transposons in different organisms is essential for placing the variations observed in piRNA biology into context, while still highlighting the conserved themes that underpin this process.
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Affiliation(s)
- Zuzana Loubalova
- National Institutes of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Parthena Konstantinidou
- National Institutes of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Astrid D Haase
- National Institutes of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA.
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8
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Iyer SS, Sun Y, Seyfferth J, Manjunath V, Samata M, Alexiadis A, Kulkarni T, Gutierrez N, Georgiev P, Shvedunova M, Akhtar A. The NSL complex is required for piRNA production from telomeric clusters. Life Sci Alliance 2023; 6:e202302194. [PMID: 37399316 PMCID: PMC10313855 DOI: 10.26508/lsa.202302194] [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: 05/31/2023] [Revised: 06/15/2023] [Accepted: 06/20/2023] [Indexed: 07/05/2023] Open
Abstract
The NSL complex is a transcriptional activator. Germline-specific knockdown of NSL complex subunits NSL1, NSL2, and NSL3 results in reduced piRNA production from a subset of bidirectional piRNA clusters, accompanied by widespread transposon derepression. The piRNAs most transcriptionally affected by NSL2 and NSL1 RNAi map to telomeric piRNA clusters. At the chromatin level, these piRNA clusters also show decreased levels of H3K9me3, HP1a, and Rhino after NSL2 depletion. Using NSL2 ChIP-seq in ovaries, we found that this protein specifically binds promoters of telomeric transposons HeT-A, TAHRE, and TART Germline-specific depletion of NSL2 also led to a reduction in nuclear Piwi in nurse cells. Our findings thereby support a role for the NSL complex in promoting the transcription of piRNA precursors from telomeric piRNA clusters and in regulating Piwi levels in the Drosophila female germline.
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Affiliation(s)
- Shantanu S Iyer
- Max Planck Institute of Immunobiology and Epigenetics, Freiburg im Breisgau, Germany
- Spemann Graduate School of Biology and Medicine (SGBM), University of Freiburg, Freiburg im Breisgau, Germany
- Faculty of Biology, University of Freiburg, Freiburg im Breisgau, Germany
| | - Yidan Sun
- Max Planck Institute of Immunobiology and Epigenetics, Freiburg im Breisgau, Germany
| | - Janine Seyfferth
- Max Planck Institute of Immunobiology and Epigenetics, Freiburg im Breisgau, Germany
| | - Vinitha Manjunath
- Max Planck Institute of Immunobiology and Epigenetics, Freiburg im Breisgau, Germany
| | - Maria Samata
- Max Planck Institute of Immunobiology and Epigenetics, Freiburg im Breisgau, Germany
| | - Anastasios Alexiadis
- Max Planck Institute of Immunobiology and Epigenetics, Freiburg im Breisgau, Germany
| | - Tanvi Kulkarni
- Max Planck Institute of Immunobiology and Epigenetics, Freiburg im Breisgau, Germany
| | - Noel Gutierrez
- Max Planck Institute of Immunobiology and Epigenetics, Freiburg im Breisgau, Germany
| | - Plamen Georgiev
- Max Planck Institute of Immunobiology and Epigenetics, Freiburg im Breisgau, Germany
| | - Maria Shvedunova
- Max Planck Institute of Immunobiology and Epigenetics, Freiburg im Breisgau, Germany
| | - Asifa Akhtar
- Max Planck Institute of Immunobiology and Epigenetics, Freiburg im Breisgau, Germany
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9
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Rocha JJ, Jayaram SA, Stevens TJ, Muschalik N, Shah RD, Emran S, Robles C, Freeman M, Munro S. Functional unknomics: Systematic screening of conserved genes of unknown function. PLoS Biol 2023; 21:e3002222. [PMID: 37552676 PMCID: PMC10409296 DOI: 10.1371/journal.pbio.3002222] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Accepted: 06/27/2023] [Indexed: 08/10/2023] Open
Abstract
The human genome encodes approximately 20,000 proteins, many still uncharacterised. It has become clear that scientific research tends to focus on well-studied proteins, leading to a concern that poorly understood genes are unjustifiably neglected. To address this, we have developed a publicly available and customisable "Unknome database" that ranks proteins based on how little is known about them. We applied RNA interference (RNAi) in Drosophila to 260 unknown genes that are conserved between flies and humans. Knockdown of some genes resulted in loss of viability, and functional screening of the rest revealed hits for fertility, development, locomotion, protein quality control, and resilience to stress. CRISPR/Cas9 gene disruption validated a component of Notch signalling and 2 genes contributing to male fertility. Our work illustrates the importance of poorly understood genes, provides a resource to accelerate future research, and highlights a need to support database curation to ensure that misannotation does not erode our awareness of our own ignorance.
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Affiliation(s)
- João J. Rocha
- MRC Laboratory of Molecular Biology, Cambridge, United Kingdom
| | | | - Tim J. Stevens
- MRC Laboratory of Molecular Biology, Cambridge, United Kingdom
| | | | - Rajen D. Shah
- Centre for Mathematical Sciences, University of Cambridge, Cambridge, United Kingdom
| | - Sahar Emran
- MRC Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Cristina Robles
- MRC Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Matthew Freeman
- MRC Laboratory of Molecular Biology, Cambridge, United Kingdom
- Sir William Dunn School of Pathology, University of Oxford, Oxford, United Kingdom
| | - Sean Munro
- MRC Laboratory of Molecular Biology, Cambridge, United Kingdom
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10
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Signor S, Vedanayagam J, Kim BY, Wierzbicki F, Kofler R, Lai EC. Rapid evolutionary diversification of the flamenco locus across simulans clade Drosophila species. PLoS Genet 2023; 19:e1010914. [PMID: 37643184 PMCID: PMC10495008 DOI: 10.1371/journal.pgen.1010914] [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: 03/07/2023] [Revised: 09/11/2023] [Accepted: 08/09/2023] [Indexed: 08/31/2023] Open
Abstract
Suppression of transposable elements (TEs) is paramount to maintain genomic integrity and organismal fitness. In D. melanogaster, the flamenco locus is a master suppressor of TEs, preventing the mobilization of certain endogenous retrovirus-like TEs from somatic ovarian support cells to the germline. It is transcribed by Pol II as a long (100s of kb), single-stranded, primary transcript, and metabolized into ~24-32 nt Piwi-interacting RNAs (piRNAs) that target active TEs via antisense complementarity. flamenco is thought to operate as a trap, owing to its high content of recent horizontally transferred TEs that are enriched in antisense orientation. Using newly-generated long read genome data, which is critical for accurate assembly of repetitive sequences, we find that flamenco has undergone radical transformations in sequence content and even copy number across simulans clade Drosophilid species. Drosophila simulans flamenco has duplicated and diverged, and neither copy exhibits synteny with D. melanogaster beyond the core promoter. Moreover, flamenco organization is highly variable across D. simulans individuals. Next, we find that D. simulans and D. mauritiana flamenco display signatures of a dual-stranded cluster, with ping-pong signals in the testis and/or embryo. This is accompanied by increased copy numbers of germline TEs, consistent with these regions operating as functional dual-stranded clusters. Overall, the physical and functional diversity of flamenco orthologs is testament to the extremely dynamic consequences of TE arms races on genome organization, not only amongst highly related species, but even amongst individuals.
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Affiliation(s)
- Sarah Signor
- Biological Sciences, North Dakota State University, Fargo, North Dakota, United States of America
| | - Jeffrey Vedanayagam
- Developmental Biology Program, Sloan-Kettering Institute, New York, New York, United States of America
- Department of Neuroscience, Developmental and Regenerative Biology, University of Texas at San Antonio, Texas, United States of America
| | - Bernard Y. Kim
- Department of Biology, Stanford University, Stanford, California, United States of America
| | - Filip Wierzbicki
- Institut für Populationsgenetik, Vetmeduni Vienna, Vienna, Austria
- Vienna Graduate School of Population Genetics, Vienna, Austria
| | - Robert Kofler
- Institut für Populationsgenetik, Vetmeduni Vienna, Vienna, Austria
| | - Eric C. Lai
- Developmental Biology Program, Sloan-Kettering Institute, New York, New York, United States of America
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11
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Adashev VE, Kotov AA, Olenina LV. RNA Helicase Vasa as a Multifunctional Conservative Regulator of Gametogenesis in Eukaryotes. Curr Issues Mol Biol 2023; 45:5677-5705. [PMID: 37504274 PMCID: PMC10378496 DOI: 10.3390/cimb45070358] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2023] [Revised: 06/30/2023] [Accepted: 07/03/2023] [Indexed: 07/29/2023] Open
Abstract
Being a conservative marker of germ cells across metazoan species, DEAD box RNA helicase Vasa (DDX4) remains the subject of worldwide investigations thanks to its multiple functional manifestations. Vasa takes part in the preformation of primordial germ cells in a group of organisms and contributes to the maintenance of germline stem cells. Vasa is an essential player in the piRNA-mediated silencing of harmful genomic elements and in the translational regulation of selected mRNAs. Vasa is the top hierarchical protein of germ granules, liquid droplet organelles that compartmentalize RNA processing factors. Here, we survey current advances and problems in the understanding of the multifaceted functions of Vasa proteins in the gametogenesis of different eukaryotic organisms, from nematodes to humans.
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Affiliation(s)
- Vladimir E Adashev
- Department of Molecular Mechanisms for Realization of Genetic Information, Laboratory of Biochemical Genetics of Animals, National Research Center "Kurchatov Institute", Kurchatov Sq. 1, 123182 Moscow, Russia
| | - Alexei A Kotov
- Department of Molecular Mechanisms for Realization of Genetic Information, Laboratory of Biochemical Genetics of Animals, National Research Center "Kurchatov Institute", Kurchatov Sq. 1, 123182 Moscow, Russia
| | - Ludmila V Olenina
- Department of Molecular Mechanisms for Realization of Genetic Information, Laboratory of Biochemical Genetics of Animals, National Research Center "Kurchatov Institute", Kurchatov Sq. 1, 123182 Moscow, Russia
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12
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Liang C, Li L, Zhao H, Lan M, Tang Y, Zhang M, Qin D, Wu G, Gao X. Identification and expression analysis of heat shock protein family genes of gall fly (Procecidochares utilis) under temperature stress. Cell Stress Chaperones 2023; 28:303-320. [PMID: 37071342 PMCID: PMC10167091 DOI: 10.1007/s12192-023-01338-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2022] [Revised: 03/18/2023] [Accepted: 03/21/2023] [Indexed: 04/19/2023] Open
Abstract
Heat shock proteins (HSP) are molecular chaperones involved in many normal cellular processes and environmental stresses. At the genome-wide level, there were no reports on the diversity and phylogeny of the heat shock protein family in Procecidochares utilis. In this study, 43 HSPs were identified from the genome of P. utilis, including 12 small heat shock proteins (sHSPs), 23 heat shock protein 40 (DNAJs), 6 heat shock protein 70 (HSP70s), and 2 heat shock protein 90 (HSP90s). The characteristics of these candidates HSP genes were analyzed by BLAST, and then phylogenetic analysis was carried out. Quantitative real-time PCR (qRT-PCR) was used to analyze the spatiotemporal expression patterns of sHSPs and HSP70s in P. utilis after temperature stress. Results showed that most sHSPs could be induced under heat stress during the adult stage of P. utilis, while a few HSP70s could be induced at the larval stage. This study provides an information framework for the HSP family of P. utilis. Moreover, it lays an important foundation for a better understanding of the role of HSP in the adaptability of P. utilis to various environments.
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Affiliation(s)
- Chen Liang
- College of Plant Protection, Yunnan Agricultural University, Kunming, Yunnan, 650201 China
| | - Lifang Li
- College of Plant Protection, Yunnan Agricultural University, Kunming, Yunnan, 650201 China
| | - Hang Zhao
- College of Plant Protection, Yunnan Agricultural University, Kunming, Yunnan, 650201 China
| | - Mingxian Lan
- College of Plant Protection, Yunnan Agricultural University, Kunming, Yunnan, 650201 China
| | - Yongyu Tang
- College of Plant Protection, Yunnan Agricultural University, Kunming, Yunnan, 650201 China
| | - Man Zhang
- College of Plant Protection, Yunnan Agricultural University, Kunming, Yunnan, 650201 China
| | - Deqiang Qin
- College of Plant Protection, Yunnan Agricultural University, Kunming, Yunnan, 650201 China
| | - Guoxing Wu
- College of Plant Protection, Yunnan Agricultural University, Kunming, Yunnan, 650201 China
| | - Xi Gao
- College of Plant Protection, Yunnan Agricultural University, Kunming, Yunnan, 650201 China
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13
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Yao Y, Li Y, Zhu X, Zhao C, Yang L, Huang X, Wang L. The emerging role of the piRNA/PIWI complex in respiratory tract diseases. Respir Res 2023; 24:76. [PMID: 36915129 PMCID: PMC10010017 DOI: 10.1186/s12931-023-02367-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Accepted: 02/14/2023] [Indexed: 03/16/2023] Open
Abstract
PIWI-interacting RNA (piRNA) is a class of recently discovered small non-coding RNA molecules with a length of 18-33 nt that interacts with the PIWI protein to form the piRNA/PIWI complex. The PIWI family is a subfamily of Argonaute (AGO) proteins that also contain the AGO family which bind to microRNA (miRNA). Recently studies indicate that piRNAs are not specific to in the mammalian germline, they are also expressed in a tissue-specific manner in a variety of human tissues and participated in various of diseases, such as cardiovascular, neurological, and urinary tract diseases, and are especially prevalent in malignant tumors in these systems. However, the functions and abnormal expression of piRNAs in respiratory tract diseases and their underlying mechanisms remain incompletely understood. In this review, we discuss current studies summarizing the biogenetic processes, functions, and emerging roles of piRNAs in respiratory tract diseases, providing a reference value for future piRNA research.
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Affiliation(s)
- Yizhu Yao
- Division of Pulmonary Medicine, The First Affiliated Hospital, Wenzhou Medical University, Wenzhou, 325000, Zhejiang, China
| | - Yaozhe Li
- Division of Pulmonary Medicine, The First Affiliated Hospital, Wenzhou Medical University, Wenzhou, 325000, Zhejiang, China
| | - Xiayan Zhu
- Division of Pulmonary Medicine, The First Affiliated Hospital, Wenzhou Medical University, Wenzhou, 325000, Zhejiang, China
| | - Chengguang Zhao
- Division of Pulmonary Medicine, The First Affiliated Hospital, Wenzhou Medical University, Wenzhou, 325000, Zhejiang, China.,School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou, 325035, Zhejiang, China
| | - Lehe Yang
- Division of Pulmonary Medicine, The First Affiliated Hospital, Wenzhou Medical University, Wenzhou, 325000, Zhejiang, China.
| | - Xiaoying Huang
- Division of Pulmonary Medicine, The First Affiliated Hospital, Wenzhou Medical University, Wenzhou, 325000, Zhejiang, China.
| | - Liangxing Wang
- Division of Pulmonary Medicine, The First Affiliated Hospital, Wenzhou Medical University, Wenzhou, 325000, Zhejiang, China.
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14
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Welsh SA, Gardini A. Genomic regulation of transcription and RNA processing by the multitasking Integrator complex. Nat Rev Mol Cell Biol 2023; 24:204-220. [PMID: 36180603 PMCID: PMC9974566 DOI: 10.1038/s41580-022-00534-2] [Citation(s) in RCA: 28] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/15/2022] [Indexed: 11/09/2022]
Abstract
In higher eukaryotes, fine-tuned activation of protein-coding genes and many non-coding RNAs pivots around the regulated activity of RNA polymerase II (Pol II). The Integrator complex is the only Pol II-associated large multiprotein complex that is metazoan specific, and has therefore been understudied for years. Integrator comprises at least 14 subunits, which are grouped into distinct functional modules. The phosphodiesterase activity of the core catalytic module is co-transcriptionally directed against several RNA species, including long non-coding RNAs (lncRNAs), U small nuclear RNAs (U snRNAs), PIWI-interacting RNAs (piRNAs), enhancer RNAs and nascent pre-mRNAs. Processing of non-coding RNAs by Integrator is essential for their biogenesis, and at protein-coding genes, Integrator is a key modulator of Pol II promoter-proximal pausing and transcript elongation. Recent studies have identified an Integrator-specific serine/threonine-protein phosphatase 2A (PP2A) module, which targets Pol II and other components of the basal transcription machinery. In this Review, we discuss how the activity of Integrator regulates transcription, RNA processing, chromatin landscape and DNA repair. We also discuss the diverse roles of Integrator in development and tumorigenesis.
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15
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Nguyen TTM, Munkhzul C, Kim J, Kyoung Y, Vianney M, Shin S, Ju S, Pham-Bui HA, Kim J, Kim JS, Lee M. In vivo profiling of the Zucchini proximal proteome in the Drosophila ovary. Development 2023; 150:286990. [PMID: 36762624 DOI: 10.1242/dev.201220] [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: 08/23/2022] [Accepted: 01/24/2023] [Indexed: 02/11/2023]
Abstract
PIWI-interacting RNAs (piRNAs) are small RNAs that play a conserved role in genome defense. The piRNA processing pathway is dependent on the sequestration of RNA precursors and protein factors in specific subcellular compartments. Therefore, a highly resolved spatial proteomics approach can help identify the local interactions and elucidate the unknown aspects of piRNA biogenesis. Herein, we performed TurboID proximity labeling to investigate the interactome of Zucchini (Zuc), a key factor of piRNA biogenesis in germline cells and somatic follicle cells of the Drosophila ovary. Quantitative mass spectrometry analysis of biotinylated proteins defined the Zuc-proximal proteome, including the well-known partners of Zuc. Many of these were enriched in the outer mitochondrial membrane (OMM), where Zuc was specifically localized. The proximal proteome of Zuc showed a distinct set of proteins compared with that of Tom20, a representative OMM protein, indicating that chaperone function-related and endomembrane system/vesicle transport proteins are previously unreported interacting partners of Zuc. The functional relevance of several candidates in piRNA biogenesis was validated by derepression of transposable elements after knockdown. Our results present potential Zuc-interacting proteins, suggesting unrecognized biological processes.
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Affiliation(s)
- Thi Thanh My Nguyen
- Soonchunhyang Institute of Medi-bio Science, Soonchunhyang University, Cheonan 31151, Korea
| | - Choijamts Munkhzul
- Soonchunhyang Institute of Medi-bio Science, Soonchunhyang University, Cheonan 31151, Korea
- Department of Integrated Biomedical Science, Soonchunhyang University, Cheonan 31151, Korea
| | - Jeesoo Kim
- Center for RNA Research, Institute for Basic Science, Seoul 08826, Korea
- School of Biological Sciences, Seoul National University, Seoul 08826, Korea
| | - Yeonju Kyoung
- Center for RNA Research, Institute for Basic Science, Seoul 08826, Korea
- School of Biological Sciences, Seoul National University, Seoul 08826, Korea
| | - Michele Vianney
- Soonchunhyang Institute of Medi-bio Science, Soonchunhyang University, Cheonan 31151, Korea
- Department of Integrated Biomedical Science, Soonchunhyang University, Cheonan 31151, Korea
| | - Sanghee Shin
- Center for RNA Research, Institute for Basic Science, Seoul 08826, Korea
- School of Biological Sciences, Seoul National University, Seoul 08826, Korea
| | - Seonmin Ju
- Center for RNA Research, Institute for Basic Science, Seoul 08826, Korea
- School of Biological Sciences, Seoul National University, Seoul 08826, Korea
| | - Hoang-Anh Pham-Bui
- Soonchunhyang Institute of Medi-bio Science, Soonchunhyang University, Cheonan 31151, Korea
- Department of Integrated Biomedical Science, Soonchunhyang University, Cheonan 31151, Korea
| | - Junhyung Kim
- Soonchunhyang Institute of Medi-bio Science, Soonchunhyang University, Cheonan 31151, Korea
- Department of Integrated Biomedical Science, Soonchunhyang University, Cheonan 31151, Korea
| | - Jong-Seo Kim
- Center for RNA Research, Institute for Basic Science, Seoul 08826, Korea
- School of Biological Sciences, Seoul National University, Seoul 08826, Korea
| | - Mihye Lee
- Soonchunhyang Institute of Medi-bio Science, Soonchunhyang University, Cheonan 31151, Korea
- Department of Integrated Biomedical Science, Soonchunhyang University, Cheonan 31151, Korea
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16
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Merkle JA. Dissection, Fixation, and Standard Staining of Adult Drosophila Ovaries. Methods Mol Biol 2023; 2626:49-68. [PMID: 36715899 DOI: 10.1007/978-1-0716-2970-3_3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Studies of the Drosophila ovary have provided significant insight into the molecular and cellular processes that control cell function, tissue organization, and animal development. To characterize mutants with defects in oogenesis or to observe the distribution of gene products involved in egg production, the ovaries must be carefully extracted and prepared for analysis. This chapter describes the manual dissection of ovaries from adult Drosophila females, followed by standard fixation and staining of the isolated tissue. Specifically, this chapter provides procedures for simple DNA and F-actin staining to assess cell and tissue morphology, as well as immunostaining to localize proteins of interest.
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Affiliation(s)
- Julie A Merkle
- Department of Biology, University of Evansville, Evansville, IN, USA.
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17
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Measuring Transposable Element Activity in Adult Drosophila Ovaries. Methods Mol Biol 2023; 2626:309-321. [PMID: 36715912 DOI: 10.1007/978-1-0716-2970-3_16] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Transposons are genetic elements that use various mechanisms of transposition to move around the genome, thus posing a risk to genomic integrity. Repression of transposable elements (TEs) involves the complex PIWI pathway and several proteins associated with heterochromatinization. All players of TE repression are indispensable for proper reproductive fitness, as loss-of-function mutations in these genes result primarily in sterility and impaired reproductive development. When investigating the function of novel genes with similar phenotypes, elevated transposon expression in reproductive tissues can be a marker for involvement in the aforementioned processes. Here, we present a protocol for investigating TE levels in adult Drosophila ovaries, from dissection to data analysis.
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18
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Wang X, Ramat A, Simonelig M, Liu MF. Emerging roles and functional mechanisms of PIWI-interacting RNAs. Nat Rev Mol Cell Biol 2023; 24:123-141. [PMID: 36104626 DOI: 10.1038/s41580-022-00528-0] [Citation(s) in RCA: 61] [Impact Index Per Article: 61.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/01/2022] [Indexed: 02/02/2023]
Abstract
PIWI-interacting RNAs (piRNAs) are a class of small non-coding RNAs that associate with proteins of the PIWI clade of the Argonaute family. First identified in animal germ line cells, piRNAs have essential roles in germ line development. The first function of PIWI-piRNA complexes to be described was the silencing of transposable elements, which is crucial for maintaining the integrity of the germ line genome. Later studies provided new insights into the functions of PIWI-piRNA complexes by demonstrating that they regulate protein-coding genes. Recent studies of piRNA biology, including in new model organisms such as golden hamsters, have deepened our understanding of both piRNA biogenesis and piRNA function. In this Review, we discuss the most recent advances in our understanding of piRNA biogenesis, the molecular mechanisms of piRNA function and the emerging roles of piRNAs in germ line development mainly in flies and mice, and in infertility, cancer and neurological diseases in humans.
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Affiliation(s)
- Xin Wang
- State Key Laboratory of Molecular Biology, Shanghai Key Laboratory of Molecular Andrology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China.,Key Laboratory of Systems Health Science of Zhejiang Province, School of Life Science, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou, China
| | - Anne Ramat
- Institute of Human Genetics, University of Montpellier, CNRS, Montpellier, France
| | - Martine Simonelig
- Institute of Human Genetics, University of Montpellier, CNRS, Montpellier, France.
| | - Mo-Fang Liu
- State Key Laboratory of Molecular Biology, Shanghai Key Laboratory of Molecular Andrology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China. .,Key Laboratory of Systems Health Science of Zhejiang Province, School of Life Science, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou, China. .,School of Life Science and Technology, Shanghai Tech University, Shanghai, China.
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19
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Miller DE, Dorador AP, Van Vaerenberghe K, Li A, Grantham EK, Cerbin S, Cummings C, Barragan M, Egidy RR, Scott AR, Hall KE, Perera A, Gilliland WD, Hawley RS, Blumenstiel JP. Off-target piRNA gene silencing in Drosophila melanogaster rescued by a transposable element insertion. PLoS Genet 2023; 19:e1010598. [PMID: 36809339 PMCID: PMC9983838 DOI: 10.1371/journal.pgen.1010598] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 03/03/2023] [Accepted: 01/04/2023] [Indexed: 02/23/2023] Open
Abstract
Transposable elements (TE) are selfish genetic elements that can cause harmful mutations. In Drosophila, it has been estimated that half of all spontaneous visible marker phenotypes are mutations caused by TE insertions. Several factors likely limit the accumulation of exponentially amplifying TEs within genomes. First, synergistic interactions between TEs that amplify their harm with increasing copy number are proposed to limit TE copy number. However, the nature of this synergy is poorly understood. Second, because of the harm posed by TEs, eukaryotes have evolved systems of small RNA-based genome defense to limit transposition. However, as in all immune systems, there is a cost of autoimmunity and small RNA-based systems that silence TEs can inadvertently silence genes flanking TE insertions. In a screen for essential meiotic genes in Drosophila melanogaster, a truncated Doc retrotransposon within a neighboring gene was found to trigger the germline silencing of ald, the Drosophila Mps1 homolog, a gene essential for proper chromosome segregation in meiosis. A subsequent screen for suppressors of this silencing identified a new insertion of a Hobo DNA transposon in the same neighboring gene. Here we describe how the original Doc insertion triggers flanking piRNA biogenesis and local gene silencing. We show that this local gene silencing occurs in cis and is dependent on deadlock, a component of the Rhino-Deadlock-Cutoff (RDC) complex, to trigger dual-strand piRNA biogenesis at TE insertions. We further show how the additional Hobo insertion leads to de-silencing by reducing flanking piRNA biogenesis triggered by the original Doc insertion. These results support a model of TE-mediated gene silencing by piRNA biogenesis in cis that depends on local determinants of transcription. This may explain complex patterns of off-target gene silencing triggered by TEs within populations and in the laboratory. It also provides a mechanism of sign epistasis among TE insertions, illuminates the complex nature of their interactions and supports a model in which off-target gene silencing shapes the evolution of the RDC complex.
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Affiliation(s)
- Danny E. Miller
- Stowers Institute for Medical Research, Kansas City, Missouri, United States of America
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, Kansas, United States of America
- Division of Genetic Medicine, Department of Pediatrics, University of Washington and Seattle Children’s Hospital, Seattle, Washington, United States of America
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, Washington, United States of America
| | - Ana P. Dorador
- Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, Kansas, United States of America
| | - Kelley Van Vaerenberghe
- Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, Kansas, United States of America
- Division of Biological Sciences, University of Montana, Missoula, Montana, United States of America
| | - Angela Li
- Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, Kansas, United States of America
| | - Emily K. Grantham
- Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, Kansas, United States of America
| | - Stefan Cerbin
- Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, Kansas, United States of America
| | - Celeste Cummings
- Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, Kansas, United States of America
| | - Marilyn Barragan
- Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, Kansas, United States of America
| | - Rhonda R. Egidy
- Stowers Institute for Medical Research, Kansas City, Missouri, United States of America
| | - Allison R. Scott
- Stowers Institute for Medical Research, Kansas City, Missouri, United States of America
| | - Kate E. Hall
- Stowers Institute for Medical Research, Kansas City, Missouri, United States of America
| | - Anoja Perera
- Stowers Institute for Medical Research, Kansas City, Missouri, United States of America
| | - William D. Gilliland
- Department of Biological Sciences, DePaul University, Chicago, Illinois, United States of America
| | - R. Scott Hawley
- Stowers Institute for Medical Research, Kansas City, Missouri, United States of America
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, Kansas, United States of America
| | - Justin P. Blumenstiel
- Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, Kansas, United States of America
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20
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Liu Z, Zhang S, Zhu Y, Jing T, Su H, Hu J, Jiang X, Yang Y. Reproduction Evaluation and Transcription Analysis of Aphis gossypii under Various Photoperiods. INSECTS 2022; 13:1105. [PMID: 36555015 PMCID: PMC9787806 DOI: 10.3390/insects13121105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Revised: 11/26/2022] [Accepted: 11/27/2022] [Indexed: 06/17/2023]
Abstract
Aphis gossypii Glover (Hemiptera, Aphidoidae) is a polyphagous pest, whose complex phenotypic form, combined with its high fecundity and short reproductive cycle, has caused serious economic losses to agriculture worldwide. Photoperiod plays an important role in the reproduction of aphids. However, the molecular mechanisms underlying its response to seasonal photoperiodic changes are not known. In this study, the effects of different photoperiod treatments (8 L:16 D, 10 L:14 D, 12 L:12 D and 14 L:10 D) on A. gossypii reproduction in the first, third, and fifth generations at low temperatures were investigated. Then, transcriptome sequencing analysis was performed after the fifth generation of A. gossypii, exposed to different photoperiods (8 L:16 D and 12 L:12 D), using high-throughput sequencing technology. The results showed that (I) the effect of photoperiod on aphids was gradually evident with increasing exposure generations. In general, daylight extension help the A. gossypii to reproduce with the optimum photoperiod of L:D 12:12. (II) The transcriptome analysis results showed that 170 differentially expressed genes (DEGs) (123 downregulated and 47 upregulated genes) were identified between aphids under 8 h daylight and 12 h daylight. (III) Gene Ontology (GO) enrichment analysis showed that the DEGs involved in "proteolysis", "metabolic process", "peptidase activity" and "structural molecule activity" were significantly enriched; Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis showed that there were more DEGs in "Longevity regulating pathway-multiple species", "Lysosome", "Endocytosis", "Spliceosome" and "Protein processing in endoplasmic reticulum". (IV) Ten related genes were chosen for validation of statistical analysis based on RNA-Seq by the reverse transcription quantitative (RT-qPCR). The comparison was consistent with the expression pattern and supported the accuracy and reliability of RNA-Seq. In summary, the genes involved in these pathways play an important role in the reproduction of A. gossypii under photoperiodical changes. These will contribute to the sustainable management of cotton aphids through the disruption of their reproduction by the method of RNA interference in the future.
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21
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Palozzi JM, Jeedigunta SP, Minenkova AV, Monteiro VL, Thompson ZS, Lieber T, Hurd TR. Mitochondrial DNA quality control in the female germline requires a unique programmed mitophagy. Cell Metab 2022; 34:1809-1823.e6. [PMID: 36323236 DOI: 10.1016/j.cmet.2022.10.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Revised: 08/22/2022] [Accepted: 10/06/2022] [Indexed: 11/07/2022]
Abstract
Mitochondria have their own DNA (mtDNA), which is susceptible to the accumulation of disease-causing mutations. To prevent deleterious mutations from being inherited, the female germline has evolved a conserved quality control mechanism that remains poorly understood. Here, through a large-scale screen, we uncover a unique programmed germline mitophagy (PGM) that is essential for mtDNA quality control. We find that PGM is developmentally triggered as germ cells enter meiosis by inhibition of the target of rapamycin complex 1 (TORC1). We identify a role for the RNA-binding protein Ataxin-2 (Atx2) in coordinating the timing of PGM with meiosis. We show that PGM requires the mitophagy receptor BNIP3, mitochondrial fission and translation factors, and members of the Atg1 complex, but not the mitophagy factors PINK1 and Parkin. Additionally, we report several factors that are critical for germline mtDNA quality control and show that pharmacological manipulation of one of these factors promotes mtDNA quality control.
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Affiliation(s)
- Jonathan M Palozzi
- Department of Molecular Genetics, University of Toronto, 661 University Avenue, Toronto, ON M5G 1M1, Canada
| | - Swathi P Jeedigunta
- Department of Molecular Genetics, University of Toronto, 661 University Avenue, Toronto, ON M5G 1M1, Canada
| | - Anastasia V Minenkova
- Department of Molecular Genetics, University of Toronto, 661 University Avenue, Toronto, ON M5G 1M1, Canada
| | - Vernon L Monteiro
- Department of Molecular Genetics, University of Toronto, 661 University Avenue, Toronto, ON M5G 1M1, Canada
| | - Zoe S Thompson
- Department of Molecular Genetics, University of Toronto, 661 University Avenue, Toronto, ON M5G 1M1, Canada
| | - Toby Lieber
- HHMI and Kimmel Center for Biology and Medicine of the Skirball Institute, Department of Cell Biology, New York University School of Medicine, New York, NY, USA
| | - Thomas R Hurd
- Department of Molecular Genetics, University of Toronto, 661 University Avenue, Toronto, ON M5G 1M1, Canada.
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22
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Ipsaro JJ, Joshua‐Tor L. Developmental roles and molecular mechanisms of Asterix/GTSF1. WIRES RNA 2022; 13:e1716. [PMID: 35108755 PMCID: PMC9539491 DOI: 10.1002/wrna.1716] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 11/29/2021] [Accepted: 11/30/2021] [Indexed: 01/07/2023]
Abstract
Maintenance of germline genomic integrity is critical for the survival of animal species. Consequently, many cellular and molecular processes have evolved to ensure genetic stability during the production of gametes. Here, we describe the discovery, characterization, and emerging molecular mechanisms of the protein Asterix/Gametocyte‐specific factor 1 (GTSF1), an essential gametogenesis factor that is conserved from insects to humans. Beyond its broad importance for healthy germline development, Asterix/GTSF1 has more specific functions in the Piwi‐interacting RNA (piRNA)–RNA interference pathway. There, it contributes to the repression of otherwise deleterious transposons, helping to ensure faithful transmission of genetic information to the next generation. This article is categorized under:Regulatory RNAs/RNAi/Riboswitches > RNAi: Mechanisms of Action Regulatory RNAs/RNAi/Riboswitches > Regulatory RNAs RNA Interactions with Proteins and Other Molecules > RNA‐Protein Complexes RNA Interactions with Proteins and Other Molecules > Protein‐RNA Interactions: Functional Implications
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Affiliation(s)
- Jonathan J. Ipsaro
- Howard Hughes Medical Institute W.M. Keck Structural Biology Laboratory, Cold Spring Harbor Laboratory Cold Spring Harbor New York USA
| | - Leemor Joshua‐Tor
- Howard Hughes Medical Institute W.M. Keck Structural Biology Laboratory, Cold Spring Harbor Laboratory Cold Spring Harbor New York USA
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23
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Zinshteyn D, Barbash DA. Stonewall prevents expression of ectopic genes in the ovary and accumulates at insulator elements in D. melanogaster. PLoS Genet 2022; 18:e1010110. [PMID: 35324887 PMCID: PMC8982855 DOI: 10.1371/journal.pgen.1010110] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 04/05/2022] [Accepted: 02/18/2022] [Indexed: 11/29/2022] Open
Abstract
Germline stem cells (GSCs) are the progenitor cells of the germline for the lifetime of an animal. In Drosophila, these cells reside in a cellular niche that is required for both their maintenance (self-renewal) and differentiation (asymmetric division resulting in a daughter cell that differs from the GSC). The stem cell—daughter cell transition is tightly regulated by a number of processes, including an array of proteins required for genome stability. The germline stem-cell maintenance factor Stonewall (Stwl) associates with heterochromatin, but its molecular function is poorly understood. We performed RNA-Seq on stwl mutant ovaries and found significant derepression of many transposon families but not heterochromatic genes. We also discovered inappropriate expression of multiple classes of genes. Most prominent are testis-enriched genes, including the male germline sex-determination switch Phf7, the differentiation factor bgcn, and a large testis-specific gene cluster on chromosome 2, all of which are upregulated or ectopically expressed in stwl mutant ovaries. Surprisingly, we also found that RNAi knockdown of stwl in somatic S2 cells results in ectopic expression of these testis genes. Using parallel ChIP-Seq and RNA-Seq experiments in S2 cells, we discovered that Stwl localizes upstream of transcription start sites and at heterochromatic sequences including repetitive sequences associated with telomeres. Stwl is also enriched at bgcn, suggesting that it directly regulates this essential differentiation factor. Finally, we identify Stwl binding motifs that are shared with known insulator binding proteins. We propose that Stwl affects gene regulation, including repression of male transcripts in the female germline, by binding insulators and establishing chromatin boundaries. Stem cells are defined by their ability to divide asymmetrically, resulting in a differentiated cell and a stem cell daughter. In fruit flies, sperm and egg production begins with germline stem cells (GSCs). The ability of a GSC to differentiate or self-renew is tightly regulated by a myriad of factors. Some of these are transcription factors, which are responsible for activating or suppressing other genes to promote one state in favor of another. Stonewall is an ovarian nuclear protein required for GSC self-renewal, whose molecular function is poorly understood. Here we show that Stonewall is responsible for preventing the activation of “male” molecular programming in the fruit fly ovary. When Stonewall is absent from the ovary, egg production is terminated and testis-specific genes become highly expressed, including the male transcript of Phf7, which induces male sexual identity in female germ cells. We also show that Stonewall is likely localizing to genomic insulators, which are regions of the genome that shield genes from nearby regulators. Our findings suggest that Stonewall helps to organize the genome in ovarian germ cells and prevent expression of male genes.
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Affiliation(s)
- Daniel Zinshteyn
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York, United States of America
| | - Daniel A. Barbash
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York, United States of America
- * E-mail:
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24
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La Rocca G, Cavalieri V. Roles of the Core Components of the Mammalian miRISC in Chromatin Biology. Genes (Basel) 2022; 13:414. [PMID: 35327968 PMCID: PMC8954937 DOI: 10.3390/genes13030414] [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: 12/21/2021] [Revised: 02/20/2022] [Accepted: 02/23/2022] [Indexed: 12/16/2022] Open
Abstract
The Argonaute (AGO) and the Trinucleotide Repeat Containing 6 (TNRC6) family proteins are the core components of the mammalian microRNA-induced silencing complex (miRISC), the machinery that mediates microRNA function in the cytoplasm. The cytoplasmic miRISC-mediated post-transcriptional gene repression has been established as the canonical mechanism through which AGO and TNRC6 proteins operate. However, growing evidence points towards an additional mechanism through which AGO and TNRC6 regulate gene expression in the nucleus. While several mechanisms through which miRISC components function in the nucleus have been described, in this review we aim to summarize the major findings that have shed light on the role of AGO and TNRC6 in mammalian chromatin biology and on the implications these novel mechanisms may have in our understanding of regulating gene expression.
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Affiliation(s)
- Gaspare La Rocca
- Cancer Biology and Genetics Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Vincenzo Cavalieri
- Department of Biological, Chemical and Pharmaceutical Sciences and Technologies, University of Palermo, 90128 Palermo, Italy
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25
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Andreev VI, Yu C, Wang J, Schnabl J, Tirian L, Gehre M, Handler D, Duchek P, Novatchkova M, Baumgartner L, Meixner K, Sienski G, Patel DJ, Brennecke J. Panoramix SUMOylation on chromatin connects the piRNA pathway to the cellular heterochromatin machinery. Nat Struct Mol Biol 2022; 29:130-142. [PMID: 35173350 DOI: 10.1038/s41594-022-00721-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Accepted: 12/30/2021] [Indexed: 11/09/2022]
Abstract
Nuclear Argonaute proteins, guided by small RNAs, mediate sequence-specific heterochromatin formation. The molecular principles that link Argonaute-small RNA complexes to cellular heterochromatin effectors on binding to nascent target RNAs are poorly understood. Here, we explain the mechanism by which the PIWI-interacting RNA (piRNA) pathway connects to the heterochromatin machinery in Drosophila. We find that Panoramix, a corepressor required for piRNA-guided heterochromatin formation, is SUMOylated on chromatin in a Piwi-dependent manner. SUMOylation, together with an amphipathic LxxLL motif in Panoramix's intrinsically disordered repressor domain, are necessary and sufficient to recruit Small ovary (Sov), a multi-zinc-finger protein essential for general heterochromatin formation and viability. Structure-guided mutations that eliminate the Panoramix-Sov interaction or that prevent SUMOylation of Panoramix uncouple Sov from the piRNA pathway, resulting in viable but sterile flies in which Piwi-targeted transposons are derepressed. Thus, Piwi engages the heterochromatin machinery specifically at transposon loci by coupling recruitment of a corepressor to nascent transcripts with its SUMOylation.
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Affiliation(s)
- Veselin I Andreev
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna BioCenter (VBC), Vienna, Austria.,Vienna BioCenter PhD Program, Doctoral School of the University of Vienna and Medical University of Vienna, Vienna, Austria
| | - Changwei Yu
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna BioCenter (VBC), Vienna, Austria
| | - Juncheng Wang
- Structural Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Jakob Schnabl
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna BioCenter (VBC), Vienna, Austria.,Vienna BioCenter PhD Program, Doctoral School of the University of Vienna and Medical University of Vienna, Vienna, Austria
| | - Laszlo Tirian
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna BioCenter (VBC), Vienna, Austria
| | - Maja Gehre
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna BioCenter (VBC), Vienna, Austria
| | - Dominik Handler
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna BioCenter (VBC), Vienna, Austria
| | - Peter Duchek
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna BioCenter (VBC), Vienna, Austria
| | - Maria Novatchkova
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna BioCenter (VBC), Vienna, Austria
| | - Lisa Baumgartner
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna BioCenter (VBC), Vienna, Austria.,Vienna BioCenter PhD Program, Doctoral School of the University of Vienna and Medical University of Vienna, Vienna, Austria
| | - Katharina Meixner
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna BioCenter (VBC), Vienna, Austria
| | - Grzegorz Sienski
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna BioCenter (VBC), Vienna, Austria.,Vienna BioCenter PhD Program, Doctoral School of the University of Vienna and Medical University of Vienna, Vienna, Austria
| | - Dinshaw J Patel
- Structural Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Julius Brennecke
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna BioCenter (VBC), Vienna, Austria.
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26
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ElMaghraby MF, Tirian L, Senti KA, Meixner K, Brennecke J. A genetic toolkit for studying transposon control in the Drosophila melanogaster ovary. Genetics 2022; 220:iyab179. [PMID: 34718559 PMCID: PMC8733420 DOI: 10.1093/genetics/iyab179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Accepted: 09/19/2021] [Indexed: 11/12/2022] Open
Abstract
Argonaute proteins of the PIWI clade complexed with PIWI-interacting RNAs (piRNAs) protect the animal germline genome by silencing transposable elements. One of the leading experimental systems for studying piRNA biology is the Drosophila melanogaster ovary. In addition to classical mutagenesis, transgenic RNA interference (RNAi), which enables tissue-specific silencing of gene expression, plays a central role in piRNA research. Here, we establish a versatile toolkit focused on piRNA biology that combines germline transgenic RNAi, GFP marker lines for key proteins of the piRNA pathway, and reporter transgenes to establish genetic hierarchies. We compare constitutive, pan-germline RNAi with an equally potent transgenic RNAi system that is activated only after germ cell cyst formation. Stage-specific RNAi allows us to investigate the role of genes essential for germline cell survival, for example, nuclear RNA export or the SUMOylation pathway, in piRNA-dependent and independent transposon silencing. Our work forms the basis for an expandable genetic toolkit provided by the Vienna Drosophila Resource Center.
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Affiliation(s)
- Mostafa F ElMaghraby
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna BioCenter (VBC), Vienna 1030, Austria
- Vienna BioCenter PhD Program, Doctoral School at the University of Vienna and Medical University of Vienna, Vienna 1030, Austria
| | - Laszlo Tirian
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna BioCenter (VBC), Vienna 1030, Austria
| | - Kirsten-André Senti
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna BioCenter (VBC), Vienna 1030, Austria
| | - Katharina Meixner
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna BioCenter (VBC), Vienna 1030, Austria
| | - Julius Brennecke
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna BioCenter (VBC), Vienna 1030, Austria
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27
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Saito K. Drosophila Genetic Resources for Elucidating piRNA Pathway. Methods Mol Biol 2022; 2509:135-141. [PMID: 35796961 DOI: 10.1007/978-1-0716-2380-0_8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Emerging evidence indicates that PIWI proteins, in collaboration with PIWI-interacting RNAs (piRNAs), play a critical role in gonadal development and retrotransposon silencing in metazoans. Numerous studies have characterized the mechanism of retrotransposon silencing and identified dozens of factors involved in the piRNA pathways. Drosophila is an attractive model organism for piRNA studies due to its great availability of genetic tools and the low cost of maintenance. Here, I introduce Drosophila genetic resources and techniques valuable for studying piRNA pathway genes via their impact on retrotransposon silencing.
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Affiliation(s)
- Kuniaki Saito
- Invertebrate Genetics Laboratory, Department of Chromosome Science, National Institute of Genetics, Research Organization of Information and Systems (ROIS), Mishima, Shizuoka, Japan.
- Division of Invertebrate Genetics, Department of Genetics, The Graduate University for Advanced Studies (SOKENDAI), Mishima, Shizuoka, Japan.
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28
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Complex Genetic Interactions between Piwi and HP1a in the Repression of Transposable Elements and Tissue-Specific Genes in the Ovarian Germline. Int J Mol Sci 2021; 22:ijms222413430. [PMID: 34948223 PMCID: PMC8707237 DOI: 10.3390/ijms222413430] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 12/03/2021] [Accepted: 12/10/2021] [Indexed: 11/16/2022] Open
Abstract
Insertions of transposable elements (TEs) in eukaryotic genomes are usually associated with repressive chromatin, which spreads to neighbouring genomic sequences. In ovaries of Drosophila melanogaster, the Piwi-piRNA pathway plays a key role in the transcriptional silencing of TEs considered to be exerted mostly through the establishment of H3K9me3 histone marks recruiting Heterochromatin Protein 1a (HP1a). Here, using RNA-seq, we investigated the expression of TEs and the adjacent genomic regions upon Piwi and HP1a germline knockdowns sharing a similar genetic background. We found that the depletion of Piwi and HP1a led to the derepression of only partially overlapping TE sets. Several TEs were silenced predominantly by HP1a, whereas the upregulation of some other TEs was more pronounced upon Piwi knockdown and, surprisingly, was diminished upon a Piwi/HP1a double-knockdown. We revealed that HP1a loss influenced the expression of thousands of protein-coding genes mostly not adjacent to TE insertions and, in particular, downregulated a putative transcriptional factor required for TE activation. Nevertheless, our results indicate that Piwi and HP1a cooperatively exert repressive effects on the transcription of euchromatic loci flanking the insertions of some Piwi-regulated TEs. We suggest that this mechanism controls the silencing of a small set of TE-adjacent tissue-specific genes, preventing their inappropriate expression in ovaries.
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29
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The birth of piRNAs: how mammalian piRNAs are produced, originated, and evolved. Mamm Genome 2021; 33:293-311. [PMID: 34724117 PMCID: PMC9114089 DOI: 10.1007/s00335-021-09927-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Accepted: 10/15/2021] [Indexed: 11/24/2022]
Abstract
PIWI-interacting RNAs (piRNAs), small noncoding RNAs 24–35 nucleotides long, are essential for animal fertility. They play critical roles in a range of functions, including transposable element suppression, gene expression regulation, imprinting, and viral defense. In mammals, piRNAs are the most abundant small RNAs in adult testes and the only small RNAs that direct epigenetic modification of chromatin in the nucleus. The production of piRNAs is a complex process from transcription to post-transcription, requiring unique machinery often distinct from the biogenesis of other RNAs. In mice, piRNA biogenesis occurs in specialized subcellular locations, involves dynamic developmental regulation, and displays sexual dimorphism. Furthermore, the genomic loci and sequences of piRNAs evolve much more rapidly than most of the genomic regions. Understanding piRNA biogenesis should reveal novel RNA regulations recognizing and processing piRNA precursors and the forces driving the gain and loss of piRNAs during animal evolution. Such findings may provide the basis for the development of engineered piRNAs capable of modulating epigenetic regulation, thereby offering possible single-dose RNA therapy without changing the genomic DNA. In this review, we focus on the biogenesis of piRNAs in mammalian adult testes that are derived from long non-coding RNAs. Although piRNA biogenesis is believed to be evolutionarily conserved from fruit flies to humans, recent studies argue for the existence of diverse, mammalian-specific RNA-processing pathways that convert precursor RNAs into piRNAs, perhaps associated with the unique features of mammalian piRNAs or germ cell development. We end with the discussion of major questions in the field, including substrate recognition and the birth of new piRNAs.
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30
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Nallasivan MP, Haussmann IU, Civetta A, Soller M. Channel nuclear pore protein 54 directs sexual differentiation and neuronal wiring of female reproductive behaviors in Drosophila. BMC Biol 2021; 19:226. [PMID: 34666772 PMCID: PMC8527774 DOI: 10.1186/s12915-021-01154-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Accepted: 09/15/2021] [Indexed: 11/23/2022] Open
Abstract
Background Female reproductive behaviors and physiology change profoundly after mating. The control of pregnancy-associated changes in physiology and behaviors are largely hard-wired into the brain to guarantee reproductive success, yet the gene expression programs that direct neuronal differentiation and circuit wiring at the end of the sex determination pathway in response to mating are largely unknown. In Drosophila, the post-mating response induced by male-derived sex-peptide in females is a well-established model to elucidate how complex innate behaviors are hard-wired into the brain. Here, we use a genetic approach to further characterize the molecular and cellular architecture of the sex-peptide response in Drosophila females. Results Screening for mutations that affect the sensitivity to sex-peptide, we identified the channel nuclear pore protein Nup54 gene as an essential component for mediating the sex-peptide response, with viable mutant alleles leading to the inability of laying eggs and reducing receptivity upon sex-peptide exposure. Nup54 directs correct wiring of eight adult brain neurons that express pickpocket and are required for egg-laying, while additional channel Nups also mediate sexual differentiation. Consistent with links of Nups to speciation, the Nup54 promoter is a hot spot for rapid evolution and promoter variants alter nucleo-cytoplasmic shuttling. Conclusions These results implicate nuclear pore functionality to neuronal wiring underlying the sex-peptide response and sexual differentiation as a response to sexual conflict arising from male-derived sex-peptide to direct the female post-mating response. Supplementary Information The online version contains supplementary material available at 10.1186/s12915-021-01154-6.
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Affiliation(s)
- Mohanakarthik P Nallasivan
- School of Biosciences, College of Life and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Irmgard U Haussmann
- School of Biosciences, College of Life and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.,Department of Life Science, School of Health Sciences, Birmingham City University, Birmingham, B15 3TN, UK
| | - Alberto Civetta
- Department of Biology, University of Winnipeg, Winnipeg, MB, R3B 2E9, Canada
| | - Matthias Soller
- School of Biosciences, College of Life and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK. .,Birmingham Centre for Genome Biology, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.
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31
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Loss of telomere silencing is accompanied by dysfunction of Polo kinase and centrosomes during Drosophila oogenesis and early development. PLoS One 2021; 16:e0258156. [PMID: 34624021 PMCID: PMC8500440 DOI: 10.1371/journal.pone.0258156] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Accepted: 09/18/2021] [Indexed: 12/03/2022] Open
Abstract
Telomeres are nucleoprotein complexes that protect the ends of eukaryotic linear chromosomes from degradation and fusions. Telomere dysfunction leads to cell growth arrest, oncogenesis, and premature aging. Telomeric RNAs have been found in all studied species; however, their functions and biogenesis are not clearly understood. We studied the mechanisms of development disorders observed upon overexpression of telomeric repeats in Drosophila. In somatic cells, overexpression of telomeric retrotransposon HeT-A is cytotoxic and leads to the accumulation of HeT-A Gag near centrosomes. We found that RNA and RNA-binding protein Gag encoded by the telomeric retrotransposon HeT-A interact with Polo and Cdk1 mitotic kinases, which are conserved regulators of centrosome biogenesis and cell cycle. The depletion of proteins Spindle E, Ccr4 or Ars2 resulting in HeT-A overexpression in the germline was accompanied by mislocalization of Polo as well as its abnormal stabilization during oogenesis and severe deregulation of centrosome biogenesis leading to maternal-effect embryonic lethality. These data suggest a mechanistic link between telomeric HeT-A ribonucleoproteins and cell cycle regulators that ensures the cell response to telomere dysfunction.
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32
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Zhang G, Yu T, Parhad SS, Ho S, Weng Z, Theurkauf WE. piRNA-independent transposon silencing by the Drosophila THO complex. Dev Cell 2021; 56:2623-2635.e5. [PMID: 34547226 DOI: 10.1016/j.devcel.2021.08.021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Revised: 06/18/2021] [Accepted: 08/27/2021] [Indexed: 12/19/2022]
Abstract
piRNAs guide Piwi/Panoramix-dependent H3K9me3 chromatin modification and transposon silencing during Drosophila germline development. The THO RNA export complex is composed of Hpr1, Tho2, and Thoc5-7. Null thoc7 mutations, which displace Thoc5 and Thoc6 from a Tho2-Hpr1 subcomplex, reduce expression of a subset of germline piRNAs and increase transposon expression, suggesting that THO silences transposons by promoting piRNA biogenesis. Here, we show that the thoc7-null mutant combination increases transposon transcription but does not reduce anti-sense piRNAs targeting half of the transcriptionally activated transposon families. These mutations also fail to reduce piRNA-guided H3K9me3 chromatin modification or block Panoramix-dependent silencing of a reporter transgene, and unspliced transposon transcripts co-precipitate with THO through a Piwi- and Panoramix-independent mechanism. Mutations in piwi also dominantly enhance germline defects associated with thoc7-null alleles. THO thus functions in a piRNA-independent transposon-silencing pathway, which acts cooperatively with Piwi to support germline development.
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Affiliation(s)
- Gen Zhang
- Program in Molecular Medicine, University of Massachusetts Medical School, 373 Plantation Street, Worcester, MA 01605, USA
| | - Tianxiong Yu
- Program in Bioinformatics and Integrative Biology, University of Massachusetts Medical School, 373 Plantation Street, Worcester, MA 01605, USA; Department of Bioinformatics, School of Life Sciences and Technology, Tongji University, Shanghai, People's Republic of China
| | - Swapnil S Parhad
- Program in Molecular Medicine, University of Massachusetts Medical School, 373 Plantation Street, Worcester, MA 01605, USA
| | - Samantha Ho
- Program in Molecular Medicine, University of Massachusetts Medical School, 373 Plantation Street, Worcester, MA 01605, USA
| | - Zhiping Weng
- Program in Bioinformatics and Integrative Biology, University of Massachusetts Medical School, 373 Plantation Street, Worcester, MA 01605, USA.
| | - William E Theurkauf
- Program in Molecular Medicine, University of Massachusetts Medical School, 373 Plantation Street, Worcester, MA 01605, USA.
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33
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Makeyeva YV, Shirayama M, Mello CC. Cues from mRNA splicing prevent default Argonaute silencing in C. elegans. Dev Cell 2021; 56:2636-2648.e4. [PMID: 34547227 DOI: 10.1016/j.devcel.2021.08.022] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Revised: 06/28/2021] [Accepted: 08/27/2021] [Indexed: 12/12/2022]
Abstract
In animals, Argonaute small-RNA pathways scan germline transcripts to silence self-replicating genetic elements. However, little is known about how endogenous gene expression is recognized and licensed. Here, we show that the presence of introns and, by inference, the process of mRNA splicing prevents default Argonaute-mediated silencing in the C. elegans germline. The silencing of intronless genes is initiated independently of the piRNA pathway but nevertheless engages multiple components of the downstream amplification and maintenance mechanisms that mediate transgenerational silencing, including both nuclear and cytoplasmic members of the worm-specific Argonaute gene family (WAGOs). Small RNAs amplified from intronless mRNAs can trans-silence cognate intron-containing genes. Interestingly, a second, small RNA-independent cis-acting mode of silencing also acts on intronless mRNAs. Our findings suggest that cues put in place during mRNA splicing license germline gene expression and provide evidence for a splicing-dependent and dsRNA- and piRNA-independent mechanism that can program Argonaute silencing.
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Affiliation(s)
- Yekaterina V Makeyeva
- RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Masaki Shirayama
- RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, MA 01605, USA; Howard Hughes Medical Institute, Worcester, MA 01605, USA
| | - Craig C Mello
- RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, MA 01605, USA; Howard Hughes Medical Institute, Worcester, MA 01605, USA.
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34
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Chen P, Luo Y, Aravin AA. RDC complex executes a dynamic piRNA program during Drosophila spermatogenesis to safeguard male fertility. PLoS Genet 2021; 17:e1009591. [PMID: 34473737 PMCID: PMC8412364 DOI: 10.1371/journal.pgen.1009591] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2020] [Accepted: 05/10/2021] [Indexed: 11/19/2022] Open
Abstract
piRNAs are small non-coding RNAs that guide the silencing of transposons and other targets in animal gonads. In Drosophila female germline, many piRNA source loci dubbed “piRNA clusters” lack hallmarks of active genes and exploit an alternative path for transcription, which relies on the Rhino-Deadlock-Cutoff (RDC) complex. RDC was thought to be absent in testis, so it remains to date unknown how piRNA cluster transcription is regulated in the male germline. We found that components of RDC complex are expressed in male germ cells during early spermatogenesis, from germline stem cells (GSCs) to early spermatocytes. RDC is essential for expression of dual-strand piRNA clusters and transposon silencing in testis; however, it is dispensable for expression of Y-linked Suppressor of Stellate piRNAs and therefore Stellate silencing. Despite intact Stellate repression, males lacking RDC exhibited compromised fertility accompanied by germline DNA damage and GSC loss. Thus, piRNA-guided repression is essential for normal spermatogenesis beyond Stellate silencing. While RDC associates with multiple piRNA clusters in GSCs and early spermatogonia, its localization changes in later stages as RDC concentrates on a single X-linked locus, AT-chX. Dynamic RDC localization is paralleled by changes in piRNA cluster expression, indicating that RDC executes a fluid piRNA program during different stages of spermatogenesis. These results disprove the common belief that RDC is dispensable for piRNA biogenesis in testis and uncover the unexpected, sexually dimorphic and dynamic behavior of a core piRNA pathway machinery. Large fractions of eukaryotic genomes are occupied by mobile genetic elements called transposons. Active transposons can move in the genome causing DNA damage and mutations, while inactive copies can contribute to chromosome organization and regulation of gene expression. Host cells employ several mechanisms to discriminate transposons from other genes and repress transposon activities. In germ cells, a conserved class of short RNAs called Piwi-interacting (pi)RNAs recognize target RNAs in both the nucleus and cytoplasm and then guide transposon repression by preventing their transcription and destroying their RNAs. piRNAs are encoded in extended genomic regions dubbed piRNA clusters. Previously, composition and regulation of piRNA clusters were studied in the female germline of fruit flies, where a nuclear protein complex, the RDC complex, was shown to promote non-canonical transcription of these regions. However, RDC was believed to be dispensable in males. Here, we showed that RDC is essential for transposon repression in males, and males lacking RDC exhibit compromised fertility and loss of germ cells. We found that RDC binds multiple piRNA clusters in early germ cells but concentrates on a single locus at later stages. Our results indicate dynamic regulation of loci that produce piRNAs and, therefore, piRNA targets throughout spermatogenesis.
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Affiliation(s)
- Peiwei Chen
- California Institute of Technology, Division of Biology and Biological Engineering, Pasadena, California, United States of America
- * E-mail: (PC); (AAA)
| | - Yicheng Luo
- California Institute of Technology, Division of Biology and Biological Engineering, Pasadena, California, United States of America
| | - Alexei A. Aravin
- California Institute of Technology, Division of Biology and Biological Engineering, Pasadena, California, United States of America
- * E-mail: (PC); (AAA)
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35
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Onishi R, Yamanaka S, Siomi MC. piRNA- and siRNA-mediated transcriptional repression in Drosophila, mice, and yeast: new insights and biodiversity. EMBO Rep 2021; 22:e53062. [PMID: 34347367 PMCID: PMC8490990 DOI: 10.15252/embr.202153062] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 06/10/2021] [Accepted: 07/19/2021] [Indexed: 12/26/2022] Open
Abstract
The PIWI‐interacting RNA (piRNA) pathway acts as a self‐defense mechanism against transposons to maintain germline genome integrity. Failures in the piRNA pathway cause DNA damage in the germline genome, disturbing inheritance of “correct” genetic information by the next generations and leading to infertility. piRNAs execute transposon repression in two ways: degrading their RNA transcripts and compacting the genomic loci via heterochromatinization. The former event is mechanistically similar to siRNA‐mediated RNA cleavage that occurs in the cytoplasm and has been investigated in many species including nematodes, fruit flies, and mammals. The latter event seems to be mechanistically parallel to siRNA‐centered kinetochore assembly and subsequent chromosome segregation, which has so far been studied particularly in fission yeast. Despite the interspecies conservations, the overall schemes of the nuclear events show clear biodiversity across species. In this review, we summarize the recent progress regarding piRNA‐mediated transcriptional silencing in Drosophila and discuss the biodiversity by comparing it with the equivalent piRNA‐mediated system in mice and the siRNA‐mediated system in fission yeast.
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Affiliation(s)
- Ryo Onishi
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Soichiro Yamanaka
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Mikiko C Siomi
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
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36
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Wei X, Eickbush DG, Speece I, Larracuente AM. Heterochromatin-dependent transcription of satellite DNAs in the Drosophila melanogaster female germline. eLife 2021; 10:e62375. [PMID: 34259629 PMCID: PMC8321551 DOI: 10.7554/elife.62375] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2020] [Accepted: 07/08/2021] [Indexed: 12/15/2022] Open
Abstract
Large blocks of tandemly repeated DNAs-satellite DNAs (satDNAs)-play important roles in heterochromatin formation and chromosome segregation. We know little about how satDNAs are regulated; however, their misregulation is associated with genomic instability and human diseases. We use the Drosophila melanogaster germline as a model to study the regulation of satDNA transcription and chromatin. Here we show that complex satDNAs (>100-bp repeat units) are transcribed into long noncoding RNAs and processed into piRNAs (PIWI interacting RNAs). This satDNA piRNA production depends on the Rhino-Deadlock-Cutoff complex and the transcription factor Moonshiner-a previously described non-canonical pathway that licenses heterochromatin-dependent transcription of dual-strand piRNA clusters. We show that this pathway is important for establishing heterochromatin at satDNAs. Therefore, satDNAs are regulated by piRNAs originating from their own genomic loci. This novel mechanism of satDNA regulation provides insight into the role of piRNA pathways in heterochromatin formation and genome stability.
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Affiliation(s)
- Xiaolu Wei
- Department of Biomedical Genetics, University of Rochester Medical CenterRochesterUnited States
| | - Danna G Eickbush
- Department of Biology, University of RochesterRochesterUnited States
| | - Iain Speece
- Department of Biology, University of RochesterRochesterUnited States
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37
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Fabry MH, Falconio FA, Joud F, Lythgoe EK, Czech B, Hannon GJ. Maternally inherited piRNAs direct transient heterochromatin formation at active transposons during early Drosophila embryogenesis. eLife 2021; 10:e68573. [PMID: 34236313 PMCID: PMC8352587 DOI: 10.7554/elife.68573] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Accepted: 07/07/2021] [Indexed: 12/12/2022] Open
Abstract
The PIWI-interacting RNA (piRNA) pathway controls transposon expression in animal germ cells, thereby ensuring genome stability over generations. In Drosophila, piRNAs are intergenerationally inherited through the maternal lineage, and this has demonstrated importance in the specification of piRNA source loci and in silencing of I- and P-elements in the germ cells of daughters. Maternally inherited Piwi protein enters somatic nuclei in early embryos prior to zygotic genome activation and persists therein for roughly half of the time required to complete embryonic development. To investigate the role of the piRNA pathway in the embryonic soma, we created a conditionally unstable Piwi protein. This enabled maternally deposited Piwi to be cleared from newly laid embryos within 30 min and well ahead of the activation of zygotic transcription. Examination of RNA and protein profiles over time, and correlation with patterns of H3K9me3 deposition, suggests a role for maternally deposited Piwi in attenuating zygotic transposon expression in somatic cells of the developing embryo. In particular, robust deposition of piRNAs targeting roo, an element whose expression is mainly restricted to embryonic development, results in the deposition of transient heterochromatic marks at active roo insertions. We hypothesize that roo, an extremely successful mobile element, may have adopted a lifestyle of expression in the embryonic soma to evade silencing in germ cells.
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Affiliation(s)
- Martin H Fabry
- CRUK Cambridge Institute, University of Cambridge, Li Ka Shing CentreCambridgeUnited Kingdom
| | - Federica A Falconio
- CRUK Cambridge Institute, University of Cambridge, Li Ka Shing CentreCambridgeUnited Kingdom
| | - Fadwa Joud
- CRUK Cambridge Institute, University of Cambridge, Li Ka Shing CentreCambridgeUnited Kingdom
| | - Emily K Lythgoe
- CRUK Cambridge Institute, University of Cambridge, Li Ka Shing CentreCambridgeUnited Kingdom
| | - Benjamin Czech
- CRUK Cambridge Institute, University of Cambridge, Li Ka Shing CentreCambridgeUnited Kingdom
| | - Gregory J Hannon
- CRUK Cambridge Institute, University of Cambridge, Li Ka Shing CentreCambridgeUnited Kingdom
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38
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Shapiro-Kulnane L, Bautista O, Salz HK. An RNA-interference screen in Drosophila to identify ZAD-containing C2H2 zinc finger genes that function in female germ cells. G3-GENES GENOMES GENETICS 2021; 11:6025177. [PMID: 33561227 PMCID: PMC8022714 DOI: 10.1093/g3journal/jkaa016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Accepted: 11/14/2020] [Indexed: 11/24/2022]
Abstract
The zinc finger-associated domain (ZAD) is present in over 90 C2H2 zinc finger (ZNF) proteins. Despite their abundance, only a few ZAD-ZNF genes have been characterized to date. Here, we systematically analyze the function of 68 ZAD-ZNF genes in Drosophila female germ cells by performing an in vivo RNA-interference screen. We identified eight ZAD-ZNF genes required for oogenesis, and based on further characterization of the knockdown phenotypes, we uncovered defects broadly consistent with functions in germ cell specification and/or survival, early differentiation, and egg chamber maturation. These results provide a candidate pool for future studies aimed at functionalization of this large but poorly characterized gene family.
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Affiliation(s)
- Laura Shapiro-Kulnane
- Department of Genetics and Genome Sciences, Case Western Reserve University, School of Medicine, 10900 Euclid Ave. Cleveland, OH 44106, USA
| | - Oscar Bautista
- Department of Genetics and Genome Sciences, Case Western Reserve University, School of Medicine, 10900 Euclid Ave. Cleveland, OH 44106, USA
| | - Helen K Salz
- Department of Genetics and Genome Sciences, Case Western Reserve University, School of Medicine, 10900 Euclid Ave. Cleveland, OH 44106, USA
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39
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Joosten J, Taşköprü E, Jansen PWTC, Pennings B, Vermeulen M, Van Rij RP. PIWI proteomics identifies Atari and Pasilla as piRNA biogenesis factors in Aedes mosquitoes. Cell Rep 2021; 35:109073. [PMID: 33951430 DOI: 10.1016/j.celrep.2021.109073] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 03/03/2021] [Accepted: 04/12/2021] [Indexed: 01/29/2023] Open
Abstract
As in most arthropods, the PIWI-interacting RNA (piRNA) pathway in the vector mosquito Aedes aegypti is active in diverse biological processes in both soma and germline. To gain insights into piRNA biogenesis and effector complexes, we mapped the interactomes of the somatic PIWI proteins Ago3, Piwi4, Piwi5, and Piwi6 and identify numerous specific interactors as well as cofactors associated with multiple PIWI proteins. We describe the Piwi5 interactor AAEL014965, the direct ortholog of the Drosophila splicing factor pasilla. We find that Ae. aegypti Pasilla encodes a nuclear isoform and a cytoplasmic isoform, the latter of which is required for efficient piRNA production. In addition, we characterize a splice variant of the Tudor protein AAEL008101/Atari that associates with Ago3 and forms a scaffold for PIWI proteins and target RNAs to promote ping-pong amplification of piRNAs. Our study provides a useful resource for follow-up studies of somatic piRNA biogenesis, mechanism, and function in Aedes mosquitoes.
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Affiliation(s)
- Joep Joosten
- Department of Medical Microbiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, P.O. Box 9101, 6500 HB Nijmegen, the Netherlands
| | - Ezgi Taşköprü
- Department of Medical Microbiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, P.O. Box 9101, 6500 HB Nijmegen, the Netherlands
| | - Pascal W T C Jansen
- Department of Molecular Biology, Faculty of Science, Radboud Institute for Molecular Life Sciences, Oncode Institute, Radboud University Nijmegen, 6525 GA Nijmegen, the Netherlands
| | - Bas Pennings
- Department of Medical Microbiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, P.O. Box 9101, 6500 HB Nijmegen, the Netherlands
| | - Michiel Vermeulen
- Department of Molecular Biology, Faculty of Science, Radboud Institute for Molecular Life Sciences, Oncode Institute, Radboud University Nijmegen, 6525 GA Nijmegen, the Netherlands
| | - Ronald P Van Rij
- Department of Medical Microbiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, P.O. Box 9101, 6500 HB Nijmegen, the Netherlands.
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40
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Munafò M, Lawless VR, Passera A, MacMillan S, Bornelöv S, Haussmann IU, Soller M, Hannon GJ, Czech B. Channel nuclear pore complex subunits are required for transposon silencing in Drosophila. eLife 2021; 10:e66321. [PMID: 33856346 PMCID: PMC8133776 DOI: 10.7554/elife.66321] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Accepted: 04/14/2021] [Indexed: 12/21/2022] Open
Abstract
The nuclear pore complex (NPC) is the principal gateway between nucleus and cytoplasm that enables exchange of macromolecular cargo. Composed of multiple copies of ~30 different nucleoporins (Nups), the NPC acts as a selective portal, interacting with factors which individually license passage of specific cargo classes. Here we show that two Nups of the inner channel, Nup54 and Nup58, are essential for transposon silencing via the PIWI-interacting RNA (piRNA) pathway in the Drosophila ovary. In ovarian follicle cells, loss of Nup54 and Nup58 results in compromised piRNA biogenesis exclusively from the flamenco locus, whereas knockdowns of other NPC subunits have widespread consequences. This provides evidence that some Nups can acquire specialised roles in tissue-specific contexts. Our findings consolidate the idea that the NPC has functions beyond simply constituting a barrier to nuclear/cytoplasmic exchange as genomic loci subjected to strong selective pressure can exploit NPC subunits to facilitate their expression.
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Affiliation(s)
- Marzia Munafò
- Cancer Research UK Cambridge Institute, University of Cambridge, Li Ka Shing CentreCambridgeUnited Kingdom
| | - Victoria R Lawless
- Cancer Research UK Cambridge Institute, University of Cambridge, Li Ka Shing CentreCambridgeUnited Kingdom
| | - Alessandro Passera
- Cancer Research UK Cambridge Institute, University of Cambridge, Li Ka Shing CentreCambridgeUnited Kingdom
| | - Serena MacMillan
- Cancer Research UK Cambridge Institute, University of Cambridge, Li Ka Shing CentreCambridgeUnited Kingdom
| | - Susanne Bornelöv
- Cancer Research UK Cambridge Institute, University of Cambridge, Li Ka Shing CentreCambridgeUnited Kingdom
| | - Irmgard U Haussmann
- Department of Life Science, Faculty of Health, Education and Life Sciences, Birmingham City UniversityBirminghamUnited Kingdom
- School of Biosciences, College of Life and Environmental Sciences, University of BirminghamBirminghamUnited Kingdom
| | - Matthias Soller
- School of Biosciences, College of Life and Environmental Sciences, University of BirminghamBirminghamUnited Kingdom
- Birmingham Center for Genome Biology, University of BirminghamBirminghamUnited Kingdom
| | - Gregory J Hannon
- Cancer Research UK Cambridge Institute, University of Cambridge, Li Ka Shing CentreCambridgeUnited Kingdom
| | - Benjamin Czech
- Cancer Research UK Cambridge Institute, University of Cambridge, Li Ka Shing CentreCambridgeUnited Kingdom
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41
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Schwarz F, Wierzbicki F, Senti KA, Kofler R. Tirant Stealthily Invaded Natural Drosophila melanogaster Populations during the Last Century. Mol Biol Evol 2021; 38:1482-1497. [PMID: 33247725 PMCID: PMC8042734 DOI: 10.1093/molbev/msaa308] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
It was long thought that solely three different transposable elements (TEs)-the I-element, the P-element, and hobo-invaded natural Drosophila melanogaster populations within the last century. By sequencing the "living fossils" of Drosophila research, that is, D. melanogaster strains sampled from natural populations at different time points, we show that a fourth TE, Tirant, invaded D. melanogaster populations during the past century. Tirant likely spread in D. melanogaster populations around 1938, followed by the I-element, hobo, and, lastly, the P-element. In addition to the recent insertions of the canonical Tirant, D. melanogaster strains harbor degraded Tirant sequences in the heterochromatin which are likely due to an ancient invasion, likely predating the split of D. melanogaster and D. simulans. These degraded insertions produce distinct piRNAs that were unable to prevent the novel Tirant invasion. In contrast to the I-element, P-element, and hobo, we did not find that Tirant induces any hybrid dysgenesis symptoms. This absence of apparent phenotypic effects may explain the late discovery of the Tirant invasion. Recent Tirant insertions were found in all investigated natural populations. Populations from Tasmania carry distinct Tirant sequences, likely due to a founder effect. By investigating the TE composition of natural populations and strains sampled at different time points, insertion site polymorphisms, piRNAs, and phenotypic effects, we provide a comprehensive study of a natural TE invasion.
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Affiliation(s)
- Florian Schwarz
- Institut für Populationsgenetik, Vetmeduni Vienna, Vienna, Austria
- Vienna Graduate School of Population Genetics, Vetmeduni Vienna, Vienna, Austria
| | - Filip Wierzbicki
- Institut für Populationsgenetik, Vetmeduni Vienna, Vienna, Austria
- Vienna Graduate School of Population Genetics, Vetmeduni Vienna, Vienna, Austria
| | | | - Robert Kofler
- Institut für Populationsgenetik, Vetmeduni Vienna, Vienna, Austria
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42
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HSP70/DNAJ Family of Genes in the Brown Planthopper, Nilaparvata lugens: Diversity and Function. Genes (Basel) 2021; 12:genes12030394. [PMID: 33801945 PMCID: PMC7999391 DOI: 10.3390/genes12030394] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Revised: 03/02/2021] [Accepted: 03/08/2021] [Indexed: 02/07/2023] Open
Abstract
Heat shock 70kDa proteins (HSP70s) and their cochaperones DNAJs are ubiquitous molecular chaperones, which function as the “HSP70/DNAJ machinery” in a myriad of biological processes. At present, a number of HSP70s have been classified in many species, but studies on DNAJs, especially in insects, are lacking. Here, we first systematically identified and characterized the HSP70 and DNAJ family members in the brown planthopper (BPH), Nilaparvata lugens, a destructive rice pest in Asia. A total of nine HSP70 and 31 DNAJ genes were identified in the BPH genome. Sequence and phylogenetic analyses revealed the high diversity of the NlDNAJ family. Additionally, spatio-temporal expression analysis showed that most NlHSP70 and NlDNAJ genes were highly expressed in the adult stage and gonads. Furthermore, RNA interference (RNAi) revealed that seven NlHSP70s and 10 NlDNAJs play indispensable roles in the nymphal development, oogenesis, and female fertility of N. lugens under physiological growth conditions; in addition, one HSP70 (NlHSP68) was found to be important in the thermal tolerance of eggs. Together, our results in this study shed more light on the biological roles of HSP70/DNAJ in regulating life cycle, coping with environmental stresses, and mediating the interactions within, or between, the two gene families in insects.
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43
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Ipsaro JJ, O'Brien PA, Bhattacharya S, Palmer AG, Joshua-Tor L. Asterix/Gtsf1 links tRNAs and piRNA silencing of retrotransposons. Cell Rep 2021; 34:108914. [PMID: 33789107 DOI: 10.1016/j.celrep.2021.108914] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 01/15/2021] [Accepted: 03/05/2021] [Indexed: 02/05/2023] Open
Abstract
The Piwi-interacting RNA (piRNA) pathway safeguards genomic integrity by silencing transposable elements (transposons) in the germline. While Piwi is the central piRNA factor, others including Asterix/Gtsf1 have also been demonstrated to be critical for effective silencing. Here, using enhanced crosslinking and immunoprecipitation (eCLIP) with a custom informatic pipeline, we show that Asterix/Gtsf1 specifically binds tRNAs in cellular contexts. We determined the structure of mouse Gtsf1 by NMR spectroscopy and identified the RNA-binding interface on the protein's first zinc finger, which was corroborated by biochemical analysis as well as cryo-EM structures of Gtsf1 in complex with co-purifying tRNA. Consistent with the known dependence of long terminal repeat (LTR) retrotransposons on tRNA primers, we demonstrate that LTR retrotransposons are, in fact, preferentially de-repressed in Asterix mutants. Together, these findings link Asterix/Gtsf1, tRNAs, and LTR retrotransposon silencing and suggest that Asterix exploits tRNA dependence to identify transposon transcripts and promote piRNA silencing.
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Affiliation(s)
- Jonathan J Ipsaro
- Howard Hughes Medical Institute, W.M. Keck Structural Biology Laboratory, Cold Spring Harbor Laboratory, 1 Bungtown Road, Cold Spring Harbor, NY 11724, USA
| | - Paul A O'Brien
- Department of Biochemistry and Molecular Biophysics, Columbia University Medical Center, 650 West 168th Street, New York, NY 10032, USA
| | | | - Arthur G Palmer
- Department of Biochemistry and Molecular Biophysics, Columbia University Medical Center, 650 West 168th Street, New York, NY 10032, USA
| | - Leemor Joshua-Tor
- Howard Hughes Medical Institute, W.M. Keck Structural Biology Laboratory, Cold Spring Harbor Laboratory, 1 Bungtown Road, Cold Spring Harbor, NY 11724, USA.
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44
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Beltran T, Pahita E, Ghosh S, Lenhard B, Sarkies P. Integrator is recruited to promoter-proximally paused RNA Pol II to generate Caenorhabditis elegans piRNA precursors. EMBO J 2021; 40:e105564. [PMID: 33340372 PMCID: PMC7917550 DOI: 10.15252/embj.2020105564] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 10/14/2020] [Accepted: 10/27/2020] [Indexed: 12/29/2022] Open
Abstract
Piwi-interacting RNAs (piRNAs) play key roles in germline development and genome defence in metazoans. In C. elegans, piRNAs are transcribed from > 15,000 discrete genomic loci by RNA polymerase II (Pol II), resulting in 28 nt short-capped piRNA precursors. Here, we investigate transcription termination at piRNA loci. We show that the Integrator complex, which terminates snRNA transcription, is recruited to piRNA loci. Moreover, we demonstrate that the catalytic activity of Integrator cleaves nascent capped piRNA precursors associated with promoter-proximal Pol II, resulting in termination of transcription. Loss of Integrator activity, however, does not result in transcriptional readthrough at the majority of piRNA loci. Taken together, our results draw new parallels between snRNA and piRNA biogenesis in nematodes and provide evidence of a role for the Integrator complex as a terminator of promoter-proximal RNA polymerase II during piRNA biogenesis.
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Affiliation(s)
- Toni Beltran
- MRC London Institute of Medical SciencesLondonUK
- Institute of Clinical SciencesImperial College LondonLondonUK
- Present address:
Centre for Genomic RegulationBarcelonaSpain
| | - Elena Pahita
- MRC London Institute of Medical SciencesLondonUK
- Institute of Clinical SciencesImperial College LondonLondonUK
| | - Subhanita Ghosh
- MRC London Institute of Medical SciencesLondonUK
- Institute of Clinical SciencesImperial College LondonLondonUK
| | - Boris Lenhard
- MRC London Institute of Medical SciencesLondonUK
- Institute of Clinical SciencesImperial College LondonLondonUK
| | - Peter Sarkies
- MRC London Institute of Medical SciencesLondonUK
- Institute of Clinical SciencesImperial College LondonLondonUK
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45
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Eastwood EL, Jara KA, Bornelöv S, Munafò M, Frantzis V, Kneuss E, Barbar EJ, Czech B, Hannon GJ. Dimerisation of the PICTS complex via LC8/Cut-up drives co-transcriptional transposon silencing in Drosophila. eLife 2021; 10:e65557. [PMID: 33538693 PMCID: PMC7861614 DOI: 10.7554/elife.65557] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Accepted: 01/04/2021] [Indexed: 12/16/2022] Open
Abstract
In animal gonads, the PIWI-interacting RNA (piRNA) pathway guards genome integrity in part through the co-transcriptional gene silencing of transposon insertions. In Drosophila ovaries, piRNA-loaded Piwi detects nascent transposon transcripts and instructs heterochromatin formation through the Panoramix-induced co-transcriptional silencing (PICTS) complex, containing Panoramix, Nxf2 and Nxt1. Here, we report that the highly conserved dynein light chain LC8/Cut-up (Ctp) is an essential component of the PICTS complex. Loss of Ctp results in transposon de-repression and a reduction in repressive chromatin marks specifically at transposon loci. In turn, Ctp can enforce transcriptional silencing when artificially recruited to RNA and DNA reporters. We show that Ctp drives dimerisation of the PICTS complex through its interaction with conserved motifs within Panoramix. Artificial dimerisation of Panoramix bypasses the necessity for its interaction with Ctp, demonstrating that conscription of a protein from a ubiquitous cellular machinery has fulfilled a fundamental requirement for a transposon silencing complex.
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Affiliation(s)
- Evelyn L Eastwood
- Cancer Research UK Cambridge Institute, University of Cambridge, Li Ka Shing CentreCambridgeUnited Kingdom
| | - Kayla A Jara
- Department of Biochemistry and Biophysics, Oregon State UniversityCorvallisUnited States
| | - Susanne Bornelöv
- Cancer Research UK Cambridge Institute, University of Cambridge, Li Ka Shing CentreCambridgeUnited Kingdom
| | - Marzia Munafò
- Cancer Research UK Cambridge Institute, University of Cambridge, Li Ka Shing CentreCambridgeUnited Kingdom
| | - Vasileios Frantzis
- Cancer Research UK Cambridge Institute, University of Cambridge, Li Ka Shing CentreCambridgeUnited Kingdom
| | - Emma Kneuss
- Cancer Research UK Cambridge Institute, University of Cambridge, Li Ka Shing CentreCambridgeUnited Kingdom
| | - Elisar J Barbar
- Department of Biochemistry and Biophysics, Oregon State UniversityCorvallisUnited States
| | - Benjamin Czech
- Cancer Research UK Cambridge Institute, University of Cambridge, Li Ka Shing CentreCambridgeUnited Kingdom
| | - Gregory J Hannon
- Cancer Research UK Cambridge Institute, University of Cambridge, Li Ka Shing CentreCambridgeUnited Kingdom
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46
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Tsai SY, Huang F. Acetyltransferase Enok regulates transposon silencing and piRNA cluster transcription. PLoS Genet 2021; 17:e1009349. [PMID: 33524038 PMCID: PMC7877743 DOI: 10.1371/journal.pgen.1009349] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 02/11/2021] [Accepted: 01/07/2021] [Indexed: 11/19/2022] Open
Abstract
The piRNA pathway is a highly conserved mechanism to repress transposon activation in the germline in Drosophila and mammals. This pathway starts from transcribing piRNA clusters to generate long piRNA precursors. The majority of piRNA clusters lack conventional promoters, and utilize heterochromatin- and HP1D/Rhino-dependent noncanonical mechanisms for transcription. However, information regarding the transcriptional regulation of piRNA clusters is limited. Here, we report that the Drosophila acetyltransferase Enok, which can activate transcription by acetylating H3K23, is critical for piRNA production from 54% of piRNA clusters including 42AB, the major piRNA source. Surprisingly, we found that Enok not only promotes rhino expression by acetylating H3K23, but also directly enhances transcription of piRNA clusters by facilitating Rhino recruitment. Taken together, our study provides novel insights into the regulation of noncanonical transcription at piRNA clusters and transposon silencing. Roughly half of our genome is composed of transposons. Activation of those transposons in the germline will result in severe DNA damages and infertility. The PIWI-interacting RNA (piRNA) pathway, which is highly conserved between mammals and flies, is a key mechanism to suppress transposon activation in the germline. Here, we identified the fly acetyltransferase Enok as a novel regulator functioning in the early steps of this pathway. We found that Enok can promote the expression of three genes involved in piRNA production by acetylating histone H3 lysine 23 (H3K23). We also demonstrated that Enok regulates the recruitment of Rhi, a factor critical for transcription initiation at piRNA-generating loci, to a subset of those loci, and therefore enhances their transcription. Our findings reveal an upstream regulator in the piRNA pathway and advance our understanding regarding the molecular mechanism of transposon silencing.
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Affiliation(s)
- Shih-Ying Tsai
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Fu Huang
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
- * E-mail:
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47
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Saint-Leandre B, Christopher C, Levine MT. Adaptive evolution of an essential telomere protein restricts telomeric retrotransposons. eLife 2020; 9:e60987. [PMID: 33350936 PMCID: PMC7755394 DOI: 10.7554/elife.60987] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Accepted: 11/02/2020] [Indexed: 02/06/2023] Open
Abstract
Essential, conserved cellular processes depend not only on essential, strictly conserved proteins but also on essential proteins that evolve rapidly. To probe this poorly understood paradox, we exploited the rapidly evolving Drosophila telomere-binding protein, cav/HOAP, which protects chromosomes from lethal end-to-end fusions. We replaced the D. melanogaster HOAP with a highly diverged version from its close relative, D. yakuba. The D. yakuba HOAP ('HOAP[yak]') localizes to D. melanogaster telomeres and protects D. melanogaster chromosomes from fusions. However, HOAP[yak] fails to rescue a previously uncharacterized HOAP function: silencing of the specialized telomeric retrotransposons that, instead of telomerase, maintain chromosome length in Drosophila. Whole genome sequencing and cytogenetics of experimentally evolved populations revealed that HOAP[yak] triggers telomeric retrotransposon proliferation, resulting in aberrantly long telomeres. This evolution-generated, separation-of-function allele resolves the paradoxical observation that a fast-evolving essential gene directs an essential, strictly conserved function: telomeric retrotransposon containment, not end-protection, requires evolutionary innovation at HOAP.
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Affiliation(s)
- Bastien Saint-Leandre
- Department of Biology and Epigenetics Institute, University of PennsylvaniaPhiladelphiaUnited States
| | - Courtney Christopher
- Department of Biology and Epigenetics Institute, University of PennsylvaniaPhiladelphiaUnited States
| | - Mia T Levine
- Department of Biology and Epigenetics Institute, University of PennsylvaniaPhiladelphiaUnited States
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48
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Ellison CE, Kagda MS, Cao W. Telomeric TART elements target the piRNA machinery in Drosophila. PLoS Biol 2020; 18:e3000689. [PMID: 33347429 PMCID: PMC7785250 DOI: 10.1371/journal.pbio.3000689] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 01/05/2021] [Accepted: 12/10/2020] [Indexed: 11/23/2022] Open
Abstract
Coevolution between transposable elements (TEs) and their hosts can be antagonistic, where TEs evolve to avoid silencing and the host responds by reestablishing TE suppression, or mutualistic, where TEs are co-opted to benefit their host. The TART-A TE functions as an important component of Drosophila telomeres but has also reportedly inserted into the Drosophila melanogaster nuclear export factor gene nxf2. We find that, rather than inserting into nxf2, TART-A has actually captured a portion of nxf2 sequence. We show that TART-A produces abundant Piwi-interacting small RNAs (piRNAs), some of which are antisense to the nxf2 transcript, and that the TART-like region of nxf2 is evolving rapidly. Furthermore, in D. melanogaster, TART-A is present at higher copy numbers, and nxf2 shows reduced expression, compared to the closely related species Drosophila simulans. We propose that capturing nxf2 sequence allowed TART-A to target the nxf2 gene for piRNA-mediated repression and that these 2 elements are engaged in antagonistic coevolution despite the fact that TART-A is serving a critical role for its host genome. Co-evolution between transposable elements (TEs) and their hosts can be antagonistic, where TEs evolve to avoid silencing and the host responds by re-establishing TE suppression, or mutualistic, where TEs are co-opted to benefit their host. This study shows that a specialized Drosophila retrotransposon that functions as a telomere has captured a portion of a host piRNA gene which may allow it to evade silencing.
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Affiliation(s)
- Christopher E. Ellison
- Department of Genetics, Human Genetics Institute of New Jersey, Rutgers, The State University of New Jersey, Piscataway, New Jersey, United States of America
- * E-mail:
| | - Meenakshi S. Kagda
- Department of Genetics, Human Genetics Institute of New Jersey, Rutgers, The State University of New Jersey, Piscataway, New Jersey, United States of America
| | - Weihuan Cao
- Department of Genetics, Human Genetics Institute of New Jersey, Rutgers, The State University of New Jersey, Piscataway, New Jersey, United States of America
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49
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Kasinathan B, Colmenares SU, McConnell H, Young JM, Karpen GH, Malik HS. Innovation of heterochromatin functions drives rapid evolution of essential ZAD-ZNF genes in Drosophila. eLife 2020; 9:e63368. [PMID: 33169670 PMCID: PMC7655104 DOI: 10.7554/elife.63368] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Accepted: 10/12/2020] [Indexed: 12/12/2022] Open
Abstract
Contrary to dogma, evolutionarily young and dynamic genes can encode essential functions. We find that evolutionarily dynamic ZAD-ZNF genes, which encode the most abundant class of insect transcription factors, are more likely to encode essential functions in Drosophila melanogaster than ancient, conserved ZAD-ZNF genes. We focus on the Nicknack ZAD-ZNF gene, which is evolutionarily young, poorly retained in Drosophila species, and evolves under strong positive selection. Yet we find that it is necessary for larval development in D. melanogaster. We show that Nicknack encodes a heterochromatin-localizing protein like its paralog Oddjob, also an evolutionarily dynamic yet essential ZAD-ZNF gene. We find that the divergent D. simulans Nicknack protein can still localize to D. melanogaster heterochromatin and rescue viability of female but not male Nicknack-null D. melanogaster. Our findings suggest that innovation for rapidly changing heterochromatin functions might generally explain the essentiality of many evolutionarily dynamic ZAD-ZNF genes in insects.
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Affiliation(s)
- Bhavatharini Kasinathan
- Medical Scientist Training Program, University of Washington School of MedicineSeattleUnited States
- Molecular and Cellular Biology Graduate program, University of Washington School of MedicineSeattleUnited States
- Division of Basic Sciences, Fred Hutchinson Cancer Research CenterSeattleUnited States
| | - Serafin U Colmenares
- Biological Systems and Engineering Division, Lawrence Berkeley National LaboratoryBerkeleyUnited States
- Department of Molecular and Cell Biology, University of California at BerkeleyBerkeleyUnited States
- Innovative Genomics InstituteBerkeleyUnited States
| | - Hannah McConnell
- Division of Basic Sciences, Fred Hutchinson Cancer Research CenterSeattleUnited States
| | - Janet M Young
- Division of Basic Sciences, Fred Hutchinson Cancer Research CenterSeattleUnited States
| | - Gary H Karpen
- Biological Systems and Engineering Division, Lawrence Berkeley National LaboratoryBerkeleyUnited States
- Department of Molecular and Cell Biology, University of California at BerkeleyBerkeleyUnited States
- Innovative Genomics InstituteBerkeleyUnited States
| | - Harmit S Malik
- Division of Basic Sciences, Fred Hutchinson Cancer Research CenterSeattleUnited States
- Howard Hughes Medical Institute, Fred Hutchinson Cancer Research CenterSeattleUnited States
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50
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Gamez S, Srivastav S, Akbari OS, Lau NC. Diverse Defenses: A Perspective Comparing Dipteran Piwi-piRNA Pathways. Cells 2020; 9:E2180. [PMID: 32992598 PMCID: PMC7601171 DOI: 10.3390/cells9102180] [Citation(s) in RCA: 8] [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: 09/02/2020] [Revised: 09/22/2020] [Accepted: 09/23/2020] [Indexed: 02/07/2023] Open
Abstract
Animals face the dual threat of virus infections hijacking cellular function and transposons proliferating in germline genomes. For insects, the deeply conserved RNA interference (RNAi) pathways and other chromatin regulators provide an important line of defense against both viruses and transposons. For example, this innate immune system displays adaptiveness to new invasions by generating cognate small RNAs for targeting gene silencing measures against the viral and genomic intruders. However, within the Dipteran clade of insects, Drosophilid fruit flies and Culicids mosquitoes have evolved several unique mechanistic aspects of their RNAi defenses to combat invading transposons and viruses, with the Piwi-piRNA arm of the RNAi pathways showing the greatest degree of novel evolution. Whereas central features of Piwi-piRNA pathways are conserved between Drosophilids and Culicids, multiple lineage-specific innovations have arisen that may reflect distinct genome composition differences and specific ecological and physiological features dividing these two branches of Dipterans. This perspective review focuses on the most recent findings illuminating the Piwi/piRNA pathway distinctions between fruit flies and mosquitoes, and raises open questions that need to be addressed in order to ameliorate human diseases caused by pathogenic viruses that mosquitoes transmit as vectors.
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Affiliation(s)
- Stephanie Gamez
- Division of Biological Sciences, Section of Cell and Developmental Biology, University of California, San Diego, CA 92093, USA; (S.G.); (O.S.A.)
| | - Satyam Srivastav
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853-2703, USA;
| | - Omar S. Akbari
- Division of Biological Sciences, Section of Cell and Developmental Biology, University of California, San Diego, CA 92093, USA; (S.G.); (O.S.A.)
| | - Nelson C. Lau
- Department of Biochemistry and Genome Science Institute, Boston University School of Medicine, Boston, MA 02118, USA
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