1
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Le CT, Nguyen TD, Nguyen TA. Two-motif model illuminates DICER cleavage preferences. Nucleic Acids Res 2024; 52:1860-1877. [PMID: 38167721 PMCID: PMC10899750 DOI: 10.1093/nar/gkad1186] [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: 08/11/2023] [Revised: 11/25/2023] [Accepted: 12/02/2023] [Indexed: 01/05/2024] Open
Abstract
In humans, DICER is a key regulator of gene expression through its production of miRNAs and siRNAs by processing miRNA precursors (pre-miRNAs), short-hairpin RNAs (shRNAs), and long double-stranded RNAs (dsRNAs). To advance our understanding of this process, we employed high-throughput dicing assays using various shRNA variants and both wild-type and mutant DICER. Our analysis revealed that DICER predominantly cleaves shRNAs at two positions, specifically at 21 (DC21) and 22 (DC22) nucleotides from their 5'-end. Our investigation identified two different motifs, mWCU and YCR, that determine whether DICER cleaves at DC21 or DC22, depending on their locations in shRNAs/pre-miRNAs. These motifs can work together or independently to determine the cleavage sites of DICER. Furthermore, our findings indicate that dsRNA-binding domain (dsRBD) of DICER enhances its cleavage, and mWCU strengthens the interaction between dsRBD and RNA, leading to an even greater enhancement of the cleavage. Conversely, YCR functions independently of dsRBD. Our study proposes a two-motif model that sheds light on the intricate regulatory mechanisms involved in gene expression by elucidating how DICER recognizes its substrates, providing valuable insights into this critical biological process.
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Affiliation(s)
- Cong Truc Le
- Division of Life Science, The Hong Kong University of Science & Technology, Hong Kong, China
| | - Trung Duc Nguyen
- Division of Life Science, The Hong Kong University of Science & Technology, Hong Kong, China
| | - Tuan Anh Nguyen
- Division of Life Science, The Hong Kong University of Science & Technology, Hong Kong, China
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2
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Ortolá B, Daròs JA. RNA Interference in Insects: From a Natural Mechanism of Gene Expression Regulation to a Biotechnological Crop Protection Promise. BIOLOGY 2024; 13:137. [PMID: 38534407 DOI: 10.3390/biology13030137] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Revised: 02/14/2024] [Accepted: 02/19/2024] [Indexed: 03/28/2024]
Abstract
Insect pests rank among the major limiting factors in agricultural production worldwide. In addition to direct effect on crops, some phytophagous insects are efficient vectors for plant disease transmission. Large amounts of conventional insecticides are required to secure food production worldwide, with a high impact on the economy and environment, particularly when beneficial insects are also affected by chemicals that frequently lack the desired specificity. RNA interference (RNAi) is a natural mechanism gene expression regulation and protection against exogenous and endogenous genetic elements present in most eukaryotes, including insects. Molecules of double-stranded RNA (dsRNA) or highly structured RNA are the substrates of cellular enzymes to produce several types of small RNAs (sRNAs), which play a crucial role in targeting sequences for transcriptional or post-transcriptional gene silencing. The relatively simple rules that underlie RNAi regulation, mainly based in Watson-Crick complementarity, have facilitated biotechnological applications based on these cellular mechanisms. This includes the promise of using engineered dsRNA molecules, either endogenously produced in crop plants or exogenously synthesized and applied onto crops, as a new generation of highly specific, sustainable, and environmentally friendly insecticides. Fueled on this expectation, this article reviews current knowledge about the RNAi pathways in insects, and some other applied questions such as production and delivery of recombinant RNA, which are critical to establish RNAi as a reliable technology for insect control in crop plants.
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Affiliation(s)
- Beltrán Ortolá
- Instituto de Biología Molecular y Celular de Plantas, Consejo Superior de Investigaciones Científicas-Universitat Politècnica de València, 46022 Valencia, Spain
| | - José-Antonio Daròs
- Instituto de Biología Molecular y Celular de Plantas, Consejo Superior de Investigaciones Científicas-Universitat Politècnica de València, 46022 Valencia, Spain
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3
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Feng C, Torimaru K, Lim MYT, Chak LL, Shiimori M, Tsuji K, Tanaka T, Iida J, Okamura K. A novel eukaryotic RdRP-dependent small RNA pathway represses antiviral immunity by controlling an ERK pathway component in the black-legged tick. PLoS One 2023; 18:e0281195. [PMID: 36996253 PMCID: PMC10062562 DOI: 10.1371/journal.pone.0281195] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Accepted: 01/17/2023] [Indexed: 04/01/2023] Open
Abstract
Small regulatory RNAs (sRNAs) are involved in antiviral defense and gene regulation. Although roles of RNA-dependent RNA Polymerases (RdRPs) in sRNA biology are extensively studied in nematodes, plants and fungi, understanding of RdRP homologs in other animals is still lacking. Here, we study sRNAs in the ISE6 cell line, which is derived from the black-legged tick, an important vector of human and animal pathogens. We find abundant classes of ~22nt sRNAs that require specific combinations of RdRPs and sRNA effector proteins (Argonautes or AGOs). RdRP1-dependent sRNAs possess 5'-monophosphates and are mainly derived from RNA polymerase III-transcribed genes and repetitive elements. Knockdown of some RdRP homologs misregulates genes including RNAi-related genes and the regulator of immune response Dsor1. Sensor assays demonstrate that Dsor1 is downregulated by RdRP1 through the 3'UTR that contains a target site of RdRP1-dependent repeat-derived sRNAs. Consistent with viral gene repression by the RNAi mechanism using virus-derived small interfering RNAs, viral transcripts are upregulated by AGO knockdown. On the other hand, RdRP1 knockdown unexpectedly results in downregulation of viral transcripts. This effect is dependent on Dsor1, suggesting that antiviral immunity is enhanced by RdRP1 knockdown through Dsor1 upregulation. We propose that tick sRNA pathways control multiple aspects of immune response via RNAi and regulation of signaling pathways.
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Affiliation(s)
- Canran Feng
- Nara Institute of Science and Technology, Nara, Japan
| | | | - Mandy Yu Theng Lim
- Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, Singapore, Singapore
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Li-Ling Chak
- Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, Singapore, Singapore
| | | | - Kosuke Tsuji
- Nara Institute of Science and Technology, Nara, Japan
| | - Tetsuya Tanaka
- Joint Faculty of Veterinary Medicine, Laboratory of Infectious Diseases, Kagoshima University, Kagoshima, Japan
| | - Junko Iida
- Nara Institute of Science and Technology, Nara, Japan
| | - Katsutomo Okamura
- Nara Institute of Science and Technology, Nara, Japan
- Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, Singapore, Singapore
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
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4
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Jouravleva K, Golovenko D, Demo G, Dutcher RC, Hall TMT, Zamore PD, Korostelev AA. Structural basis of microRNA biogenesis by Dicer-1 and its partner protein Loqs-PB. Mol Cell 2022; 82:4049-4063.e6. [PMID: 36182693 PMCID: PMC9637774 DOI: 10.1016/j.molcel.2022.09.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Revised: 06/24/2022] [Accepted: 08/31/2022] [Indexed: 12/22/2022]
Abstract
In animals and plants, Dicer enzymes collaborate with double-stranded RNA-binding domain (dsRBD) proteins to convert precursor-microRNAs (pre-miRNAs) into miRNA duplexes. We report six cryo-EM structures of Drosophila Dicer-1 that show how Dicer-1 and its partner Loqs‑PB cooperate (1) before binding pre-miRNA, (2) after binding and in a catalytically competent state, (3) after nicking one arm of the pre-miRNA, and (4) following complete dicing and initial product release. Our reconstructions suggest that pre-miRNA binds a rare, open conformation of the Dicer‑1⋅Loqs‑PB heterodimer. The Dicer-1 dsRBD and three Loqs‑PB dsRBDs form a tight belt around the pre-miRNA, distorting the RNA helix to place the scissile phosphodiester bonds in the RNase III active sites. Pre-miRNA cleavage shifts the dsRBDs and partially closes Dicer-1, which may promote product release. Our data suggest a model for how the Dicer‑1⋅Loqs‑PB complex affects a complete cycle of pre-miRNA recognition, stepwise endonuclease cleavage, and product release.
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Affiliation(s)
- Karina Jouravleva
- RNA Therapeutics Institute, University of Massachusetts Chan Medical School, 368 Plantation Street, Worcester, MA 01605, USA
| | - Dmitrij Golovenko
- RNA Therapeutics Institute, University of Massachusetts Chan Medical School, 368 Plantation Street, Worcester, MA 01605, USA
| | - Gabriel Demo
- RNA Therapeutics Institute, University of Massachusetts Chan Medical School, 368 Plantation Street, Worcester, MA 01605, USA; Central European Institute of Technology, Masaryk University, Kamenice 5, Brno 62500, Czech Republic
| | - Robert C Dutcher
- Epigenetics and Stem Cell Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, 111 T.W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Traci M Tanaka Hall
- Epigenetics and Stem Cell Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, 111 T.W. Alexander Drive, Research Triangle Park, NC 27709, USA.
| | - Phillip D Zamore
- RNA Therapeutics Institute, University of Massachusetts Chan Medical School, 368 Plantation Street, Worcester, MA 01605, USA; Howard Hughes Medical Institute, University of Massachusetts Chan Medical School, 368 Plantation Street, Worcester, MA 01605, USA.
| | - Andrei A Korostelev
- RNA Therapeutics Institute, University of Massachusetts Chan Medical School, 368 Plantation Street, Worcester, MA 01605, USA.
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5
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Porrazzo A, Cipressa F, De Gregorio A, De Pittà C, Sales G, Ciapponi L, Morciano P, Esposito G, Tabocchini MA, Cenci G. Low dose rate γ-irradiation protects fruit fly chromosomes from double strand breaks and telomere fusions by reducing the esi-RNA biogenesis factor Loquacious. Commun Biol 2022; 5:905. [PMID: 36057690 PMCID: PMC9440893 DOI: 10.1038/s42003-022-03885-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Accepted: 08/23/2022] [Indexed: 12/03/2022] Open
Abstract
It is still continuously debated whether the low-dose/dose-rate (LDR) of ionizing radiation represents a hazard for humans. Model organisms, such as fruit flies, are considered valuable systems to reveal insights into this issue. We found that, in wild-type Drosophila melanogaster larval neuroblasts, the frequency of Chromosome Breaks (CBs), induced by acute γ-irradiation, is considerably reduced when flies are previously exposed to a protracted dose of 0.4 Gy delivered at a dose rate of 2.5 mGy/h. This indicates that this exposure, which is associated with an increased expression of DNA damage response proteins, induces a radioadaptive response (RAR) that protects Drosophila from extensive DNA damage. Interestingly, the same exposure reduces the frequency of telomere fusions (TFs) from Drosophila telomere capping mutants suggesting that the LDR can generally promote a protective response on chromatin sites that are recognized as DNA breaks. Deep RNA sequencing revealed that RAR is associated with a reduced expression of Loquacious D (Loqs-RD) gene that encodes a well-conserved dsRNA binding protein required for esiRNAs biogenesis. Remarkably, loss of Loqs mimics the LDR-mediated chromosome protection as it decreases the IR-induced CBs and TFs frequency. Thus, our molecular characterization of RAR identifies Loqs as a key factor in the cellular response to LDR and in the epigenetic routes involved in radioresistance. Chronic low y-radiation exposure to Drosophila cells decreases chromosome breaks induced by high-dose irradiation and telomere dysfunction by reducing the esiRNA biogenesis factor Loquacious D.
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Affiliation(s)
- A Porrazzo
- Dipartimento di Biologia e Biotecnologie "C. Darwin", Sapienza Università di Roma, Rome, Italy.,Fondazione Cenci Bolognetti/ Istituto Pasteur Italia, Rome, Italy
| | - F Cipressa
- Fondazione Cenci Bolognetti/ Istituto Pasteur Italia, Rome, Italy.,Centro Studi e Ricerche "Enrico Fermi", Rome, Italy
| | - A De Gregorio
- Dipartimento di Biologia e Biotecnologie "C. Darwin", Sapienza Università di Roma, Rome, Italy
| | - C De Pittà
- Dipartimento di Biologia, Università di Padova, Padua, Italy
| | - G Sales
- Dipartimento di Biologia, Università di Padova, Padua, Italy
| | - L Ciapponi
- Dipartimento di Biologia e Biotecnologie "C. Darwin", Sapienza Università di Roma, Rome, Italy
| | - P Morciano
- INFN-Laboratori Nazionali del Gran Sasso, 67100, Assergi, Italy
| | - G Esposito
- Istituto Superiore di Sanita' ISS, Rome, Italy.,INFN-Roma 1, Rome, Italy
| | | | - G Cenci
- Dipartimento di Biologia e Biotecnologie "C. Darwin", Sapienza Università di Roma, Rome, Italy. .,Fondazione Cenci Bolognetti/ Istituto Pasteur Italia, Rome, Italy.
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6
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Pandey M, Luhur A, Sokol NS, Chawla G. Molecular Dissection of a Conserved Cluster of miRNAs Identifies Critical Structural Determinants That Mediate Differential Processing. Front Cell Dev Biol 2022; 10:909212. [PMID: 35784477 PMCID: PMC9247461 DOI: 10.3389/fcell.2022.909212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Accepted: 05/25/2022] [Indexed: 11/13/2022] Open
Abstract
Differential processing is a hallmark of clustered microRNAs (miRNAs) and the role of position and order of miRNAs in a cluster together with the contribution of stem-base and terminal loops has not been explored extensively within the context of a polycistronic transcript. To elucidate the structural attributes of a polycistronic transcript that contribute towards the differences in efficiencies of processing of the co-transcribed miRNAs, we constructed a series of chimeric variants of Drosophila let-7-Complex that encodes three evolutionary conserved and differentially expressed miRNAs (miR-100, let-7 and miR-125) and examined the expression and biological activity of the encoded miRNAs. The kinetic effects of Drosha and Dicer processing on the chimeric precursors were examined by in vitro processing assays. Our results highlight the importance of stem-base and terminal loop sequences in differential expression of polycistronic miRNAs and provide evidence that processing of a particular miRNA in a polycistronic transcript is in part determined by the kinetics of processing of adjacent miRNAs in the same cluster. Overall, this analysis provides specific guidelines for achieving differential expression of a particular miRNA in a cluster by structurally induced changes in primary miRNA (pri-miRNA) sequences.
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Affiliation(s)
- Manish Pandey
- RNA Biology Laboratory, Regional Centre for Biotechnology, Faridabad, India
| | - Arthur Luhur
- Department of Biology, Indiana University, Bloomington, IN, United States
| | - Nicholas S. Sokol
- Department of Biology, Indiana University, Bloomington, IN, United States
| | - Geetanjali Chawla
- RNA Biology Laboratory, Regional Centre for Biotechnology, Faridabad, India
- *Correspondence: Geetanjali Chawla,
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7
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Zhu L, Kandasamy SK, Fukunaga R. Dicer partner protein tunes the length of miRNAs using base-mismatch in the pre-miRNA stem. Nucleic Acids Res 2019; 46:3726-3741. [PMID: 29373753 PMCID: PMC5909426 DOI: 10.1093/nar/gky043] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Accepted: 01/17/2018] [Indexed: 12/19/2022] Open
Abstract
Dicer partner proteins Drosophila Loquacious-PB (Loqs-PB) and human TRBP tune the length of miRNAs produced by Dicer from a subset of pre-miRNAs and thereby alter their target repertoire, by an unknown mechanism. Here, we developed a novel high-throughput method that we named Dram-seq (Dice randomized pre-miRNA pool and seq) to study length distributions of miRNAs produced from thousands of different pre-miRNA variants. Using Dram-seq, we found that a base-mismatch in the pre-miRNA stem can alter the length of miRNAs compared with a base-pair at the same position in both Drosophila and human, and is important for the miRNA length tuning by Loqs-PB. Loqs-PB directly bound base-mismatched nucleotides in the pre-miRNA stem. We speculate that Loqs-PB tunes miRNA length by changing the conformation of base-mismatched nucleotides in the pre-miRNA stem to that of base-paired ones and thereby altering the distance of the pre-miRNA stem.
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Affiliation(s)
- Li Zhu
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, 725 North Wolfe Street, 521A Physiology Building, Baltimore, MD 21205, USA
| | - Suresh K Kandasamy
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, 725 North Wolfe Street, 521A Physiology Building, Baltimore, MD 21205, USA
| | - Ryuya Fukunaga
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, 725 North Wolfe Street, 521A Physiology Building, Baltimore, MD 21205, USA
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8
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Xie B, Morton DB, Cook TA. Opposing transcriptional and post-transcriptional roles for Scalloped in binary Hippo-dependent neural fate decisions. Dev Biol 2019; 455:51-59. [PMID: 31265830 DOI: 10.1016/j.ydbio.2019.06.022] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Revised: 06/28/2019] [Accepted: 06/28/2019] [Indexed: 01/07/2023]
Abstract
The Hippo tumor suppressor pathway plays many fundamental cell biological roles during animal development. Two central players in controlling Hippo-dependent gene expression are the TEAD transcription factor Scalloped (Sd) and its transcriptional co-activator Yorkie (Yki). Hippo signaling phosphorylates Yki, thereby blocking Yki-dependent transcriptional control. In post-mitotic Drosophila photoreceptors, a bistable negative feedback loop forms between the Hippo-dependent kinase Warts/Lats and Yki to lock in green vs blue-sensitive neuronal subtype choices, respectively. Previous experiments indicate that sd and yki mutants phenocopy each other's functions, both being required for promoting the expression of the blue photoreceptor fate determinant melted (melt) and the blue-sensitive opsin Rh5. Here, we demonstrate that Sd ensures the robustness of this neuronal fate decision via multiple antagonistic gene regulatory roles. In Hippo-positive (green) photoreceptors, Sd directly represses both melt and Rh5 gene expression through defined TEAD binding sites, a mechanism that is antagonized by Yki in Hippo-negative (blue) cells. Additionally, in blue photoreceptors, Sd is required to promote the translation of the Rh5 protein through a 3'UTR-dependent and microRNA-mediated process. Together, these studies reveal that Sd can drive context-dependent cell fate decisions through opposing transcriptional and post-transcriptional mechanisms.
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Affiliation(s)
- Baotong Xie
- Department of Integrative Biosciences, Oregon Health & Science University, Portland, OR, 97239, USA.
| | - David B Morton
- Department of Integrative Biosciences, Oregon Health & Science University, Portland, OR, 97239, USA
| | - Tiffany A Cook
- Center of Molecular Medicine and Genetics and Department of Ophthalmology, Visual and Anatomical Sciences, Wayne State University School of Medicine, Detroit, MI, 48201, USA.
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9
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Luhur A, Klueg KM, Zelhof AC. Generating and working with Drosophila cell cultures: Current challenges and opportunities. WILEY INTERDISCIPLINARY REVIEWS-DEVELOPMENTAL BIOLOGY 2018; 8:e339. [PMID: 30561900 DOI: 10.1002/wdev.339] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Revised: 10/30/2018] [Accepted: 11/21/2018] [Indexed: 12/26/2022]
Abstract
The use of Drosophila cell cultures has positively impacted both fundamental and biomedical research. The most widely used cell lines: Schneider, Kc, the CNS and imaginal disc lines continue to be the choice for many applications. Drosophila cell lines provide a homogenous source of cells suitable for biochemical experimentations, transcriptomics, functional genomics, and biomedical applications. They are amenable to RNA interference and serve as a platform for high-throughput screens to identify relevant candidate genes or drugs for any biological process. Currently, CRISPR-based functional genomics are also being developed for Drosophila cell lines. Even though many uniquely derived cell lines exist, cell genetic techniques such the transgenic UAS-GAL4-based RasV12 oncogene expression, CRISPR-Cas9 editing and recombination mediated cassette exchange are likely to drive the establishment of many more lines from specific tissues, cells, or genotypes. However, the pace of creating new lines is hindered by several factors inherent to working with Drosophila cell cultures: single cell cloning, optimal media formulations and culture conditions capable of supporting lines from novel tissue sources or genotypes. Moreover, even though many Drosophila cell lines are morphologically and transcriptionally distinct it may be necessary to implement a standard for Drosophila cell line authentication, ensuring the identity and purity of each cell line. Altogether, recent advances and a standardized authentication effort should improve the utility of Drosophila cell cultures as a relevant model for fundamental and biomedical research. This article is categorized under: Technologies > Analysis of Cell, Tissue, and Animal Phenotypes.
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Affiliation(s)
- Arthur Luhur
- Department of Biology, Drosophila Genomics Resource Center, Indiana University Bloomington, Bloomington, Indiana
| | - Kristin M Klueg
- Department of Biology, Drosophila Genomics Resource Center, Indiana University Bloomington, Bloomington, Indiana
| | - Andrew C Zelhof
- Department of Biology, Drosophila Genomics Resource Center, Indiana University Bloomington, Bloomington, Indiana
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10
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Zhou L, Lim MYT, Kaur P, Saj A, Bortolamiol-Becet D, Gopal V, Tolwinski N, Tucker-Kellogg G, Okamura K. Importance of miRNA stability and alternative primary miRNA isoforms in gene regulation during Drosophila development. eLife 2018; 7:e38389. [PMID: 30024380 PMCID: PMC6066331 DOI: 10.7554/elife.38389] [Citation(s) in RCA: 26] [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: 05/16/2018] [Accepted: 07/04/2018] [Indexed: 12/19/2022] Open
Abstract
Mature microRNAs (miRNAs) are processed from primary transcripts (pri-miRNAs), and their expression is controlled at transcriptional and post-transcriptional levels. However, how regulation at multiple levels achieves precise control remains elusive. Using published and new datasets, we profile a time course of mature and pri-miRNAs in Drosophila embryos and reveal the dynamics of miRNA production and degradation as well as dynamic changes in pri-miRNA isoform selection. We found that 5' nucleotides influence stability of mature miRNAs. Furthermore, distinct half-lives of miRNAs from the mir-309 cluster shape their temporal expression patterns, and the importance of rapid degradation of the miRNAs in gene regulation is detected as distinct evolutionary signatures at the target sites in the transcriptome. Finally, we show that rapid degradation of miR-3/-309 may be important for regulation of the planar cell polarity pathway component Vang. Altogether, the results suggest that complex mechanisms regulate miRNA expression to support normal development.
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Affiliation(s)
- Li Zhou
- Temasek Life Sciences LaboratorySingaporeSingapore
- Department of Biological Sciences, Faculty of ScienceNational University of SingaporeSingaporeSingapore
| | - Mandy Yu Theng Lim
- Temasek Life Sciences LaboratorySingaporeSingapore
- School of Biological SciencesNanyang Technological UniversitySingaporeSingapore
| | - Prameet Kaur
- Division of ScienceYale-NUS CollegeSingaporeSingapore
| | - Abil Saj
- Cancer Therapeutics and Stratified OncologyGenome Institute of SingaporeSingaporeSingapore
| | | | - Vikneswaran Gopal
- Department of Statistics and Applied Probability, Faculty of ScienceNational University of SingaporeSingaporeSingapore
| | - Nicholas Tolwinski
- Department of Biological Sciences, Faculty of ScienceNational University of SingaporeSingaporeSingapore
- Division of ScienceYale-NUS CollegeSingaporeSingapore
| | - Greg Tucker-Kellogg
- Department of Biological Sciences, Faculty of ScienceNational University of SingaporeSingaporeSingapore
| | - Katsutomo Okamura
- Temasek Life Sciences LaboratorySingaporeSingapore
- School of Biological SciencesNanyang Technological UniversitySingaporeSingapore
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11
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Davis-Vogel C, Ortiz A, Procyk L, Robeson J, Kassa A, Wang Y, Huang E, Walker C, Sethi A, Nelson ME, Sashital DG. Knockdown of RNA interference pathway genes impacts the fitness of western corn rootworm. Sci Rep 2018; 8:7858. [PMID: 29777111 PMCID: PMC5959937 DOI: 10.1038/s41598-018-26129-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Accepted: 05/04/2018] [Indexed: 12/11/2022] Open
Abstract
Western corn rootworm (Diabrotica virgifera virgifera) is a serious agricultural pest known for its high adaptability to various management strategies, giving rise to a continual need for new control options. Transgenic maize expressing insecticidal RNAs represents a novel mode of action for rootworm management that is dependent on the RNA interference (RNAi) pathways of the insect for efficacy. Preliminary evidence suggests that western corn rootworm could develop broad resistance to all insecticidal RNAs through changes in RNAi pathway genes; however, the likelihood of field-evolved resistance occurring through this mechanism remains unclear. In the current study, eight key genes involved in facilitating interference in the microRNA and small interfering RNA pathways were targeted for knockdown in order to evaluate impact on fitness of western corn rootworm. These genes include drosha, dicer-1, dicer-2, pasha, loquacious, r2d2, argonaute 1, and argonaute 2. Depletion of targeted transcripts in rootworm larvae led to changes in microRNA expression, decreased ability to pupate, reduced adult beetle emergence, and diminished reproductive capacity. The observed effects do not support evolution of resistance through changes in expression of these eight genes due to reduced insect fitness.
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Affiliation(s)
- Courtney Davis-Vogel
- Research and Development, DuPont Pioneer, 7300 NW 62nd Ave., Johnston, IA, USA.
- Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, 2437 Pammel Dr., Ames, IA, USA.
| | - Angel Ortiz
- Research and Development, DuPont Pioneer, 7300 NW 62nd Ave., Johnston, IA, USA
| | - Lisa Procyk
- Research and Development, DuPont Pioneer, 7300 NW 62nd Ave., Johnston, IA, USA
| | - Jonathan Robeson
- Research and Development, DuPont Pioneer, 7300 NW 62nd Ave., Johnston, IA, USA
| | - Adane Kassa
- Research and Development, DuPont Pioneer, 7300 NW 62nd Ave., Johnston, IA, USA
| | - Yiwei Wang
- Research and Development, DuPont Pioneer, 7300 NW 62nd Ave., Johnston, IA, USA
| | - Emily Huang
- Research and Development, DuPont Pioneer, 7300 NW 62nd Ave., Johnston, IA, USA
| | - Carl Walker
- Research and Development, DuPont Pioneer, 7300 NW 62nd Ave., Johnston, IA, USA
| | - Amit Sethi
- Research and Development, DuPont Pioneer, 7300 NW 62nd Ave., Johnston, IA, USA
| | - Mark E Nelson
- Research and Development, DuPont Pioneer, 7300 NW 62nd Ave., Johnston, IA, USA
| | - Dipali G Sashital
- Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, 2437 Pammel Dr., Ames, IA, USA
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12
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Loquacious-PD facilitates Drosophila Dicer-2 cleavage through interactions with the helicase domain and dsRNA. Proc Natl Acad Sci U S A 2017; 114:E7939-E7948. [PMID: 28874570 DOI: 10.1073/pnas.1707063114] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Loquacious-PD (Loqs-PD) is required for biogenesis of many endogenous siRNAs in Drosophila In vitro, Loqs-PD enhances the rate of dsRNA cleavage by Dicer-2 and also enables processing of substrates normally refractory to cleavage. Using purified components, and Loqs-PD truncations, we provide a mechanistic basis for Loqs-PD functions. Our studies indicate that the 22 amino acids at the C terminus of Loqs-PD, including an FDF-like motif, directly interact with the Hel2 subdomain of Dicer-2's helicase domain. This interaction is RNA-independent, but we find that modulation of Dicer-2 cleavage also requires dsRNA binding by Loqs-PD. Furthermore, while the first dsRNA-binding motif of Loqs-PD is dispensable for enhancing cleavage of optimal substrates, it is essential for enhancing cleavage of suboptimal substrates. Finally, our studies define a previously unrecognized Dicer interaction interface and suggest that Loqs-PD is well positioned to recruit substrates into the helicase domain of Dicer-2.
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Lim MYT, Okamura K. Switches in Dicer Activity During Oogenesis and Early Development. Results Probl Cell Differ 2017; 63:325-351. [PMID: 28779324 DOI: 10.1007/978-3-319-60855-6_14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Dicer is a versatile protein regulating diverse biological processes via the production of multiple classes of small regulatory RNAs, including microRNAs (miRNAs) and small interfering RNAs (siRNAs). In this chapter, we will discuss roles for Dicer in driving temporal changes in activity of individual small RNA classes to support oogenesis and early embryogenesis. Genetic strategies that perturb particular functions of Dicer family proteins, such as ablation of individual Dicer paralogs or their binding partners as well as introduction of point mutations to individual domains, allowed the dissection of Dicer functions in diverse small RNA pathways. Evolutionary conservation and divergence of the mechanisms highlight the importance of Dicer versatility in supporting rapid changes in gene expression during oogenesis and early development. Furthermore, we will discuss potential roles of Dicer in transgenerational inheritance of small RNA-mediated gene regulation.
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Affiliation(s)
- Mandy Yu Theng Lim
- Temasek Life Sciences Laboratory, National University of Singapore, 1 Research Link, Singapore, 117604, Singapore
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore, 639798, Singapore
| | - Katsutomo Okamura
- Temasek Life Sciences Laboratory, National University of Singapore, 1 Research Link, Singapore, 117604, Singapore.
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore, 639798, Singapore.
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