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Kazmi I, Altamimi ASA, Afzal M, Majami AA, Abbasi FA, Almalki WH, Alzera SI, Kukreti N, Fuloria NK, Fuloria S, Sekar M, Abida. Non-coding RNAs: Emerging biomarkers and therapeutic targets in ulcerative colitis. Pathol Res Pract 2024; 253:155037. [PMID: 38160482 DOI: 10.1016/j.prp.2023.155037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/18/2023] [Revised: 12/10/2023] [Accepted: 12/11/2023] [Indexed: 01/03/2024]
Abstract
Ulcerative colitis (UC) is a persistent inflammatory condition affecting the colon's mucosal lining, leading to chronic bowel inflammation. Despite extensive research, the precise molecular mechanisms underlying UC pathogenesis remain elusive. NcRNAs form a category of functional RNA molecules devoid of protein-coding capacity. They have recently surfaced as pivotal modulators of gene expression and integral participants in various pathological processes, particularly those related to inflammatory disorders. The diverse classes of ncRNAs, encompassing miRNAs, circRNAs, and lncRNAs, have been implicated in UC. It highlights their involvement in key UC-related processes, such as immune cell activation, epithelial barrier integrity, and the production of pro-inflammatory mediators. ncRNAs have been identified as potential biomarkers for UC diagnosis and monitoring disease progression, offering promising avenues for personalized medicine. This approach may pave the way for novel, more specific treatments with reduced side effects, addressing the current limitations of conventional therapies. A comprehensive understanding of the interplay between ncRNAs and UC will advance our knowledge of the disease, potentially leading to more effective and personalized treatments for patients suffering from this debilitating condition. This review explores the pivotal role of ncRNAs in the context of UC, shedding light on their possible targets for diagnosis, prognosis, and therapeutic interventions.
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Affiliation(s)
- Imran Kazmi
- Department of Biochemistry, Faculty of Science, King Abdulaziz University, Jeddah 21589, Saudi Arabia
| | | | - Muhammad Afzal
- Department of Pharmaceutical Sciences, Pharmacy Program, Batterjee Medical College, P.O. Box 6231, Jeddah 21442, Saudi Arabia
| | - Abdullah A Majami
- Department of Biochemistry, Faculty of Science, King Abdulaziz University, Jeddah 21589, Saudi Arabia
| | - Fahad Al Abbasi
- Department of Biochemistry, Faculty of Science, King Abdulaziz University, Jeddah 21589, Saudi Arabia
| | - Waleed Hassan Almalki
- Department of Pharmacology, College of Pharmacy, Umm Al-Qura University, Makkah, Saudi Arabia
| | - Sami I Alzera
- Department of Pharmacology, College of Pharmacy, Jouf University, Sakaka 72341, Al-Jouf, Saudi Arabia
| | - Neelima Kukreti
- School of Pharmacy, Graphic Era Hill University, Dehradun 248007, India
| | | | - Shivkanya Fuloria
- Faculty of Pharmacy, AIMST University, Bedong 08100, Kedah, Malaysia
| | - Mahendran Sekar
- School of Pharmacy, Monash University Malaysia, Bandar Sunway, Subang Jaya 47500, Selangor, Malaysia
| | - Abida
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Northern Border University, Rafha 91911, Saudi Arabia
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Yeh SC, Diosa-Toro M, Tan WL, Rachenne F, Hain A, Yeo CPX, Bribes I, Xiang BWW, Sathiamoorthy Kannan G, Manuel MC, Missé D, Mok YK, Pompon J. Characterization of dengue virus 3'UTR RNA binding proteins in mosquitoes reveals that AeStaufen reduces subgenomic flaviviral RNA in saliva. PLoS Pathog 2022; 18:e1010427. [PMID: 36121894 PMCID: PMC9531803 DOI: 10.1371/journal.ppat.1010427] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Revised: 10/04/2022] [Accepted: 09/09/2022] [Indexed: 11/27/2022] Open
Abstract
Dengue viruses (DENV) are expanding global pathogens that are transmitted through the bite of mosquitoes, mostly Aedes aegypti. As RNA viruses, DENV rely on RNA-binding proteins (RBPs) to complete their life cycle. Alternatively, RBPs can act as restriction factors that prevent DENV multiplication. While the importance of RBPs is well-supported in humans, there is a dearth of information about their influence on DENV transmission by mosquitoes. Such knowledge could be harnessed to design novel, effective interventions against DENV. Here, we successfully adapted RNA-affinity chromatography coupled with mass spectrometry-a technique initially developed in mammalian cells-to identify RBPs in Ae. aegypti cells. We identified fourteen RBPs interacting with DENV serotype 2 3'UTR, which is involved in the viral multiplication and produces subgenomic flaviviral RNA (sfRNA). We validated the RNA affinity results for two RBPs by confirming that AePur binds the 3'UTR, whereas AeStaufen interacts with both 3'UTR and sfRNA. Using in vivo functional evaluation, we determined that RBPs like AeRan, AeExoRNase, and AeRNase have pro-viral functions, whereas AeGTPase, AeAtu, and AePur have anti-viral functions in mosquitoes. Furthermore, we showed that human and mosquito Pur homologs have a shared affinity to DENV2 RNA, although the anti-viral effect is specific to the mosquito protein. Importantly, we revealed that AeStaufen mediates a reduction of gRNA and sfRNA copies in several mosquito tissues, including the salivary glands and that AeStaufen-mediated sfRNA reduction diminishes the concentration of transmission-enhancing sfRNA in saliva, thereby revealing AeStaufen's role in DENV transmission. By characterizing the first RBPs that associate with DENV2 3'UTR in mosquitoes, our study unravels new pro- and anti-viral targets for the design of novel therapeutic interventions as well as provides foundation for studying the role of RBPs in virus-vector interactions.
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Affiliation(s)
- Shih-Chia Yeh
- Programme in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore, Republic of Singapore
| | - Mayra Diosa-Toro
- Programme in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore, Republic of Singapore
| | - Wei-Lian Tan
- Programme in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore, Republic of Singapore
| | | | - Arthur Hain
- Programme in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore, Republic of Singapore
| | - Celestia Pei Xuan Yeo
- Programme in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore, Republic of Singapore
| | - Inès Bribes
- MIVEGEC, Univ. Montpellier, IRD, CNRS, Montpellier, France
| | - Benjamin Wong Wei Xiang
- Programme in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore, Republic of Singapore
| | | | - Menchie Casayuran Manuel
- Programme in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore, Republic of Singapore
| | - Dorothée Missé
- MIVEGEC, Univ. Montpellier, IRD, CNRS, Montpellier, France
| | - Yu Keung Mok
- Department of Biological Sciences, National University of Singapore, Singapore, Republic of Singapore
| | - Julien Pompon
- Programme in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore, Republic of Singapore
- MIVEGEC, Univ. Montpellier, IRD, CNRS, Montpellier, France
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3
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Wang W, Zheng Q, Yu C, Pan C, Luo P, Chen J. WSV056 Inhibits Shrimp Nitric Oxide Synthase Activity by Downregulating Litopenaeus vannamei Sepiapterin Reductase to Promote White Spot Syndrome Virus Replication. Front Microbiol 2022; 12:796049. [PMID: 35003027 PMCID: PMC8733705 DOI: 10.3389/fmicb.2021.796049] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Accepted: 11/19/2021] [Indexed: 02/05/2023] Open
Abstract
Sepiapterin reductase (Spr) plays an essential role in the biosynthesis of tetrahydrobiopterin (BH4), a key cofactor of multiple enzymes involved in various physiological and immune processes. Suppression of Spr could result in BH4 deficiency-caused diseases in human and murine models. However, information on the biological function of Spr in invertebrates is limited. In this study, two Sprs (CG12116 and Sptr) from Drosophila melanogaster were found to be downregulated in transgenic flies overexpressing white spot syndrome virus (WSSV) immediate-early protein WSV056. CG12116 and Sptr exerted an inhibitory effect on the replication of the Drosophila C virus. A Litopenaeus vannamei Spr (LvSpr) exhibiting similarity of 64.1–67.5% and 57.3–62.2% to that of invertebrate and vertebrate Sprs, respectively, were cloned. L. vannamei challenged with WSSV revealed a significant decrease in LvSpr transcription and Spr activity in hemocytes. In addition, the BH4 co-factored nitric oxide synthase (Nos) activity in shrimp hemocytes was reduced in WSSV-infected and LvSpr knockdown shrimp, suggesting WSSV probably inhibits the LvNos activity through LvSpr downregulation to limit the production of nitric oxide (NO). Knockdown of LvSpr and LvNos caused the reduction in NO level in hemocytes and the increase of viral copy numbers in WSSV-infected shrimp. Supplementation of NO donor DETA/NO or double gene knockdown of WSV056 + LvSpr and WSV056 + LvNos recovered the NO production, whereas the WSSV copy numbers were decreased. Altogether, the findings demonstrated that LvSpr and LvNos could potentially inhibit WSSV. In turn, the virus has evolved to attenuate NO production via LvSpr suppression by WSV056, allowing evasion of host antiviral response to ensure efficient replication.
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Affiliation(s)
- Wei Wang
- Institute of Oceanography, Minjiang University, Fuzhou, China
| | - Qin Zheng
- Institute of Oceanography, Minjiang University, Fuzhou, China
| | - Chen Yu
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen, China
| | - Changkun Pan
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu, China
| | - Peng Luo
- CAS Key Laboratory of Tropical Marine Bio-Resources and Ecology (LMB), Guangdong Provincial Key Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China
| | - Jianming Chen
- Institute of Oceanography, Minjiang University, Fuzhou, China
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4
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Ullastres A, Merenciano M, González J. Regulatory regions in natural transposable element insertions drive interindividual differences in response to immune challenges in Drosophila. Genome Biol 2021; 22:265. [PMID: 34521452 PMCID: PMC8439047 DOI: 10.1186/s13059-021-02471-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Accepted: 08/19/2021] [Indexed: 02/08/2023] Open
Abstract
Background Variation in gene expression underlies interindividual variability in relevant traits including immune response. However, the genetic variation responsible for these gene expression changes remains largely unknown. Among the non-coding variants that could be relevant, transposable element insertions are promising candidates as they have been shown to be a rich and diverse source of cis-regulatory elements. Results In this work, we use a population genetics approach to identify transposable element insertions likely to increase the tolerance of Drosophila melanogaster to bacterial infection by affecting the expression of immune-related genes. We identify 12 insertions associated with allele-specific expression changes in immune-related genes. We experimentally validate three of these insertions including one likely to be acting as a silencer, one as an enhancer, and one with a dual role as enhancer and promoter. The direction in the change of gene expression associated with the presence of several of these insertions is consistent with an increased survival to infection. Indeed, for one of the insertions, we show that this is the case by analyzing both natural populations and CRISPR/Cas9 mutants in which the insertion is deleted from its native genomic context. Conclusions We show that transposable elements contribute to gene expression variation in response to infection in D. melanogaster and that this variation is likely to affect their survival capacity. Because the role of transposable elements as regulatory elements is not restricted to Drosophila, transposable elements are likely to play a role in immune response in other organisms as well. Supplementary Information The online version contains supplementary material available at 10.1186/s13059-021-02471-3.
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Affiliation(s)
- Anna Ullastres
- Institute of Evolutionary Biology (CSIC-Universitat Pompeu Fabra), Passeig Marítim de la Barceloneta 37-49, 08003, Barcelona, Spain
| | - Miriam Merenciano
- Institute of Evolutionary Biology (CSIC-Universitat Pompeu Fabra), Passeig Marítim de la Barceloneta 37-49, 08003, Barcelona, Spain
| | - Josefa González
- Institute of Evolutionary Biology (CSIC-Universitat Pompeu Fabra), Passeig Marítim de la Barceloneta 37-49, 08003, Barcelona, Spain.
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5
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Schneider J, Imler JL. Sensing and signalling viral infection in drosophila. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2021; 117:103985. [PMID: 33358662 DOI: 10.1016/j.dci.2020.103985] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 12/16/2020] [Accepted: 12/17/2020] [Indexed: 06/12/2023]
Abstract
The fruitfly Drosophila melanogaster is a valuable model to unravel mechanisms of innate immunity, in particular in the context of viral infections. RNA interference, and more specifically the small interfering RNA pathway, is a major component of antiviral immunity in drosophila. In addition, the contribution of inducible transcriptional responses to the control of viruses in drosophila and other invertebrates is increasingly recognized. In particular, the recent discovery of a STING-IKKβ-Relish signalling cassette in drosophila has confirmed that NF-κB transcription factors play an important role in the control of viral infections, in addition to bacterial and fungal infections. Here, we review recent developments in the field, which begin to shed light on the mechanisms involved in sensing of viral infections and in signalling leading to production of antiviral effectors.
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Affiliation(s)
- Juliette Schneider
- Université de Strasbourg, CNRS UPR9022, Institut de Biologie Moléculaire et Cellulaire, Strasbourg, France
| | - Jean-Luc Imler
- Université de Strasbourg, CNRS UPR9022, Institut de Biologie Moléculaire et Cellulaire, Strasbourg, France; Sino-French Hoffmann Institute, School of Basic Medical Science, Guangzhou Medical University, Guangzhou 511436, China.
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6
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Zhang L, Xu W, Gao X, Li W, Qi S, Guo D, Ajayi OE, Ding SW, Wu Q. lncRNA Sensing of a Viral Suppressor of RNAi Activates Non-canonical Innate Immune Signaling in Drosophila. Cell Host Microbe 2020; 27:115-128.e8. [PMID: 31917956 DOI: 10.1016/j.chom.2019.12.006] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Revised: 10/10/2019] [Accepted: 11/18/2019] [Indexed: 12/30/2022]
Abstract
Antiviral immunity in insects is mediated by the RNA interference (RNAi) pathway. Viruses evade antiviral RNAi by expressing virulence factors known as viral suppressors of RNAi (VSR). Here, we report the identification of VINR, a Drosophila VSR-interacting long non-coding (lnc) RNA that activates non-canonical innate immune signaling upon detection of the dsRNA-binding VSR of Drosophila C virus (DCV). VINR is required for the induction of antimicrobial peptide (AMP) genes but dispensable for antiviral RNAi. VINR functions by preventing the ubiquitin proteasome-dependent degradation of Cactin, a coiled-coil and arginine-serine-rich domain-containing protein that regulates a non-cannonical antimicrobial pathway for AMP induction. CRISPR-Cas9 knockout of VINR in Drosophila cells enhances DCV replication independently of antiviral RNAi, and VINR-knockout adult flies exhibit enhanced disease susceptibility to DCV and bacteria. Our findings reveal a counter counter-defense strategy activated by a lncRNA in response to the viral suppression of the primary antiviral RNAi immunity.
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Affiliation(s)
- Liqin Zhang
- Division of Molecular Medicine, Hefei National Laboratory for Physical Sciences at Microscale, CAS Key Laboratory of Innate Immunity and Chronic Disease, School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, China
| | - Wen Xu
- Division of Molecular Medicine, Hefei National Laboratory for Physical Sciences at Microscale, CAS Key Laboratory of Innate Immunity and Chronic Disease, School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, China
| | - Xinlei Gao
- Division of Molecular Medicine, Hefei National Laboratory for Physical Sciences at Microscale, CAS Key Laboratory of Innate Immunity and Chronic Disease, School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, China
| | - Wenjie Li
- Division of Molecular Medicine, Hefei National Laboratory for Physical Sciences at Microscale, CAS Key Laboratory of Innate Immunity and Chronic Disease, School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, China
| | - Shuishui Qi
- Division of Molecular Medicine, Hefei National Laboratory for Physical Sciences at Microscale, CAS Key Laboratory of Innate Immunity and Chronic Disease, School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, China
| | - Dongyang Guo
- Division of Molecular Medicine, Hefei National Laboratory for Physical Sciences at Microscale, CAS Key Laboratory of Innate Immunity and Chronic Disease, School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, China
| | - Olugbenga Emmanuel Ajayi
- Division of Molecular Medicine, Hefei National Laboratory for Physical Sciences at Microscale, CAS Key Laboratory of Innate Immunity and Chronic Disease, School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, China
| | - Shou-Wei Ding
- Department of Microbiology and Plant Pathology, Institute for Integrative Genome Biology, University of California, Riverside CA, USA
| | - Qingfa Wu
- Division of Molecular Medicine, Hefei National Laboratory for Physical Sciences at Microscale, CAS Key Laboratory of Innate Immunity and Chronic Disease, School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, China.
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7
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Swevers L, Liu J, Smagghe G. Defense Mechanisms against Viral Infection in Drosophila: RNAi and Non-RNAi. Viruses 2018; 10:E230. [PMID: 29723993 PMCID: PMC5977223 DOI: 10.3390/v10050230] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2018] [Revised: 04/20/2018] [Accepted: 04/27/2018] [Indexed: 12/20/2022] Open
Abstract
RNAi is considered a major antiviral defense mechanism in insects, but its relative importance as compared to other antiviral pathways has not been evaluated comprehensively. Here, it is attempted to give an overview of the antiviral defense mechanisms in Drosophila that involve both RNAi and non-RNAi. While RNAi is considered important in most viral infections, many other pathways can exist that confer antiviral resistance. It is noted that very few direct recognition mechanisms of virus infections have been identified in Drosophila and that the activation of immune pathways may be accomplished indirectly through cell damage incurred by viral replication. In several cases, protection against viral infection can be obtained in RNAi mutants by non-RNAi mechanisms, confirming the variability of the RNAi defense mechanism according to the type of infection and the physiological status of the host. This analysis is aimed at more systematically investigating the relative contribution of RNAi in the antiviral response and more specifically, to ask whether RNAi efficiency is affected when other defense mechanisms predominate. While Drosophila can function as a useful model, this issue may be more critical for economically important insects that are either controlled (agricultural pests and vectors of diseases) or protected from parasite infection (beneficial insects as bees) by RNAi products.
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Affiliation(s)
- Luc Swevers
- Institute of Biosciences & Applications, NCSR "Demokritos", 15341 Athens, Greece.
| | - Jisheng Liu
- School of Life Sciences, Guangzhou University, 510006 Guangzhou, China.
| | - Guy Smagghe
- Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, 9000 Ghent, Belgium.
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8
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Wong JT, Akhbar F, Ng AYE, Tay MLI, Loi GJE, Pek JW. DIP1 modulates stem cell homeostasis in Drosophila through regulation of sisR-1. Nat Commun 2017; 8:759. [PMID: 28970471 PMCID: PMC5624886 DOI: 10.1038/s41467-017-00684-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Accepted: 07/19/2017] [Indexed: 01/09/2023] Open
Abstract
Stable intronic sequence RNAs (sisRNAs) are by-products of splicing and regulate gene expression. How sisRNAs are regulated is unclear. Here we report that a double-stranded RNA binding protein, Disco-interacting protein 1 (DIP1) regulates sisRNAs in Drosophila. DIP1 negatively regulates the abundance of sisR-1 and INE-1 sisRNAs. Fine-tuning of sisR-1 by DIP1 is important to maintain female germline stem cell homeostasis by modulating germline stem cell differentiation and niche adhesion. Drosophila DIP1 localizes to a nuclear body (satellite body) and associates with the fourth chromosome, which contains a very high density of INE-1 transposable element sequences that are processed into sisRNAs. DIP1 presumably acts outside the satellite bodies to regulate sisR-1, which is not on the fourth chromosome. Thus, our study identifies DIP1 as a sisRNA regulatory protein that controls germline stem cell self-renewal in Drosophila. Stable intronic sequence RNAs (sisRNAs) are by-products of splicing from introns with roles in embryonic development in Drosophila. Here, the authors show that the RNA binding protein DIP1 regulates sisRNAs in Drosophila, which is necessary for germline stem cell homeostasis.
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Affiliation(s)
- Jing Ting Wong
- Ngee Ann Polytechnic, 535 Clementi Road, Singapore, 599489, Singapore
| | - Farzanah Akhbar
- Temasek Polytechnic, 21 Tampines Avenue 1, Singapore, 529757, Singapore
| | - Amanda Yunn Ee Ng
- Temasek Life Sciences Laboratory, 1 Research Link National University of Singapore, Singapore, 117604, Singapore
| | - Mandy Li-Ian Tay
- Temasek Life Sciences Laboratory, 1 Research Link National University of Singapore, Singapore, 117604, Singapore
| | - Gladys Jing En Loi
- National University of Singapore, 21 Lower Kent Ridge Road, Singapore, 119077, Singapore
| | - Jun Wei Pek
- Temasek Life Sciences Laboratory, 1 Research Link National University of Singapore, Singapore, 117604, Singapore.
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Keegan L, Khan A, Vukic D, O'Connell M. ADAR RNA editing below the backbone. RNA (NEW YORK, N.Y.) 2017; 23:1317-1328. [PMID: 28559490 PMCID: PMC5558901 DOI: 10.1261/rna.060921.117] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
ADAR RNA editing enzymes (adenosine deaminases acting on RNA) that convert adenosine bases to inosines were first identified biochemically 30 years ago. Since then, studies on ADARs in genetic model organisms, and evolutionary comparisons between them, continue to reveal a surprising range of pleiotropic biological effects of ADARs. This review focuses on Drosophila melanogaster, which has a single Adar gene encoding a homolog of vertebrate ADAR2 that site-specifically edits hundreds of transcripts to change individual codons in ion channel subunits and membrane and cytoskeletal proteins. Drosophila ADAR is involved in the control of neuronal excitability and neurodegeneration and, intriguingly, in the control of neuronal plasticity and sleep. Drosophila ADAR also interacts strongly with RNA interference, a key antiviral defense mechanism in invertebrates. Recent crystal structures of human ADAR2 deaminase domain-RNA complexes help to interpret available information on Drosophila ADAR isoforms and on the evolution of ADARs from tRNA deaminase ADAT proteins. ADAR RNA editing is a paradigm for the now rapidly expanding range of RNA modifications in mRNAs and ncRNAs. Even with recent progress, much remains to be understood about these groundbreaking ADAR RNA modification systems.
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Affiliation(s)
- Liam Keegan
- CEITEC at Masaryk University Brno, Pavilion A35, Brno CZ-62500, Czech Republic
| | - Anzer Khan
- CEITEC at Masaryk University Brno, Pavilion A35, Brno CZ-62500, Czech Republic
| | - Dragana Vukic
- CEITEC at Masaryk University Brno, Pavilion A35, Brno CZ-62500, Czech Republic
| | - Mary O'Connell
- CEITEC at Masaryk University Brno, Pavilion A35, Brno CZ-62500, Czech Republic
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piRNA pathway is not required for antiviral defense in Drosophila melanogaster. Proc Natl Acad Sci U S A 2016; 113:E4218-27. [PMID: 27357659 DOI: 10.1073/pnas.1607952113] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Since its discovery, RNA interference has been identified as involved in many different cellular processes, and as a natural antiviral response in plants, nematodes, and insects. In insects, the small interfering RNA (siRNA) pathway is the major antiviral response. In recent years, the Piwi-interacting RNA (piRNA) pathway also has been implicated in antiviral defense in mosquitoes infected with arboviruses. Using Drosophila melanogaster and an array of viruses that infect the fruit fly acutely or persistently or are vertically transmitted through the germ line, we investigated in detail the extent to which the piRNA pathway contributes to antiviral defense in adult flies. Following virus infection, the survival and viral titers of Piwi, Aubergine, Argonaute-3, and Zucchini mutant flies were similar to those of wild type flies. Using next-generation sequencing of small RNAs from wild type and siRNA mutant flies, we showed that no viral-derived piRNAs were produced in fruit flies during different types of viral infection. Our study provides the first evidence, to our knowledge, that the piRNA pathway does not play a major role in antiviral defense in adult Drosophila and demonstrates that viral-derived piRNA production depends on the biology of the host-virus combination rather than being part of a general antiviral process in insects.
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