1
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Parvez F, Sangpal D, Paithankar H, Amin Z, Chugh J. Differential conformational dynamics in two type-A RNA-binding domains drive the double-stranded RNA recognition and binding. eLife 2024; 13:RP94842. [PMID: 39116184 PMCID: PMC11309768 DOI: 10.7554/elife.94842] [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] [Indexed: 08/10/2024] Open
Abstract
Trans-activation response (TAR) RNA-binding protein (TRBP) has emerged as a key player in the RNA interference pathway, wherein it binds to different pre-microRNAs (miRNAs) and small interfering RNAs (siRNAs), each varying in sequence and/or structure. We hypothesize that TRBP displays dynamic adaptability to accommodate heterogeneity in target RNA structures. Thus, it is crucial to ascertain the role of intrinsic and RNA-induced protein dynamics in RNA recognition and binding. We have previously elucidated the role of intrinsic and RNA-induced conformational exchange in the double-stranded RNA-binding domain 1 (dsRBD1) of TRBP in shape-dependent RNA recognition. The current study delves into the intrinsic and RNA-induced conformational dynamics of the TRBP-dsRBD2 and then compares it with the dsRBD1 study carried out previously. Remarkably, the two domains exhibit differential binding affinity to a 12-bp dsRNA owing to the presence of critical residues and structural plasticity. Furthermore, we report that dsRBD2 depicts constrained conformational plasticity when compared to dsRBD1. Although, in the presence of RNA, dsRBD2 undergoes induced conformational exchange within the designated RNA-binding regions and other residues, the amplitude of the motions remains modest when compared to those observed in dsRBD1. We propose a dynamics-driven model of the two tandem domains of TRBP, substantiating their contributions to the versatility of dsRNA recognition and binding.
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Affiliation(s)
- Firdousi Parvez
- Department of Biology, Indian Institute of Science Education and Research (IISER)PuneIndia
| | - Devika Sangpal
- Department of Biotechnology (with jointly merged Institute of Bioinformatics and Biotechnology), Savitribai Phule Pune UniversityPuneIndia
| | - Harshad Paithankar
- Department of Chemistry, Indian Institute of Science Education and Research (IISER)PuneIndia
| | - Zainab Amin
- Department of Chemistry, Indian Institute of Science Education and Research (IISER)PuneIndia
| | - Jeetender Chugh
- Department of Chemistry, Indian Institute of Science Education and Research (IISER)PuneIndia
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2
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Aute R, Waghela N, Deshmukh MV. Key arginine residues in R2D2 dsRBD1 and dsRBD2 lead the siRNA recognition in Drosophila melanogaster RNAi pathway. Biophys Chem 2024; 310:107247. [PMID: 38663122 DOI: 10.1016/j.bpc.2024.107247] [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: 01/17/2024] [Revised: 04/04/2024] [Accepted: 04/16/2024] [Indexed: 05/23/2024]
Abstract
In Drosophila melanogaster, Dcr-2:R2D2 heterodimer binds to the 21 nucleotide siRNA duplex to form the R2D2/Dcr-2 Initiator (RDI) complex, which is critical for the initiation of siRNA-induced silencing complex (RISC) assembly. During RDI complex formation, R2D2, a protein that contains three dsRNA binding domains (dsRBD), senses two aspects of the siRNA: thermodynamically more stable end (asymmetry sensing) and the 5'-phosphate (5'-P) recognition. Despite several detailed studies to date, the molecular determinants arising from R2D2 for performing these two tasks remain elusive. In this study, we have performed structural, biophysical, and biochemical characterization of R2D2 dsRBDs. We found that the solution NMR-derived structure of R2D2 dsRBD1 yielded a canonical α1-β1-β2-β3-α2 fold, wherein two arginine salt bridges provide additional stability to the R2D2 dsRBD1. Furthermore, we show that R2D2 dsRBD1 interacts with thermodynamically asymmetric siRNA duplex independent of its 5'-phosphorylation state, whereas R2D2 dsRBD2 prefers to interact with 5'-P siRNA duplex. The mutation of key arginine residues, R53 and R101, in concatenated dsRBDs of R2D2 results in a significant loss of siRNA duplex recognition. Our study deciphers the active roles of R2D2 dsRBDs by showing that dsRBD1 initiates siRNA recognition, whereas dsRBD2 senses 5'-phosphate as an authentic mark on functional siRNA.
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Affiliation(s)
- Ramdas Aute
- CSIR - Centre for Cellular and Molecular Biology, Council of Scientific and Industrial Research, Uppal Road, Hyderabad 500007, Telangana, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Nilam Waghela
- CSIR - Centre for Cellular and Molecular Biology, Council of Scientific and Industrial Research, Uppal Road, Hyderabad 500007, Telangana, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Mandar V Deshmukh
- CSIR - Centre for Cellular and Molecular Biology, Council of Scientific and Industrial Research, Uppal Road, Hyderabad 500007, Telangana, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India.
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3
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Paul J, Deshmukh MV. Chemical shift assignment of dsRBD1 and dsRBD2 of Arabidopsis thaliana DRB3, an essential protein involved in RNAi-mediated antiviral defense. BIOMOLECULAR NMR ASSIGNMENTS 2024; 18:99-104. [PMID: 38668800 DOI: 10.1007/s12104-024-10174-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2024] [Accepted: 04/14/2024] [Indexed: 05/12/2024]
Abstract
As sessile organisms, plants need to counteract different biotic and abiotic stresses to survive. RNA interference provides natural immunity against various plant pathogens, especially against viral infections via inhibition of viral genome replication or translation. In plants, DRB3, a multi-domain protein containing two N-terminal dsRNA binding domains (dsRBD), plays a vital role in RNA-directed DNA methylation of the geminiviral genome. Additionally, DRB3 arrests the replication of the viral genome in the viral replication complex of RNA viruses through a mechanism that has yet to be fully deciphered. Therefore, as a first step towards exploring the structural details of DRB3, we present a nearly complete backbone and side chain assignment of the two N-terminal dsRBD domains.
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Affiliation(s)
- Jaydeep Paul
- CSIR - Centre for Cellular and Molecular Biology, Council of Scientific and Industrial Research, Uppal Road, Hyderabad, Telangana, 500007, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
| | - Mandar V Deshmukh
- CSIR - Centre for Cellular and Molecular Biology, Council of Scientific and Industrial Research, Uppal Road, Hyderabad, Telangana, 500007, India.
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India.
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4
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Aute R, Deshmukh MV. Chemical shift assignments of dsRBD1 and linker region of R2D2, a siRNA binding protein in the Drosophila RNAi pathway. BIOMOLECULAR NMR ASSIGNMENTS 2023; 17:211-215. [PMID: 37405581 DOI: 10.1007/s12104-023-10143-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2023] [Accepted: 06/23/2023] [Indexed: 07/06/2023]
Abstract
In the model organism Drosophila melanogaster, one of the Dicer homologs, Dcr-2, initiates the RNA interference pathway by cleaving long double-stranded RNA into small interfering RNA (siRNA). The Dcr-2:R2D2 heterodimer subsequently binds to the 21-nucleotide siRNA to form the R2D2:Dcr-2 Initiator (RDI) complex, which is critical for initiating the assembly of the RNA-induced silencing complex containing guide siRNA strand. During RDI complex formation, R2D2 senses the stability of the 5' end of the siRNA and a 5'-phosphate group, although the underlying mechanism of siRNA asymmetry sensing and 5'-phosphate recognition by R2D2 is elusive. In this study, we present nearly complete chemical shift assignments of the backbone and the side chain of a construct that comprises the N-terminus dsRBD1 and linker of R2D2 (~ 10.3 kDa; henceforth: R2D2D1L). Our study would further aid in the structural and functional characterization of R2D2.
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Affiliation(s)
- Ramdas Aute
- CSIR-Centre for Cellular and Molecular Biology, Council of Scientific and Industrial Research, Uppal Road, Hyderabad, Telangana, 500007, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
| | - Mandar V Deshmukh
- CSIR-Centre for Cellular and Molecular Biology, Council of Scientific and Industrial Research, Uppal Road, Hyderabad, Telangana, 500007, India.
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India.
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5
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Paturi S, Deshmukh MV. NMR resonance assignments of 18.5 kDa complex of Arabidopsis thaliana DRB7.2:DRB4 interaction domains. BIOMOLECULAR NMR ASSIGNMENTS 2023; 17:173-178. [PMID: 37256435 DOI: 10.1007/s12104-023-10137-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Accepted: 05/24/2023] [Indexed: 06/01/2023]
Abstract
In higher eukaryotes, the dsRNA binding proteins (dsRBPs) assist the corresponding Dicer in the cleavage of dsRNA precursors to effect post-transcriptional gene regulation through RNA interference. In contrast, the DRB7.2:DRB4 complex in Arabidopsis thaliana acts as a potent inhibitor of Dicer-like 3 (DCL3) processing by sequestering endogenous inverted-repeat dsRNA precursors. DRB7.2 possesses a single dsRNA Binding Domain (dsRBD) flanked by unstructured N- and C-terminal regions. Whereas, DRB4 has two concatenated N-terminal dsRBDs and a long unstructured C-terminus harboring a small domain of unidentified function, D3. Here, we present near-complete backbone and partial side chain assignments of the interaction domains, DRB7.2M (i.e., DRB7.2 (71-162)) and DRB4D3 (i.e., DRB4 (294-355)) as a complex. Our findings establish the groundwork for future structural, dynamic, and functional research on DRB7.2 and DRB4, and provide clues for the endo-IR pathway in plants.
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Affiliation(s)
- Sneha Paturi
- CSIR - Centre for Cellular and Molecular Biology, Council of Scientific and Industrial Research, Uppal Road, Hyderabad, 500007, Telangana, India
| | - Mandar V Deshmukh
- CSIR - Centre for Cellular and Molecular Biology, Council of Scientific and Industrial Research, Uppal Road, Hyderabad, 500007, Telangana, India.
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6
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Paithankar H, Tarang GS, Parvez F, Marathe A, Joshi M, Chugh J. Inherent conformational plasticity in dsRBDs enables interaction with topologically distinct RNAs. Biophys J 2022; 121:1038-1055. [PMID: 35134335 PMCID: PMC8943759 DOI: 10.1016/j.bpj.2022.02.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2021] [Revised: 12/25/2021] [Accepted: 02/03/2022] [Indexed: 11/02/2022] Open
Abstract
Many double-stranded RNA-binding domains (dsRBDs) interact with topologically distinct dsRNAs in biological pathways pivotal to viral replication, cancer causation, neurodegeneration, and so on. We hypothesized that the adaptability of dsRBDs is essential to target different dsRNA substrates. A model dsRBD and a few dsRNAs, slightly different in shape from each other, were used to test the systematic shape dependence of RNA on the dsRBD-binding using nuclear magnetic resonance (NMR) spectroscopy and molecular modeling. NMR-based titrations showed a distinct binding pattern for the dsRBD with the topologically distinct dsRNAs. The line broadening upon RNA binding was observed to cluster in the residues lying in close proximity, thereby suggesting an RNA-induced conformational exchange in the dsRBD. Further, while the intrinsic microsecond dynamics observed in the apo-dsRBD were found to quench upon binding with the dsRNA, the microsecond dynamics got induced at residues spatially proximal to quench sites upon binding with the dsRNA. This apparent relay of conformational exchange suggests the significance of intrinsic dynamics to help adapt the dsRBD to target various dsRNA-shapes. The conformational pool visualized in MD simulations for the apo-dsRBD reported here has also been observed to sample the conformations seen previously for various dsRBDs in apo- and in dsRNA-bound state structures, further suggesting the conformational adaptability of the dsRBDs. These investigations provide a dynamic basis for the substrate promiscuity for dsRBD proteins.
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Affiliation(s)
- Harshad Paithankar
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Pune, Maharashtra, India
| | - Guneet Singh Tarang
- Department of Biology, Indian Institute of Science Education and Research (IISER), Pune, Maharashtra, India
| | - Firdousi Parvez
- Department of Biology, Indian Institute of Science Education and Research (IISER), Pune, Maharashtra, India
| | - Aniket Marathe
- Bioinformatics Center, Savitrabai Phule Pune University, Pune, Maharashtra, India
| | - Manali Joshi
- Bioinformatics Center, Savitrabai Phule Pune University, Pune, Maharashtra, India
| | - Jeetender Chugh
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Pune, Maharashtra, India; Department of Biology, Indian Institute of Science Education and Research (IISER), Pune, Maharashtra, India.
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7
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Lewandowska D, Orr J, Schreiber M, Colas I, Ramsay L, Zhang R, Waugh R. The proteome of developing barley anthers during meiotic prophase I. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:1464-1482. [PMID: 34758083 PMCID: PMC8890616 DOI: 10.1093/jxb/erab494] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Accepted: 11/08/2021] [Indexed: 05/11/2023]
Abstract
Flowering plants reproduce sexually by combining a haploid male and female gametophyte during fertilization. Male gametophytes are localized in the anthers, each containing reproductive (meiocyte) and non-reproductive tissue necessary for anther development and maturation. Meiosis, where chromosomes pair and exchange their genetic material during a process called recombination, is one of the most important and sensitive stages in breeding, ensuring genetic diversity. Most anther development studies have focused on transcript variation, but very few have been correlated with protein abundance. Taking advantage of a recently published barley anther transcriptomic (BAnTr) dataset and a newly developed sensitive mass spectrometry-based approach to analyse the barley anther proteome, we conducted high-resolution mass spectrometry analysis of barley anthers, collected at six time points and representing their development from pre-meiosis to metaphase. Each time point was carefully staged using immunocytology, providing a robust and accurate staging mirroring our previous BAnTr dataset. We identified >6100 non-redundant proteins including 82 known and putative meiotic proteins. Although the protein abundance was relatively stable throughout prophase I, we were able to quantify the dynamic variation of 336 proteins. We present the first quantitative comparative proteomics study of barley anther development during meiotic prophase I when the important process of homologous recombination is taking place.
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Affiliation(s)
- Dominika Lewandowska
- Cell and Molecular Sciences, The James Hutton Institute, Invergowrie, Dundee DD2 5DA, UK
| | - Jamie Orr
- Cell and Molecular Sciences, The James Hutton Institute, Invergowrie, Dundee DD2 5DA, UK
| | - Miriam Schreiber
- Cell and Molecular Sciences, The James Hutton Institute, Invergowrie, Dundee DD2 5DA, UK
| | - Isabelle Colas
- Cell and Molecular Sciences, The James Hutton Institute, Invergowrie, Dundee DD2 5DA, UK
| | - Luke Ramsay
- Cell and Molecular Sciences, The James Hutton Institute, Invergowrie, Dundee DD2 5DA, UK
| | - Runxuan Zhang
- Information and Computational Sciences, The James Hutton Institute, Invergowrie, Dundee DD2 5DA, UK
| | - Robbie Waugh
- Cell and Molecular Sciences, The James Hutton Institute, Invergowrie, Dundee DD2 5DA, UK
- Division of Plant Sciences, University of Dundee, The James Hutton Institute, Invergowrie, Dundee DD2 5DA, UK
- School of Agriculture, Food and Wine, Waite Research Institute, University of Adelaide, Waite Research Precinct, Glen Osmond, SA 5064, Australia
- Correspondence:
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8
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Fátyol K, Fekete KA, Ludman M. Double-Stranded-RNA-Binding Protein 2 Participates in Antiviral Defense. J Virol 2020; 94:e00017-20. [PMID: 32213615 PMCID: PMC7269452 DOI: 10.1128/jvi.00017-20] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2020] [Accepted: 03/17/2020] [Indexed: 01/01/2023] Open
Abstract
Double-stranded RNA (dsRNA) is a common pattern formed during the replication of both RNA and DNA viruses. Perception of virus-derived dsRNAs by specialized receptor molecules leads to the activation of various antiviral measures. In plants, these defensive processes include the adaptive RNA interference (RNAi) pathway and innate pattern-triggered immune (PTI) responses. While details of the former process have been well established in recent years, the latter are still only partially understood at the molecular level. Nonetheless, emerging data suggest extensive cross talk between the different antiviral mechanisms. Here, we demonstrate that dsRNA-binding protein 2 (DRB2) of Nicotiana benthamiana plays a direct role in potato virus X (PVX)-elicited systemic necrosis. These results establish that DRB2, a known component of RNAi, is also involved in a virus-induced PTI response. In addition, our findings suggest that RNA-dependent polymerase 6 (RDR6)-dependent dsRNAs play an important role in the triggering of PVX-induced systemic necrosis. Based on our data, a model is formulated whereby competition between different DRB proteins for virus-derived dsRNAs helps establish the dominant antiviral pathways that are activated in response to virus infection.IMPORTANCE Plants employ multiple defense mechanisms to restrict viral infections, among which RNA interference is the best understood. The activation of innate immunity often leads to both local and systemic necrotic responses, which confine the virus to the infected cells and can also provide resistance to distal, noninfected parts of the organism. Systemic necrosis, which is regarded as a special form of the local hypersensitive response, results in necrosis of the apical stem region, usually causing the death of the plant. Here, we provide evidence that the dsRNA-binding protein 2 of Nicotiana benthamiana plays an important role in virus-induced systemic necrosis. Our findings are not only compatible with the recent hypothesis that DRB proteins act as viral invasion sensors but also extends it by proposing that DRBs play a critical role in establishing the dominant antiviral measures that are triggered during virus infection.
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Affiliation(s)
- Károly Fátyol
- Agricultural Biotechnology Institute, National Agricultural Research and Innovation, Gödöllő, Hungary
| | - Katalin Anna Fekete
- Agricultural Biotechnology Institute, National Agricultural Research and Innovation, Gödöllő, Hungary
| | - Márta Ludman
- Agricultural Biotechnology Institute, National Agricultural Research and Innovation, Gödöllő, Hungary
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9
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Sandoval PJ, Santiago J. In Vitro Analytical Approaches to Study Plant Ligand-Receptor Interactions. PLANT PHYSIOLOGY 2020; 182:1697-1712. [PMID: 32034053 PMCID: PMC7140929 DOI: 10.1104/pp.19.01396] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Accepted: 01/30/2020] [Indexed: 05/15/2023]
Abstract
State-of-the-art in vitro methods characterize receptor-ligand interactions, highlighting experiment strategies, advantages and limitations.
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Affiliation(s)
- Pedro Jimenez Sandoval
- The Plant Signaling Mechanisms Laboratory, Department of Plant Molecular Biology, University of Lausanne, 1015 Lausanne, Switzerland
| | - Julia Santiago
- The Plant Signaling Mechanisms Laboratory, Department of Plant Molecular Biology, University of Lausanne, 1015 Lausanne, Switzerland
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10
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Leitão AL, Costa MC, Gabriel AF, Enguita FJ. Interspecies Communication in Holobionts by Non-Coding RNA Exchange. Int J Mol Sci 2020; 21:ijms21072333. [PMID: 32230931 PMCID: PMC7177868 DOI: 10.3390/ijms21072333] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Revised: 03/24/2020] [Accepted: 03/26/2020] [Indexed: 12/18/2022] Open
Abstract
Complex organisms are associations of different cells that coexist and collaborate creating a living consortium, the holobiont. The relationships between the holobiont members are essential for proper homeostasis of the organisms, and they are founded on the establishment of complex inter-connections between all the cells. Non-coding RNAs are regulatory molecules that can also act as communication signals between cells, being involved in either homeostasis or dysbiosis of the holobionts. Eukaryotic and prokaryotic cells can transmit signals via non-coding RNAs while using specific extracellular conveyors that travel to the target cell and can be translated into a regulatory response by dedicated molecular machinery. Within holobionts, non-coding RNA regulatory signaling is involved in symbiotic and pathogenic relationships among the cells. This review analyzes current knowledge regarding the role of non-coding RNAs in cell-to-cell communication, with a special focus on the signaling between cells in multi-organism consortia.
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Affiliation(s)
- Ana Lúcia Leitão
- Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Campus da Caparica, 2829-516 Caparica, Portugal;
- MEtRICs, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Campus da Caparica, 2829-516 Caparica, Portugal
| | - Marina C. Costa
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Av. Prof. Egas Moniz, 1649-028 Lisboa, Portugal; (M.C.C.); (A.F.G.)
| | - André F. Gabriel
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Av. Prof. Egas Moniz, 1649-028 Lisboa, Portugal; (M.C.C.); (A.F.G.)
| | - Francisco J. Enguita
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Av. Prof. Egas Moniz, 1649-028 Lisboa, Portugal; (M.C.C.); (A.F.G.)
- Correspondence: ; Tel.: +351-217999480
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11
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Ankush Jagtap PK, Müller M, Masiewicz P, von Bülow S, Hollmann NM, Chen PC, Simon B, Thomae AW, Becker PB, Hennig J. Structure, dynamics and roX2-lncRNA binding of tandem double-stranded RNA binding domains dsRBD1,2 of Drosophila helicase Maleless. Nucleic Acids Res 2019; 47:4319-4333. [PMID: 30805612 PMCID: PMC6486548 DOI: 10.1093/nar/gkz125] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Revised: 01/31/2019] [Accepted: 02/22/2019] [Indexed: 12/19/2022] Open
Abstract
Maleless (MLE) is an evolutionary conserved member of the DExH family of helicases in Drosophila. Besides its function in RNA editing and presumably siRNA processing, MLE is best known for its role in remodelling non-coding roX RNA in the context of X chromosome dosage compensation in male flies. MLE and its human orthologue, DHX9 contain two tandem double-stranded RNA binding domains (dsRBDs) located at the N-terminal region. The two dsRBDs are essential for localization of MLE at the X-territory and it is presumed that this involves binding roX secondary structures. However, for dsRBD1 roX RNA binding has so far not been described. Here, we determined the solution NMR structure of dsRBD1 and dsRBD2 of MLE in tandem and investigated its role in double-stranded RNA (dsRNA) binding. Our NMR and SAXS data show that both dsRBDs act as independent structural modules in solution and are canonical, non-sequence-specific dsRBDs featuring non-canonical KKxAXK RNA binding motifs. NMR titrations combined with filter binding experiments and isothermal titration calorimetry (ITC) document the contribution of dsRBD1 to dsRNA binding in vitro. Curiously, dsRBD1 mutants in which dsRNA binding in vitro is strongly compromised do not affect roX2 RNA binding and MLE localization in cells. These data suggest alternative functions for dsRBD1 in vivo.
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Affiliation(s)
- Pravin Kumar Ankush Jagtap
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL) Heidelberg, 69117 Heidelberg, Germany
| | - Marisa Müller
- Biomedical Center and Center for Integrated Protein Science, Ludwig-Maximilians-University, 82152 Martinsried, Germany
| | - Pawel Masiewicz
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL) Heidelberg, 69117 Heidelberg, Germany
| | - Sören von Bülow
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL) Heidelberg, 69117 Heidelberg, Germany
| | - Nele Merret Hollmann
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL) Heidelberg, 69117 Heidelberg, Germany.,Collaboration for joint PhD degree between EMBL and Heidelberg University, Faculty of Biosciences
| | - Po-Chia Chen
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL) Heidelberg, 69117 Heidelberg, Germany
| | - Bernd Simon
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL) Heidelberg, 69117 Heidelberg, Germany
| | - Andreas W Thomae
- Biomedical Center and Center for Integrated Protein Science, Ludwig-Maximilians-University, 82152 Martinsried, Germany
| | - Peter B Becker
- Biomedical Center and Center for Integrated Protein Science, Ludwig-Maximilians-University, 82152 Martinsried, Germany
| | - Janosch Hennig
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL) Heidelberg, 69117 Heidelberg, Germany
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