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Nikovics K, Favier AL, Rocher M, Mayinga C, Gomez J, Dufour-Gaume F, Riccobono D. In Situ Identification of Both IL-4 and IL-10 Cytokine-Receptor Interactions during Tissue Regeneration. Cells 2023; 12:1522. [PMID: 37296643 PMCID: PMC10253026 DOI: 10.3390/cells12111522] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 05/19/2023] [Accepted: 05/24/2023] [Indexed: 06/12/2023] Open
Abstract
Cytokines secreted by individual immune cells regulate tissue regeneration and allow communication between various cell types. Cytokines bind to cognate receptors and trigger the healing process. Determining the orchestration of cytokine interactions with their receptors on their cellular targets is essential to fully understanding the process of inflammation and tissue regeneration. To this end, we have investigated the interactions of Interleukin-4 cytokine (IL-4)/Interleukin-4 cytokine receptor (IL-4R) and Interleukin-10 cytokine (IL-10)/Interleukin-10 cytokine receptor (IL-10R) using in situ Proximity Ligation Assays in a regenerative model of skin, muscle and lung tissues in the mini-pig. The pattern of protein-protein interactions was distinct for the two cytokines. IL-4 bound predominantly to receptors on macrophages and endothelial cells around the blood vessels while the target cells of IL-10 were mainly receptors on muscle cells. Our results show that in situ studies of cytokine-receptor interactions can unravel the fine details of the mechanism of action of cytokines.
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Affiliation(s)
- Krisztina Nikovics
- Imagery Unit, Department of Platforms and Technology Research, French Armed Forces Biomedical Research Institute, 91223 Brétigny-sur-Orge, France; (A.-L.F.); (M.R.); (C.M.); (J.G.)
| | - Anne-Laure Favier
- Imagery Unit, Department of Platforms and Technology Research, French Armed Forces Biomedical Research Institute, 91223 Brétigny-sur-Orge, France; (A.-L.F.); (M.R.); (C.M.); (J.G.)
| | - Mathilde Rocher
- Imagery Unit, Department of Platforms and Technology Research, French Armed Forces Biomedical Research Institute, 91223 Brétigny-sur-Orge, France; (A.-L.F.); (M.R.); (C.M.); (J.G.)
| | - Céline Mayinga
- Imagery Unit, Department of Platforms and Technology Research, French Armed Forces Biomedical Research Institute, 91223 Brétigny-sur-Orge, France; (A.-L.F.); (M.R.); (C.M.); (J.G.)
| | - Johanna Gomez
- Imagery Unit, Department of Platforms and Technology Research, French Armed Forces Biomedical Research Institute, 91223 Brétigny-sur-Orge, France; (A.-L.F.); (M.R.); (C.M.); (J.G.)
| | - Frédérique Dufour-Gaume
- War Traumatology Unit, Department of NRBC Defense, French Armed Forces Biomedical Research Institute, 91223 Brétigny-sur-Orge, France;
| | - Diane Riccobono
- Department of Radiation Bioeffects, French Armed Forces Biomedical Research Institute, 1, Place du Général Valérie André, 91223 Brétigny-sur-Orge, France;
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Favier AL, Nikovics K. Molecular and Cellular Mechanisms of Inflammation and Tissue Regeneration. Biomedicines 2023; 11:biomedicines11051416. [PMID: 37239087 DOI: 10.3390/biomedicines11051416] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Accepted: 05/09/2023] [Indexed: 05/28/2023] Open
Abstract
Over the past 70 years, significant progress has been made in understanding the molecular and cellular mechanisms of inflammation and tissue regeneration [...].
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Affiliation(s)
- Anne-Laure Favier
- Imagery Unit, Department of Platforms and Technology Research, French Armed Forces Biomedical Research Institute, 91223 Bretigny sur Orge, France
| | - Krisztina Nikovics
- Imagery Unit, Department of Platforms and Technology Research, French Armed Forces Biomedical Research Institute, 91223 Bretigny sur Orge, France
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Durand M, Oger M, Nikovics K, Venant J, Guillope AC, Jouve E, Barbier L, Bégot L, Poirier F, Rousseau C, Pitois O, Mathieu L, Favier AL, Lutomski D, Collombet JM. Influence of the Immune Microenvironment Provided by Implanted Biomaterials on the Biological Properties of Masquelet-Induced Membranes in Rats: Metakaolin as an Alternative Spacer. Biomedicines 2022; 10:biomedicines10123017. [PMID: 36551773 PMCID: PMC9776074 DOI: 10.3390/biomedicines10123017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Revised: 11/16/2022] [Accepted: 11/17/2022] [Indexed: 11/25/2022] Open
Abstract
Macrophages play a key role in the inflammatory phase of wound repair and foreign body reactions-two important processes in the Masquelet-induced membrane technique for extremity reconstruction. The macrophage response depends largely on the nature of the biomaterials implanted. However, little is known about the influence of the macrophage microenvironment on the osteogenic properties of the induced membrane or subsequent bone regeneration. We used metakaolin, an immunogenic material, as an alternative spacer to standard polymethylmethacrylate (PMMA) in a Masquelet model in rats. Four weeks after implantation, the PMMA- and metakaolin-induced membranes were harvested, and their osteogenic properties and macrophage microenvironments were investigated by histology, immunohistochemistry, mass spectroscopy and gene expression analysis. The metakaolin spacer induced membranes with higher levels of two potent pro-osteogenic factors, transforming growth factor-β (TGF-β) and bone morphogenic protein-2 (BMP-2). These alternative membranes thus had greater osteogenic activity, which was accompanied by a significant expansion of the total macrophage population, including both the M1-like and M2-like subtypes. Microcomputed tomographic analysis showed that metakaolin-induced membranes supported bone regeneration more effectively than PMMA-induced membranes through better callus properties (+58%), although this difference was not significant. This study provides the first evidence of the influence of the immune microenvironment on the osteogenic properties of the induced membranes.
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Affiliation(s)
- Marjorie Durand
- Osteo-Articulary Biotherapy Unit, Department of Medical and Surgical Assistance to the Armed Forces, French Armed Forces Biomedical Research Institute, 91223 Brétigny-sur-Orge, France
- Correspondence:
| | - Myriam Oger
- Imaging Unit, Department of Platforms and Technology Research, French Armed Forces Biomedical Research Institute, 91223 Brétigny-sur-Orge, France
| | - Krisztina Nikovics
- Imaging Unit, Department of Platforms and Technology Research, French Armed Forces Biomedical Research Institute, 91223 Brétigny-sur-Orge, France
| | - Julien Venant
- Osteo-Articulary Biotherapy Unit, Department of Medical and Surgical Assistance to the Armed Forces, French Armed Forces Biomedical Research Institute, 91223 Brétigny-sur-Orge, France
- Tissue Engineering Research Unit-URIT, Sorbonne Paris Nord University, 93000 Bobigny, France
| | - Anne-Cecile Guillope
- Osteo-Articulary Biotherapy Unit, Department of Medical and Surgical Assistance to the Armed Forces, French Armed Forces Biomedical Research Institute, 91223 Brétigny-sur-Orge, France
| | - Eugénie Jouve
- Osteo-Articulary Biotherapy Unit, Department of Medical and Surgical Assistance to the Armed Forces, French Armed Forces Biomedical Research Institute, 91223 Brétigny-sur-Orge, France
| | - Laure Barbier
- Molecular Biology Unit, Department of Platforms and Technology Research, French Armed Forces Biomedical Research Institute, 91223 Brétigny-sur-Orge, France
| | - Laurent Bégot
- Imaging Unit, Department of Platforms and Technology Research, French Armed Forces Biomedical Research Institute, 91223 Brétigny-sur-Orge, France
| | - Florence Poirier
- Tissue Engineering Research Unit-URIT, Sorbonne Paris Nord University, 93000 Bobigny, France
| | - Catherine Rousseau
- Molecular Biology Unit, Department of Platforms and Technology Research, French Armed Forces Biomedical Research Institute, 91223 Brétigny-sur-Orge, France
| | - Olivier Pitois
- Laboratoire Navier, Gustave Eiffel University, Ecole des Ponts ParisTech, CNRS, 77447 Marne-la-Vallée, France
| | - Laurent Mathieu
- Osteo-Articulary Biotherapy Unit, Department of Medical and Surgical Assistance to the Armed Forces, French Armed Forces Biomedical Research Institute, 91223 Brétigny-sur-Orge, France
- Department of Surgery, Ecole du Val-de-Grace, French Military Health Service Academy, 1 Place Alphonse Laveran, 75005 Paris, France
| | - Anne-Laure Favier
- Imaging Unit, Department of Platforms and Technology Research, French Armed Forces Biomedical Research Institute, 91223 Brétigny-sur-Orge, France
| | - Didier Lutomski
- Tissue Engineering Research Unit-URIT, Sorbonne Paris Nord University, 93000 Bobigny, France
| | - Jean-Marc Collombet
- Osteo-Articulary Biotherapy Unit, Department of Medical and Surgical Assistance to the Armed Forces, French Armed Forces Biomedical Research Institute, 91223 Brétigny-sur-Orge, France
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Nikovics K, Durand M, Castellarin C, Burger J, Sicherre E, Collombet JM, Oger M, Holy X, Favier AL. Macrophages Characterization in an Injured Bone Tissue. Biomedicines 2022; 10:biomedicines10061385. [PMID: 35740407 PMCID: PMC9219779 DOI: 10.3390/biomedicines10061385] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Accepted: 06/08/2022] [Indexed: 11/16/2022] Open
Abstract
Biomaterial use is a promising approach to facilitate wound healing of the bone tissue. Biomaterials induce the formation of membrane capsules and the recruitment of different types of macrophages. Macrophages are immune cells that produce diverse combinations of cytokines playing an important role in bone healing and regeneration, but the exact mechanism remains to be studied. Our work aimed to identify in vivo macrophages in the Masquelet induced membrane in a rat model. Most of the macrophages in the damaged area were M2-like, with smaller numbers of M1-like macrophages. In addition, high expression of IL-1β and IL-6 cytokines were detected in the membrane region by RT-qPCR. Using an innovative combination of two hybridization techniques (in situ hybridization and in situ hybridization chain reaction (in situ HCR)), M2b-like macrophages were identified for the first time in cryosections of non-decalcified bone. Our work has also demonstrated that microspectroscopical analysis is essential for macrophage characterization, as it allows the discrimination of fluorescence and autofluorescence. Finally, this work has revealed the limitations of immunolabelling and the potential of in situ HCR to provide valuable information for in vivo characterization of macrophages.
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Affiliation(s)
- Krisztina Nikovics
- Imagery Unit, Department of Platforms and Technology Research, French Armed Forces Biomedical Research Institute, 91223 Brétigny-sur-Orge, France; (C.C.); (E.S.); (M.O.); (A.-L.F.)
- Correspondence: or ; Tel.: +33-(0)-1-78-65-13-331
| | - Marjorie Durand
- Osteo-Articulary Biotherapy Unit, Department of Medical and Surgical Assistance to the Armed Forces, French Armed Forces Biomedical Research Institute, 91223 Brétigny-sur-Orge, France; (M.D.); (J.-M.C.)
| | - Cédric Castellarin
- Imagery Unit, Department of Platforms and Technology Research, French Armed Forces Biomedical Research Institute, 91223 Brétigny-sur-Orge, France; (C.C.); (E.S.); (M.O.); (A.-L.F.)
| | - Julien Burger
- Microbiology and Infectious Diseases Department, French Armed Forces Biomedical Research Institute, 91223 Brétigny-sur-Orge, France;
| | - Emma Sicherre
- Imagery Unit, Department of Platforms and Technology Research, French Armed Forces Biomedical Research Institute, 91223 Brétigny-sur-Orge, France; (C.C.); (E.S.); (M.O.); (A.-L.F.)
| | - Jean-Marc Collombet
- Osteo-Articulary Biotherapy Unit, Department of Medical and Surgical Assistance to the Armed Forces, French Armed Forces Biomedical Research Institute, 91223 Brétigny-sur-Orge, France; (M.D.); (J.-M.C.)
| | - Myriam Oger
- Imagery Unit, Department of Platforms and Technology Research, French Armed Forces Biomedical Research Institute, 91223 Brétigny-sur-Orge, France; (C.C.); (E.S.); (M.O.); (A.-L.F.)
| | - Xavier Holy
- Department of Platforms and Technology Research, French Armed Forces Biomedical Research Institute, 91223 Brétigny-sur-Orge, France;
| | - Anne-Laure Favier
- Imagery Unit, Department of Platforms and Technology Research, French Armed Forces Biomedical Research Institute, 91223 Brétigny-sur-Orge, France; (C.C.); (E.S.); (M.O.); (A.-L.F.)
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Abstract
Understanding the processes of inflammation and tissue regeneration after injury is of great importance. For a long time, macrophages have been known to play a central role during different stages of inflammation and tissue regeneration. However, the molecular and cellular mechanisms by which they exert their effects are as yet mostly unknown. While in vitro macrophages have been characterized, recent progress in macrophage biology studies revealed that macrophages in vivo exhibited distinctive features. Actually, the precise characterization of the macrophages in vivo is essential to develop new healing treatments and can be approached via in situ analyses. Nowadays, the characterization of macrophages in situ has improved significantly using antigen surface markers and cytokine secretion identification resulting in specific patterns. This review aims for a comprehensive overview of different tools used for in situ macrophage identification, reporter genes, immunolabeling and in situ hybridization, discussing their advantages and limitations.
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Sicherre E, Favier AL, Riccobono D, Nikovics K. Non-Specific Binding, a Limitation of the Immunofluorescence Method to Study Macrophages In Situ. Genes (Basel) 2021; 12:649. [PMID: 33925331 PMCID: PMC8145419 DOI: 10.3390/genes12050649] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Revised: 04/20/2021] [Accepted: 04/26/2021] [Indexed: 12/24/2022] Open
Abstract
Advances in understanding tissue regenerative mechanisms require the characterization of in vivo macrophages as those play a fundamental role in this process. This characterization can be approached using the immuno-fluorescence method with widely studied and used pan-markers such as CD206 protein. This work investigated CD206 expression in an irradiated-muscle pig model using three different antibodies. Surprisingly, the expression pattern during immunodetection differed depending on the antibody origin and could give some false results. False results are rarely described in the literature, but this information is essential for scientists who need to characterize macrophages. In this context, we showed that in situ hybridization coupled with hybridization-chain-reaction detection (HCR) is an excellent alternative method to detect macrophages in situ.
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Affiliation(s)
- Emma Sicherre
- Imagery Unit, Department of Platforms and Technology Research, French Armed Forces Biomedical Research Institute, 91223 Brétigny-sur-Orge, France; (E.S.); (A.-L.F.)
| | - Anne-Laure Favier
- Imagery Unit, Department of Platforms and Technology Research, French Armed Forces Biomedical Research Institute, 91223 Brétigny-sur-Orge, France; (E.S.); (A.-L.F.)
| | - Diane Riccobono
- Radiobiology Unit, Department of NRBC Defence, French Armed Forces Biomedical Research Institute, 91223 Brétigny-sur-Orge, France;
| | - Krisztina Nikovics
- Imagery Unit, Department of Platforms and Technology Research, French Armed Forces Biomedical Research Institute, 91223 Brétigny-sur-Orge, France; (E.S.); (A.-L.F.)
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Nikovics K, Morin H, Riccobono D, Bendahmane A, Favier AL. Hybridization-chain-reaction is a relevant method for in situ detection of M2d-like macrophages in a mini-pig model. FASEB J 2020; 34:15675-15686. [PMID: 33078886 DOI: 10.1096/fj.202001496r] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2020] [Revised: 09/20/2020] [Accepted: 09/28/2020] [Indexed: 12/18/2022]
Abstract
Macrophages are a heterogeneous population of cells with an important role in innate immunity and tissue regeneration. Based on in vitro experiments, macrophages have been subdivided into five distinct subtypes named M1, M2a, M2b, M2c, and M2d, depending on the means of their activation and the cell surface markers they display. Whether all subtypes can be detected in vivo is still unclear. The identification of macrophages in vivo in the regenerating muscle could be used as a new diagnostic tool to monitor therapeutic strategies for tissue repair. The use of classical immunolabeling techniques is unable to discriminate between different M2 macrophages and a functional characterization of these macrophages is lacking. Using in situ hybridization coupled with hybridization-chain-reaction detection (HCR), we achieved the identification of M2d-like macrophages within regenerating muscle and applied this technique to understand the role of M2 macrophages in the regeneration of irradiated pig-muscle after adipose tissue stem cell treatment. Our work highlights the limits of immunolabeling and the usefulness of HCR analysis to provide valuable information for macrophage characterization.
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Affiliation(s)
- Krisztina Nikovics
- Imagery Unit, Department of Platforms and Technology Research, French Armed Forces Biomedical Research Institute, Brétigny-sur-Orge Cedex, France
| | - Halima Morin
- Institute of Plant Sciences Paris-Saclay (IPS2), University Paris-Saclay, INRAE, CNRS, Univ Evry, Orsay, France
| | - Diane Riccobono
- Radiobiology Unit, Department of NRBC Defens, French Armed Forces Biomedical Research Institute, Brétigny-sur-Orge Cedex, France
| | - Abdelhafid Bendahmane
- Institute of Plant Sciences Paris-Saclay (IPS2), University Paris-Saclay, INRAE, CNRS, Univ Evry, Orsay, France
| | - Anne-Laure Favier
- Imagery Unit, Department of Platforms and Technology Research, French Armed Forces Biomedical Research Institute, Brétigny-sur-Orge Cedex, France
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Riccobono D, Nikovics K, François S, Favier AL, Jullien N, Schrock G, Scherthan H, Drouet M. First Insights Into the M2 Inflammatory Response After Adipose-Tissue-Derived Stem Cell Injections in Radiation-Injured Muscles. Health Phys 2018; 115:37-48. [PMID: 29787429 DOI: 10.1097/hp.0000000000000822] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The cutaneous radiation syndrome is the clinical consequence of local high-dose irradiation. It is characterized by extensive inflammation, necrosis, and poor revascularization of the skin, resulting in muscle inflammation and fibrosis. Based on these physiopathological processes, subcutaneous injections of adipose-tissue-derived stem/stromal cells have shown favorable effects on skin-wound healing in a minipig model of cutaneous radiation syndrome, in which muscle fibrosis persisted. Since fibrosis is mainly due to the inflammatory processes that often affect underlying tissues as well, the beneficial effects of intramuscular injections of adipose-tissue-derived stem/stromal cells on tissue recovery were evaluated. The polarization of the inflammatory response of irradiated muscle in a minipig model of cutaneous radiation syndrome was determined after acute local irradiation with 50 Gy gamma rays in a preliminary study (six minipigs). Analysis of the main inflammatory cytokines of the inflammatory response M1 (IL-1-beta and IL-6) and M2 (IL-10 and TGF-beta) by western blotting and in situ hybridization, as well as analysis of CD80/CD206 M1/M2 macrophage-specific markers by immunohistochemistry on minipig muscle samples, was performed 76 d after irradiation. The treatment of irradiated muscles with autologous adipose-tissue-derived stem/stromal cells led to an increase in IL-10 and TGF-beta, being associated with an increase in CD68+/CD206+ cells in this area. This highlights a polarization of M2 in the inflammatory response and indicates that adipose-tissue-derived stem/stromal cells may direct the irradiated tissues' inflammatory response towards a proregenerative outcome.
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Affiliation(s)
- Diane Riccobono
- Institut de Recherche Biomédicale des Armées (IRBA), Unité de Radiobiologie, Brétigny sur Orge Cedex, France
| | - Krisztina Nikovics
- Institut de Recherche Biomédicale des Armées (IRBA), Département des Services, Unité Imagerie, Brétigny sur Orge Cedex, France
| | - Sabine François
- Institut de Recherche Biomédicale des Armées (IRBA), Unité de Radiobiologie, Brétigny sur Orge Cedex, France
| | - Anne-Laure Favier
- Institut de Recherche Biomédicale des Armées (IRBA), Département des Services, Unité Imagerie, Brétigny sur Orge Cedex, France
| | - Nicolas Jullien
- Institut de Recherche Biomédicale des Armées (IRBA), Unité de Radiobiologie, Brétigny sur Orge Cedex, France
| | - Gerrit Schrock
- Institut für Radiobiologie der Bundeswehr, Neuherbergstraße 11, 80937 München, Germany
| | - Harry Scherthan
- Institut für Radiobiologie der Bundeswehr, Neuherbergstraße 11, 80937 München, Germany
| | - Michel Drouet
- Institut de Recherche Biomédicale des Armées (IRBA), Unité de Radiobiologie, Brétigny sur Orge Cedex, France
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Gonçalves B, Hasson A, Belcram K, Cortizo M, Morin H, Nikovics K, Vialette-Guiraud A, Takeda S, Aida M, Laufs P, Arnaud N. A conserved role for CUP-SHAPED COTYLEDON genes during ovule development. Plant J 2015; 83:732-42. [PMID: 26119568 DOI: 10.1111/tpj.12923] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2015] [Revised: 06/18/2015] [Accepted: 06/23/2015] [Indexed: 05/03/2023]
Abstract
The evolution of plant reproductive strategies has led to a remarkable diversity of structures, especially within the flower, a structure characteristic of the angiosperms. In flowering plants, sexual reproduction depends notably on the development of the gynoecium that produces and protects the ovules. In Arabidopsis thaliana, ovule initiation is promoted by the concerted action of auxin with CUC1 (CUP-SHAPED COTYLEDON1) and CUC2, two genes that encode transcription factors of the NAC family (NAM/ATAF1,2/CUC). Here we highlight an additional role for CUC2 and CUC3 in Arabidopsis thaliana ovule separation. While CUC1 and CUC2 are broadly expressed in the medial tissue of the gynoecium, CUC2 and CUC3 are expressed in the placental tissue between developing ovules. Consistent with the partial overlap between CUC1, CUC2 and CUC3 expression patterns, we show that CUC proteins can physically interact, both in yeast cells and in planta. We found that the cuc2;cuc3 double mutant specifically harbours defects in ovule separation, producing fused seeds that share the seed coat, and suggesting that CUC2 and CUC3 promote ovule separation in a partially redundant manner. Functional analyses show that CUC transcription factors are also involved in ovule development in Cardamine hirsuta. Additionally we show a conserved expression pattern of CUC orthologues between ovule primordia in other phylogenetically distant species with different gynoecium architectures. Taken together these results suggest an ancient role for CUC transcription factors in ovule separation, and shed light on the conservation of mechanisms involved in the development of innovative structures.
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Affiliation(s)
- Beatriz Gonçalves
- INRA, Institut Jean-Pierre Bourgin, UMR 1318, ERL CNRS 3559, Saclay Plant Sciences, RD10, F-78026, Versailles, France
- AgroParisTech, Institut Jean-Pierre Bourgin, UMR 1318, ERL CNRS 3559, Saclay Plant Sciences, RD10, F-78026, Versailles, France
| | - Alice Hasson
- INRA, Institut Jean-Pierre Bourgin, UMR 1318, ERL CNRS 3559, Saclay Plant Sciences, RD10, F-78026, Versailles, France
- AgroParisTech, Institut Jean-Pierre Bourgin, UMR 1318, ERL CNRS 3559, Saclay Plant Sciences, RD10, F-78026, Versailles, France
| | - Katia Belcram
- INRA, Institut Jean-Pierre Bourgin, UMR 1318, ERL CNRS 3559, Saclay Plant Sciences, RD10, F-78026, Versailles, France
- AgroParisTech, Institut Jean-Pierre Bourgin, UMR 1318, ERL CNRS 3559, Saclay Plant Sciences, RD10, F-78026, Versailles, France
| | - Millán Cortizo
- INRA, Institut Jean-Pierre Bourgin, UMR 1318, ERL CNRS 3559, Saclay Plant Sciences, RD10, F-78026, Versailles, France
- AgroParisTech, Institut Jean-Pierre Bourgin, UMR 1318, ERL CNRS 3559, Saclay Plant Sciences, RD10, F-78026, Versailles, France
| | - Halima Morin
- INRA, Institut Jean-Pierre Bourgin, UMR 1318, ERL CNRS 3559, Saclay Plant Sciences, RD10, F-78026, Versailles, France
- AgroParisTech, Institut Jean-Pierre Bourgin, UMR 1318, ERL CNRS 3559, Saclay Plant Sciences, RD10, F-78026, Versailles, France
| | - Krisztina Nikovics
- INRA, Institut Jean-Pierre Bourgin, UMR 1318, ERL CNRS 3559, Saclay Plant Sciences, RD10, F-78026, Versailles, France
- AgroParisTech, Institut Jean-Pierre Bourgin, UMR 1318, ERL CNRS 3559, Saclay Plant Sciences, RD10, F-78026, Versailles, France
| | - Aurélie Vialette-Guiraud
- INRA, Institut Jean-Pierre Bourgin, UMR 1318, ERL CNRS 3559, Saclay Plant Sciences, RD10, F-78026, Versailles, France
- AgroParisTech, Institut Jean-Pierre Bourgin, UMR 1318, ERL CNRS 3559, Saclay Plant Sciences, RD10, F-78026, Versailles, France
| | - Seiji Takeda
- Cell and Genome Biology, Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Kitaina-Yazuma Oji 74, Seika, Soraku, Kyoto, 619-0244, Japan
| | - Mitsuhiro Aida
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara, 630-0192, Japan
| | - Patrick Laufs
- INRA, Institut Jean-Pierre Bourgin, UMR 1318, ERL CNRS 3559, Saclay Plant Sciences, RD10, F-78026, Versailles, France
- AgroParisTech, Institut Jean-Pierre Bourgin, UMR 1318, ERL CNRS 3559, Saclay Plant Sciences, RD10, F-78026, Versailles, France
| | - Nicolas Arnaud
- INRA, Institut Jean-Pierre Bourgin, UMR 1318, ERL CNRS 3559, Saclay Plant Sciences, RD10, F-78026, Versailles, France
- AgroParisTech, Institut Jean-Pierre Bourgin, UMR 1318, ERL CNRS 3559, Saclay Plant Sciences, RD10, F-78026, Versailles, France
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Troncoso-Ponce MA, Nikovics K, Marchive C, Lepiniec L, Baud S. New insights on the organization and regulation of the fatty acid biosynthetic network in the model higher plant Arabidopsis thaliana. Biochimie 2015; 120:3-8. [PMID: 26025475 DOI: 10.1016/j.biochi.2015.05.013] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Accepted: 05/06/2015] [Indexed: 01/07/2023]
Abstract
In the plastids of plant cells, fatty acid (FA) production is a central biosynthetic process. It provides acyl chains for the formation of a variety of acyl lipids fulfilling different biological functions ranging from membrane synthesis to signaling or carbon and energy storage. The biochemical pathway leading to the synthesis of FA has been described for a long time. Over the last 15 years, and after the genome of the model higher plant Arabidopsis thaliana has been sequenced, the scientific community has deployed approaches of functional genomics to identify the actors comprising this pathway. One of the puzzling aspects of the emerging molecular biology of FA synthesis resided in the occurrence of multigene families encoding most enzymes of the pathway. Studies carried out to investigate these families led to the conclusion that most members have acquired non-redundant roles in planta. This is usually the consequence of divergent expression patterns of these isogenes and/or of different substrate specificities of the isoforms they encode. Nevertheless, much remains to be elucidated regarding the molecular bases underpinning these specificities. Protein biochemistry together with emerging quantitative proteomic technologies have then led to a better understanding of the structure of the network, which is composed of multiprotein complexes organized within the stromal compartment of plastids: whereas growing evidence suggests that the early steps of the pathway might be associated to the inner envelope membrane, several late enzymes might be localized next to the thylakoids. The question of the existence of a large integrated protein assembly channeling substrates through the whole pathway that would span the stroma remains uncertain. Finally, recent discoveries regarding the post-translational regulation of the pathway open new research horizons and may guide the development of relevant biotechnological strategies aimed at monitoring FA production in plant systems.
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Affiliation(s)
- Manuel Adrián Troncoso-Ponce
- INRA, UMR1318, Institut Jean-Pierre Bourgin, Saclay Plant Sciences, RD10, F-78000 Versailles, France; AgroParisTech, UMR1318, Institut Jean-Pierre Bourgin, Saclay Plant Sciences, RD10, F-78000 Versailles, France
| | - Krisztina Nikovics
- INRA, UMR1318, Institut Jean-Pierre Bourgin, Saclay Plant Sciences, RD10, F-78000 Versailles, France; AgroParisTech, UMR1318, Institut Jean-Pierre Bourgin, Saclay Plant Sciences, RD10, F-78000 Versailles, France
| | - Chloé Marchive
- INRA, UMR1318, Institut Jean-Pierre Bourgin, Saclay Plant Sciences, RD10, F-78000 Versailles, France; AgroParisTech, UMR1318, Institut Jean-Pierre Bourgin, Saclay Plant Sciences, RD10, F-78000 Versailles, France
| | - Loïc Lepiniec
- INRA, UMR1318, Institut Jean-Pierre Bourgin, Saclay Plant Sciences, RD10, F-78000 Versailles, France; AgroParisTech, UMR1318, Institut Jean-Pierre Bourgin, Saclay Plant Sciences, RD10, F-78000 Versailles, France
| | - Sébastien Baud
- INRA, UMR1318, Institut Jean-Pierre Bourgin, Saclay Plant Sciences, RD10, F-78000 Versailles, France; AgroParisTech, UMR1318, Institut Jean-Pierre Bourgin, Saclay Plant Sciences, RD10, F-78000 Versailles, France.
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11
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Marchive C, Nikovics K, To A, Lepiniec L, Baud S. Transcriptional regulation of fatty acid production in higher plants: Molecular bases and biotechnological outcomes. EUR J LIPID SCI TECH 2014. [DOI: 10.1002/ejlt.201400027] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- Chloé Marchive
- INRA, UMR1318; Institut Jean-Pierre Bourgin; Saclay Plant Sciences F-78000 Versailles France
- AgroParisTech, UMR1318; Institut Jean-Pierre Bourgin; Saclay Plant Sciences F-78000 Versailles France
| | - Krisztina Nikovics
- INRA, UMR1318; Institut Jean-Pierre Bourgin; Saclay Plant Sciences F-78000 Versailles France
- AgroParisTech, UMR1318; Institut Jean-Pierre Bourgin; Saclay Plant Sciences F-78000 Versailles France
| | - Alexandra To
- INRA, UMR1318; Institut Jean-Pierre Bourgin; Saclay Plant Sciences F-78000 Versailles France
- AgroParisTech, UMR1318; Institut Jean-Pierre Bourgin; Saclay Plant Sciences F-78000 Versailles France
| | - Loïc Lepiniec
- INRA, UMR1318; Institut Jean-Pierre Bourgin; Saclay Plant Sciences F-78000 Versailles France
- AgroParisTech, UMR1318; Institut Jean-Pierre Bourgin; Saclay Plant Sciences F-78000 Versailles France
| | - Sébastien Baud
- INRA, UMR1318; Institut Jean-Pierre Bourgin; Saclay Plant Sciences F-78000 Versailles France
- AgroParisTech, UMR1318; Institut Jean-Pierre Bourgin; Saclay Plant Sciences F-78000 Versailles France
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12
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Müller B, Anders M, Akiyama H, Welsch S, Glass B, Nikovics K, Clavel F, Tervo HM, Keppler OT, Kräusslich HG. HIV-1 Gag processing intermediates trans-dominantly interfere with HIV-1 infectivity. J Biol Chem 2009; 284:29692-703. [PMID: 19666477 DOI: 10.1074/jbc.m109.027144] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Protease inhibitors (PI) act by blocking human immunodeficiency virus (HIV) polyprotein processing, but there is no direct quantitative correlation between the degree of impairment of Gag processing and virion infectivity at low PI concentrations. To analyze the consequences of partial processing, virus particles were produced in the presence of limiting PI concentrations or by co-transfection of wild-type proviral plasmids with constructs carrying mutations in one or more cleavage sites. Low PI concentrations caused subtle changes in polyprotein processing associated with a pronounced reduction of particle infectivity. Dissection of individual stages of viral entry indicated a block in accumulation of reverse transcriptase products, whereas virus entry, enzymatic reverse transcriptase activity, and replication steps following reverse transcription were not affected. Co-expression of low amounts of partially processed forms of Gag together with wild-type HIV generally exerted a trans-dominant effect, which was most prominent for a construct carrying mutations at both cleavage sites flanking the CA domain. Interestingly, co-expression of low amounts of Gag mutated at the CA-SP1 cleavage site also affected processing activity at this site in the wild-type virus. The results indicate that low amounts (<5%) of Gag processing intermediates can display a trans-dominant effect on HIV particle maturation, with the maturation cleavage between CA and SP1 being of particular importance. These effects are likely to be important for the strong activity of PI at concentrations achieved in vivo and also bear relevance for the mechanism of action of the antiviral drug bevirimat.
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Affiliation(s)
- Barbara Müller
- Department of Virology, Universitätsklinikum Heidelberg, Im Neuenheimer Feld 324, D-69120 Heidelberg, Germany.
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13
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Blein T, Pulido A, Vialette-Guiraud A, Nikovics K, Morin H, Hay A, Johansen IE, Tsiantis M, Laufs P. A conserved molecular framework for compound leaf development. Science 2008; 322:1835-9. [PMID: 19095941 DOI: 10.1126/science.1166168] [Citation(s) in RCA: 237] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Diversity in leaf shape is produced by alterations of the margin: for example, deep dissection leads to leaflet formation and less-pronounced incision results in serrations or lobes. By combining gene silencing and mutant analyses in four distantly related eudicot species, we show that reducing the function of NAM/CUC boundary genes (NO APICAL MERISTEM and CUP-SHAPED COTYLEDON) leads to a suppression of all marginal outgrowths and to fewer and fused leaflets. We propose that NAM/CUC genes promote formation of a boundary domain that delimits leaflets. This domain has a dual role promoting leaflet separation locally and leaflet formation at distance. In this manner, boundaries of compound leaves resemble boundaries functioning during animal development.
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Affiliation(s)
- Thomas Blein
- Laboratoire de Biologie Cellulaire, Institut Jean Pierre Bourgin, Institut National de la Recherche Agronomique (INRA), 78026 Versailles Cedex, France
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14
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Belov GA, Feng Q, Nikovics K, Jackson CL, Ehrenfeld E. A critical role of a cellular membrane traffic protein in poliovirus RNA replication. PLoS Pathog 2008; 4:e1000216. [PMID: 19023417 PMCID: PMC2581890 DOI: 10.1371/journal.ppat.1000216] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2008] [Accepted: 10/23/2008] [Indexed: 12/12/2022] Open
Abstract
Replication of many RNA viruses is accompanied by extensive remodeling of intracellular membranes. In poliovirus-infected cells, ER and Golgi stacks disappear, while new clusters of vesicle-like structures form sites for viral RNA synthesis. Virus replication is inhibited by brefeldin A (BFA), implicating some components(s) of the cellular secretory pathway in virus growth. Formation of characteristic vesicles induced by expression of viral proteins was not inhibited by BFA, but they were functionally deficient. GBF1, a guanine nucleotide exchange factor for the small cellular GTPases, Arf, is responsible for the sensitivity of virus infection to BFA, and is required for virus replication. Knockdown of GBF1 expression inhibited virus replication, which was rescued by catalytically active protein with an intact N-terminal sequence. We identified a mutation in GBF1 that allows growth of poliovirus in the presence of BFA. Interaction between GBF1 and viral protein 3A determined the outcome of infection in the presence of BFA.
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Affiliation(s)
- George A. Belov
- National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Qian Feng
- National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Krisztina Nikovics
- Laboratoire d'Enzymologie et Biochimie Structurales, CNRS, Gif-sur-Yvette, France
| | - Catherine L. Jackson
- Laboratoire d'Enzymologie et Biochimie Structurales, CNRS, Gif-sur-Yvette, France
| | - Ellie Ehrenfeld
- National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
- * E-mail:
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15
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Nikovics K, Blein T, Peaucelle A, Ishida T, Morin H, Aida M, Laufs P. The balance between the MIR164A and CUC2 genes controls leaf margin serration in Arabidopsis. Plant Cell 2006; 18:2929-45. [PMID: 17098808 PMCID: PMC1693934 DOI: 10.1105/tpc.106.045617] [Citation(s) in RCA: 397] [Impact Index Per Article: 22.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/14/2023]
Abstract
CUP-SHAPED COTYLEDON1 (CUC1), CUC2, and CUC3 define the boundary domain around organs in the Arabidopsis thaliana meristem. CUC1 and CUC2 transcripts are targeted by a microRNA (miRNA), miR164, encoded by MIR164A, B, and C. We show that each MIR164 is transcribed to generate a large population of primary miRNAs of variable size with a locally conserved secondary structure around the pre-miRNA. We identified mutations in the MIR164A gene that deepen serration of the leaf margin. By contrast, leaves of plants overexpressing miR164 have smooth margins. Enhanced leaf serration was observed following the expression of an miR164-resistant CUC2 but not of an miR164-resistant CUC1. Furthermore, CUC2 inactivation abolished serration in mir164a mutants and the wild type, whereas CUC1 inactivation did not. Thus, CUC2 specifically controls leaf margin development. CUC2 and MIR164A are transcribed in overlapping domains at the margins of young leaf primordia, with transcription gradually restricted to the sinus, where the leaf margins become serrated. We suggest that leaf margin development is controlled by a two-step process in Arabidopsis. The pattern of serration is determined first, independently of CUC2 and miR164. The balance between coexpressed CUC2 and MIR164A then determines the extent of serration.
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Affiliation(s)
- Krisztina Nikovics
- Laboratoire de Biologie Cellulaire, Institut Jean Pierre Bourgin, Institut National de la Recherche Agronomique, 78026 Versailles Cedex, France
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16
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Fülöp K, Tarayre S, Kelemen Z, Horváth G, Kevei Z, Nikovics K, Bakó L, Brown S, Kondorosi A, Kondorosi E. Arabidopsis anaphase-promoting complexes: multiple activators and wide range of substrates might keep APC perpetually busy. Cell Cycle 2005; 4:1084-92. [PMID: 15970679] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/03/2023] Open
Abstract
The anaphase-promoting complex (APC), a multisubunit E3 ubiquitin ligase, is an essential regulator of the cell cycle from metaphase until S phase in yeast and metazoans. APC mediates degradation of numerous cell cycle-related proteins, including mitotic cyclins and its activation and substrate-specificity are determined by two adaptor proteins, Cdc20 and Cdh1. Plants have multiple APC activators and the Cdh1-type proteins, in addition, are represented by two subclasses, known as Ccs52A and Ccs52B. The Arabidopsis genome contains five cdc20 genes as well as ccs52A1, ccs52A2 and ccs52B. In Schizosaccharomyces pombe, expression of the three Atccs52 genes elicited distinct phenotypes supporting nonredundant function of the AtCcs52 proteins. Consistent with these activities, the AtCcs52 proteins were able to bind both to the yeast and the Arabidopsis APCs. In synchronized Arabidopsis cell cultures the cdc20 transcripts were present from early G2 until the M-phase exit, ccs52B from G2/M to M while ccs52A1 and ccs52A2 were from late M until early G2, suggesting consecutive action of these APC activators in the plant cell cycle. The AtCcs52 proteins interacted with different subsets of mitotic cyclins, in accordance with their expression profiles, either in free- or CDK-bound forms. Expression of most APC subunits was constitutive, whereas cdc27a and cdc27b, corresponding to two forms of apc3, and ubc19 and ubc20 encoding E2-C type ubiquitin-conjugating enzymes displayed differences in their cell cycle regulation. These data indicate the existence of numerous APC(Cdc20/Ccs52/Cdc27) forms in Arabidopsis, which in conjunction with different E2 enzymes might have distinct or complementary functions at distinct stages of the cell cycle.
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Affiliation(s)
- Katalin Fülöp
- Institut des Sciences du Végétal, Gif sur Yvette, France
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17
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Fülöp K, Tarayre S, Kelemen Z, Horváth G, Kevei Z, Nikovics K, Bakó L, Brown S, Kondorosi A, Kondorosi E. Arabidopsis Anaphase-Promoting Complexes: Multiple Activators and Wide Range of Substrates Might Keep APC Perpetually Busy. Cell Cycle 2005. [DOI: 10.4161/cc.4.8.1856] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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18
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Mergaert P, Nikovics K, Kelemen Z, Maunoury N, Vaubert D, Kondorosi A, Kondorosi E. A novel family in Medicago truncatula consisting of more than 300 nodule-specific genes coding for small, secreted polypeptides with conserved cysteine motifs. Plant Physiol 2003; 132:161-73. [PMID: 12746522 PMCID: PMC166962 DOI: 10.1104/pp.102.018192] [Citation(s) in RCA: 275] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2002] [Revised: 02/09/2003] [Accepted: 02/09/2003] [Indexed: 05/18/2023]
Abstract
Transcriptome analysis of Medicago truncatula nodules has led to the discovery of a gene family named NCR (nodule-specific cysteine rich) with more than 300 members. The encoded polypeptides were short (60-90 amino acids), carried a conserved signal peptide, and, except for a conserved cysteine motif, displayed otherwise extensive sequence divergence. Family members were found in pea (Pisum sativum), broad bean (Vicia faba), white clover (Trifolium repens), and Galega orientalis but not in other plants, including other legumes, suggesting that the family might be specific for galegoid legumes forming indeterminate nodules. Gene expression of all family members was restricted to nodules except for two, also expressed in mycorrhizal roots. NCR genes exhibited distinct temporal and spatial expression patterns in nodules and, thus, were coupled to different stages of development. The signal peptide targeted the polypeptides in the secretory pathway, as shown by green fluorescent protein fusions expressed in onion (Allium cepa) epidermal cells. Coregulation of certain NCR genes with genes coding for a potentially secreted calmodulin-like protein and for a signal peptide peptidase suggests a concerted action in nodule development. Potential functions of the NCR polypeptides in cell-to-cell signaling and creation of a defense system are discussed.
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Affiliation(s)
- Peter Mergaert
- Institut des Sciences du Végétal, Centre National de la Recherche Scientifique, Avenue de la Terrasse, 91198 Gif-sur-Yvette, France
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Nikovics K, Simidjieva J, Peres A, Ayaydin F, Pasternak T, Davies JW, Boulton MI, Dudits D, Horváth GV. Cell-cycle, phase-specific activation of Maize streak virus promoters. Mol Plant Microbe Interact 2001; 14:609-617. [PMID: 11332725 DOI: 10.1094/mpmi.2001.14.5.609] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
It is believed that geminiviral DNA replication is coupled to the cell-cycle regulatory complex of the plant cell and that the virus-early (complementary or C sense) gene products REP and REPA may be able to manipulate the regulation of the cycle. In this study, we examined expression from the promoters of Maize streak virus (MSV) in transgenic maize plants and cells to determine whether they showed cell-cycle specificity. Histochemical staining of plant roots containing "long and short" C-sense promoter sequences upstream of the GUS (beta-glucuronidase) reporter gene showed that promoter activity was restricted to the meristematic region of the roots and was enhanced by 2,4-dichlorophenoxy acetic acid (2,4-D) treatment. Analysis of reporter gene and cell-cycle-specific gene transcript levels coupled with flow cytometric data in synchronized transgenic maize cells revealed that all of the MSV promoters showed cell-cycle specificity. The coat protein gene promoter showed highest activity in early G2, whereas the C-sense promoter sequences produced two peaks of activity in the S and G2 cell-cycle phases.
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Affiliation(s)
- K Nikovics
- Institute of Plant Biology, Biological Research Centre, Hungarian Academy of Sciences, Szeged
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20
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Horváth GV, Pettkó-Szandtner A, Nikovics K, Bilgin M, Boulton M, Davies JW, Gutiérrez C, Dudits D. Prediction of functional regions of the maize streak virus replication-associated proteins by protein-protein interaction analysis. Plant Mol Biol 1998; 38:699-712. [PMID: 9862488 DOI: 10.1023/a:1006076316887] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The replication of the geminiviruses depends on the viral encoded early (complementary-sense) proteins and on host genome encoded factors. Additionally, some of the early proteins (the AL2 protein of subgroup III, and the RepA (formerly known as C1) or Rep (C1:C2) proteins of subgroup I geminiviruses) can function as transcriptional activators of virion- (V-)sense gene expression. The yeast two-hybrid system has allowed us to predict some of the functionally important regions of the maize streak virus (MSV) early proteins RepA and Rep. Defined domains of these proteins were shown to act as transactivators in yeast cells. We detected the association of the RepA and Rep proteins, and their subfragments, with the maize retinoblastoma protein (ZmRb1) which is likely to be one of the interacting host proteins. We showed the self-association capability of the MSV proteins and suggest that homo- or hetero-oligomerization may play an important role in virus replication. These results provide new insights into the role of different regions of the MSV proteins in relation to transcriptional activation and regulation of viral DNA replication.
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Affiliation(s)
- G V Horváth
- Institute of Plant Biology, Biological Research Center, Hungarian Academy of Sciences, Szeged
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