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Kalodimou K, Stapountzi M, Vüllings N, Seib E, Klein T, Delidakis C. Separable Roles for Neur and Ubiquitin in Delta Signalling in the Drosophila CNS Lineages. Cells 2023; 12:2833. [PMID: 38132160 PMCID: PMC10741450 DOI: 10.3390/cells12242833] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Revised: 12/04/2023] [Accepted: 12/07/2023] [Indexed: 12/23/2023] Open
Abstract
The execution of a Notch signal at the plasma membrane relies on the mechanical force exerted onto Notch by its ligand. It has been appreciated that the DSL ligands need to collaborate with a ubiquitin (Ub) ligase, either Neuralized or Mindbomb1, in order to exert this pulling force, but the role of ubiquitylation per se is uncertain. Regarding the Delta-Neur pair, it is documented that neither the Neur catalytic domain nor the Delta intracellular lysines (putative Ub acceptors) are needed for activity. Here, we present a dissection of the Delta activity using the Delta-Notch-dependent expression of Hey in newborn Drosophila neurons as a sensitive in vivo assay. We show that the Delta-Neur interaction per se, rather than ubiquitylation, is needed for activity, pointing to the existence of a Delta-Neur signaling complex. The Neur catalytic domain, although not strictly needed, greatly improves Delta-Neur complex functionality when the Delta lysines are mutated, suggesting that the ubiquitylation of some component of the complex, other than Delta, can enhance signaling. Since Hey expression is sensitive to the perturbation of endocytosis, we propose that the Delta-Neur complex triggers a force-generating endocytosis event that activates Notch in the adjacent cell.
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Affiliation(s)
- Konstantina Kalodimou
- Department of Biology, University of Crete, 700 13 Heraklion, Greece;
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, 700 13 Heraklion, Greece;
| | - Margarita Stapountzi
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, 700 13 Heraklion, Greece;
| | - Nicole Vüllings
- Institute of Genetics, Heinrich-Heine-Universitaet Duesseldorf, 40225 Duesseldorf, Germany
| | - Ekaterina Seib
- Institute of Genetics, Heinrich-Heine-Universitaet Duesseldorf, 40225 Duesseldorf, Germany
| | - Thomas Klein
- Institute of Genetics, Heinrich-Heine-Universitaet Duesseldorf, 40225 Duesseldorf, Germany
| | - Christos Delidakis
- Department of Biology, University of Crete, 700 13 Heraklion, Greece;
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, 700 13 Heraklion, Greece;
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2
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High-Content RNAi Phenotypic Screening Unveils the Involvement of Human Ubiquitin-Related Enzymes in Late Cytokinesis. Cells 2022; 11:cells11233862. [PMID: 36497121 PMCID: PMC9737832 DOI: 10.3390/cells11233862] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2022] [Revised: 11/18/2022] [Accepted: 11/24/2022] [Indexed: 12/04/2022] Open
Abstract
CEP55 is a central regulator of late cytokinesis and is overexpressed in numerous cancers. Its post-translationally controlled recruitment to the midbody is crucial to the structural coordination of the abscission sequence. Our recent evidence that CEP55 contains two ubiquitin-binding domains was the first structural and functional link between ubiquitin signaling and ESCRT-mediated severing of the intercellular bridge. So far, high-content screens focusing on cytokinesis have used multinucleation as the endpoint readout. Here, we report an automated image-based detection method of intercellular bridges, which we applied to further our understanding of late cytokinetic signaling by performing an RNAi screen of ubiquitin ligases and deubiquitinases. A secondary validation confirmed four candidate genes, i.e., LNX2, NEURL, UCHL1 and RNF157, whose downregulation variably affects interconnected phenotypes related to CEP55 and its UBDs, as follows: decreased recruitment of CEP55 to the midbody, increased number of midbody remnants per cell, and increased frequency of intercellular bridges or multinucleation events. This brings into question the Notch-dependent or independent contributions of LNX2 and NEURL proteins to late cytokinesis. Similarly, the role of UCHL1 in autophagy could link its function with the fate of midbody remnants. Beyond the biological interest, this high-content screening approach could also be used to isolate anticancer drugs that act by impairing cytokinesis and CEP55 functions.
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3
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Biophysical and functional study of CRL5 Ozz, a muscle specific ubiquitin ligase complex. Sci Rep 2022; 12:7820. [PMID: 35551201 PMCID: PMC9098882 DOI: 10.1038/s41598-022-10955-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Accepted: 04/15/2022] [Indexed: 01/01/2023] Open
Abstract
Ozz, a member of the SOCS-box family of proteins, is the substrate-binding component of CRL5Ozz, a muscle-specific Cullin-RING ubiquitin ligase complex composed of Elongin B/C, Cullin 5 and Rbx1. CRL5Ozz targets for proteasomal degradation selected pools of substrates, including sarcolemma-associated β-catenin, sarcomeric MyHCemb and Alix/PDCD6IP, which all interact with the actin cytoskeleton. Ubiquitination and degradation of these substrates are required for the remodeling of the contractile sarcomeric apparatus. However, how CRL5Ozz assembles into an active E3 complex and interacts with its substrates remain unexplored. Here, we applied a baculovirus-based expression system to produce large quantities of two subcomplexes, Ozz–EloBC and Cul5–Rbx1. We show that these subcomplexes mixed in a 1:1 ratio reconstitutes a five-components CRL5Ozz monomer and dimer, but that the reconstituted complex interacts with its substrates only as monomer. The in vitro assembled CRL5Ozz complex maintains the capacity to polyubiquitinate each of its substrates, indicating that the protein production method used in these studies is well-suited to generate large amounts of a functional CRL5Ozz. Our findings highlight a mode of assembly of the CRL5Ozz that differs in presence or absence of its cognate substrates and grant further structural studies.
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Cardamone MD, Gao Y, Kwan J, Hayashi V, Sheeran M, Xu J, English J, Orofino J, Emili A, Perissi V. Neuralized-like protein 4 (NEURL4) mediates ADP-ribosylation of mitochondrial proteins. J Cell Biol 2022; 221:213006. [PMID: 35157000 PMCID: PMC8932523 DOI: 10.1083/jcb.202101021] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 09/07/2021] [Accepted: 11/04/2021] [Indexed: 12/14/2022] Open
Abstract
ADP-ribosylation is a reversible post-translational modification where an ADP-ribose moiety is covalently attached to target proteins by ADP-ribosyltransferases (ARTs). Although best known for its nuclear roles, ADP-ribosylation is increasingly recognized as a key regulatory strategy across cellular compartments. ADP-ribosylation of mitochondrial proteins has been widely reported, but the exact nature of mitochondrial ART enzymes is debated. We have identified neuralized-like protein 4 (NEURL4) as a mitochondrial ART enzyme and show that most ART activity associated with mitochondria is lost in the absence of NEURL4. The NEURL4-dependent ADP-ribosylome in mitochondrial extracts from HeLa cells includes numerous mitochondrial proteins previously shown to be ADP-ribosylated. In particular, we show that NEURL4 is required for the regulation of mtDNA integrity via poly-ADP-ribosylation of mtLIG3, the rate-limiting enzyme for base excision repair (BER). Collectively, our studies reveal that NEURL4 acts as the main mitochondrial ART enzyme under physiological conditions and provide novel insights in the regulation of mitochondria homeostasis through ADP-ribosylation.
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Affiliation(s)
| | - Yuan Gao
- Department of Biochemistry, Boston University School of Medicine, Boston, MA
| | - Julian Kwan
- Department of Biochemistry, Boston University School of Medicine, Boston, MA.,Center for Network Systems Biology, Boston University, Boston, MA
| | - Vanessa Hayashi
- Department of Biochemistry, Boston University School of Medicine, Boston, MA
| | - Megan Sheeran
- Department of Biochemistry, Boston University School of Medicine, Boston, MA
| | - Junxiang Xu
- Department of Biochemistry, Boston University School of Medicine, Boston, MA
| | - Justin English
- Department of Biochemistry, Boston University School of Medicine, Boston, MA
| | - Joseph Orofino
- Department of Biochemistry, Boston University School of Medicine, Boston, MA
| | - Andrew Emili
- Department of Biochemistry, Boston University School of Medicine, Boston, MA.,Center for Network Systems Biology, Boston University, Boston, MA
| | - Valentina Perissi
- Department of Biochemistry, Boston University School of Medicine, Boston, MA
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Diel transcriptional oscillations of light-sensitive regulatory elements in open-ocean eukaryotic plankton communities. Proc Natl Acad Sci U S A 2021; 118:2011038118. [PMID: 33547239 PMCID: PMC8017926 DOI: 10.1073/pnas.2011038118] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Most organisms coordinate key biological events to coincide with the day/night cycle. These diel oscillations are entrained through the activity of light-sensitive photoreceptors that allow organisms to respond rapidly to changes in light exposure. In the ocean, the plankton community must additionally contend with dramatic changes in the quantity and quality of light over depth. Here, we show that the predominantly blue-light field in the open-ocean environment may have driven expansion of blue light-sensitive regulatory elements in open-ocean eukaryotic plankton derived from secondary and tertiary endosymbiosis. The diel transcription of genes encoding light-sensitive elements indicate that photosynthetic and heterotrophic marine protists respond to and anticipate fluctuating light conditions in the dynamic marine environment. The 24-h cycle of light and darkness governs daily rhythms of complex behaviors across all domains of life. Intracellular photoreceptors sense specific wavelengths of light that can reset the internal circadian clock and/or elicit distinct phenotypic responses. In the surface ocean, microbial communities additionally modulate nonrhythmic changes in light quality and quantity as they are mixed to different depths. Here, we show that eukaryotic plankton in the North Pacific Subtropical Gyre transcribe genes encoding light-sensitive proteins that may serve as light-activated transcription factors, elicit light-driven electrical/chemical cascades, or initiate secondary messenger-signaling cascades. Overall, the protistan community relies on blue light-sensitive photoreceptors of the cryptochrome/photolyase family, and proteins containing the Light-Oxygen-Voltage (LOV) domain. The greatest diversification occurred within Haptophyta and photosynthetic stramenopiles where the LOV domain was combined with different DNA-binding domains and secondary signal-transduction motifs. Flagellated protists utilize green-light sensory rhodopsins and blue-light helmchromes, potentially underlying phototactic/photophobic and other behaviors toward specific wavelengths of light. Photoreceptors such as phytochromes appear to play minor roles in the North Pacific Subtropical Gyre. Transcript abundance of environmental light-sensitive protein-encoding genes that display diel patterns are found to primarily peak at dawn. The exceptions are the LOV-domain transcription factors with peaks in transcript abundances at different times and putative phototaxis photoreceptors transcribed throughout the day. Together, these data illustrate the diversity of light-sensitive proteins that may allow disparate groups of protists to respond to light and potentially synchronize patterns of growth, division, and mortality within the dynamic ocean environment.
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Abstract
ZFP57 is a master regulator of genomic imprinting. It has both maternal and zygotic functions that are partially redundant in maintaining DNA methylation at some imprinting control regions (ICRs). In this study, we found that DNA methylation was lost at most known ICRs in Zfp57 mutant embryos. Furthermore, loss of ZFP57 caused loss of parent-of-origin-dependent monoallelic expression of the target imprinted genes. The allelic expression switch occurred in the ZFP57 target imprinted genes upon loss of differential DNA methylation at the ICRs in Zfp57 mutant embryos. Specifically, upon loss of ZFP57, the alleles of the imprinted genes located on the same chromosome with the originally methylated ICR switched their expression to mimic their counterparts on the other chromosome with unmethylated ICR. Consistent with our previous study, ZFP57 could regulate the NOTCH signaling pathway in mouse embryos by impacting allelic expression of a few regulators in the NOTCH pathway. In addition, the imprinted Dlk1 gene that has been implicated in the NOTCH pathway was significantly down-regulated in Zfp57 mutant embryos. Our allelic expression switch models apply to the examined target imprinted genes controlled by either maternally or paternally methylated ICRs. Our results support the view that ZFP57 controls imprinted expression of its target imprinted genes primarily through maintaining differential DNA methylation at the ICRs.
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7
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Seib E, Klein T. The role of ligand endocytosis in notch signalling. Biol Cell 2021; 113:401-418. [PMID: 34038572 DOI: 10.1111/boc.202100009] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 05/05/2021] [Accepted: 05/17/2021] [Indexed: 12/12/2022]
Abstract
The Notch signalling receptor is a mechanoreceptor that is activated by force. This force elicits a conformational change in Notch that results in the release of its intracellular domain into the cytosol by two consecutive proteolytic cleavages. In most cases, the force is generated by pulling of the ligands on the receptor upon their endocytosis. In this review, we summarise recent work that shed a more detailed light on the role of endocytosis during ligand-dependent Notch activation and discuss the role of ubiquitylation of the ligands during this process.
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Affiliation(s)
- Ekaterina Seib
- Institute of Genetics, Heinrich-Heine-Universitaet Duesseldorf, Universitaetsstr. 1, Duesseldorf, 40225, Germany
| | - Thomas Klein
- Institute of Genetics, Heinrich-Heine-Universitaet Duesseldorf, Universitaetsstr. 1, Duesseldorf, 40225, Germany
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Lee J, Yoon K, Park P, Lee C, Kim MJ, Han DH, Kim J, Kim S, Lee H, Lee Y, Jang E, Ko H, Kong Y, Kaang B. Neur1
and
Neur2
are required for hippocampus‐dependent spatial memory and synaptic plasticity. Hippocampus 2020; 30:1158-1166. [DOI: 10.1002/hipo.23247] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2020] [Revised: 06/03/2020] [Accepted: 06/08/2020] [Indexed: 12/18/2022]
Affiliation(s)
- Jaehyun Lee
- Interdisciplinary Program in Neuroscience Seoul National University Seoul South Korea
| | - Ki‐Jun Yoon
- Department of Biological Sciences Korea Advanced Institute of Science and Technology (KAIST) Daejeon South Korea
| | - Pojeong Park
- Neurobiology Laboratory School of Biological Sciences, College of Natural Sciences, Seoul National University Seoul South Korea
| | - Chaery Lee
- Neurobiology Laboratory School of Biological Sciences, College of Natural Sciences, Seoul National University Seoul South Korea
| | - Min Jung Kim
- Interdisciplinary Program in Neuroscience Seoul National University Seoul South Korea
| | - Dae Hee Han
- Interdisciplinary Program in Neuroscience Seoul National University Seoul South Korea
| | - Ji‐il Kim
- Neurobiology Laboratory School of Biological Sciences, College of Natural Sciences, Seoul National University Seoul South Korea
| | - Somi Kim
- Neurobiology Laboratory School of Biological Sciences, College of Natural Sciences, Seoul National University Seoul South Korea
| | - Hye‐Ryeon Lee
- Neurobiology Laboratory School of Biological Sciences, College of Natural Sciences, Seoul National University Seoul South Korea
| | - Yeseul Lee
- Neurobiology Laboratory School of Biological Sciences, College of Natural Sciences, Seoul National University Seoul South Korea
| | - Eun‐Hae Jang
- Neurobiology Laboratory School of Biological Sciences, College of Natural Sciences, Seoul National University Seoul South Korea
| | - Hyoung‐Gon Ko
- Department of Anatomy and Neurobiology School of Dentistry, Kyungpook National University Daegu South Korea
| | - Young‐Yun Kong
- School of Biological Sciences, College of Natural Sciences Seoul National University Seoul South Korea
| | - Bong‐Kiun Kaang
- Interdisciplinary Program in Neuroscience Seoul National University Seoul South Korea
- Neurobiology Laboratory School of Biological Sciences, College of Natural Sciences, Seoul National University Seoul South Korea
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9
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Neuralized E3 Ubiquitin Protein Ligase 3 Is an Inducible Antiviral Effector That Inhibits Hepatitis C Virus Assembly by Targeting Viral E1 Glycoprotein. J Virol 2018; 92:JVI.01123-18. [PMID: 30111563 DOI: 10.1128/jvi.01123-18] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Accepted: 08/08/2018] [Indexed: 12/14/2022] Open
Abstract
Hepatitis C virus (HCV) infection is a major cause of chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma. HCV can be sensed by host innate immunity to induce expression of interferons (IFNs) and a number of antiviral effectors. In this study, we found HCV infection induced the expression of neuralized E3 ubiquitin protein ligase 3 (NEURL3), a putative E3 ligase, in a manner that requires the involvement of innate immune sensing but is independent of the IFN action. Furthermore, we showed that NEURL3 inhibited HCV infection while it had little effect on other RNA viruses, including Zika virus (ZIKV), dengue virus (DENV), and vesicular stomatitis virus (VSV). Mechanistic studies demonstrated that NEURL3 inhibited HCV assembly by directly binding HCV envelope glycoprotein E1 to interfere with the E1/E2 heterodimerization, an important prerequisite for virion morphogenesis. Finally, we showed that knockout of NEURL3 significantly enhanced HCV infection. In summary, we identified NEURL3 as a novel inducible antiviral host factor that suppresses HCV assembly. Our results not only shed new insight into how host innate immunity acts against HCV but also revealed a new important biological function for NEURL3.IMPORTANCE The exact biological function of NEURL3, a putative E3 ligase, remains largely unknown. In this study, we found that NEURL3 could be upregulated upon HCV infection in a manner dependent on pattern recognition receptor-mediated innate immune response. NEURL3 inhibits HCV assembly by directly binding viral E1 envelope glycoprotein to disrupt its interaction with E2, an action that requires its Neuralized homology repeat (NHR) domain but not the RING domain. Furthermore, we found that NEURL3 has a pangenotypic anti-HCV activity and interacts with E1 of genotypes 2a, 1b, 3a, and 6a but does not inhibit other closely related RNA viruses, such as ZIKV, DENV, and VSV. To our knowledge, our study is the first report to demonstrate that NEURL3 functions as an antiviral host factor. Our results not only shed new insight into how host innate immunity acts against HCV, but also revealed a new important biological function for NEURL3.
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10
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Secco I, Barile L, Torrini C, Zentilin L, Vassalli G, Giacca M, Collesi C. Notch pathway activation enhances cardiosphere in vitro expansion. J Cell Mol Med 2018; 22:5583-5595. [PMID: 30138533 PMCID: PMC6201224 DOI: 10.1111/jcmm.13832] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Revised: 06/08/2018] [Accepted: 06/30/2018] [Indexed: 11/26/2022] Open
Abstract
Cardiospheres (CSps) are self‐assembling clusters of a heterogeneous population of poorly differentiated cells outgrowing from in vitro cultured cardiac explants. Scanty information is available on the molecular pathways regulating CSp growth and their differentiation potential towards cardiac and vascular lineages. Here we report that Notch1 stimulates a massive increase in both CSp number and size, inducing a peculiar gene expression programme leading to a cardiovascular molecular signature. These effects were further enhanced using Adeno‐Associated Virus (AAV)‐based gene transfer of activated Notch1‐intracellular domain (N1‐ICD) or soluble‐Jagged1 (sJ1) ligand to CSp‐forming cells. A peculiar effect was exploited by selected pro‐proliferating miRNAs: hsa‐miR‐590‐3p induced a cardiovascular gene expression programme, while hsa‐miR‐199a‐3p acted as the most potent stimulus for the activation of the Notch pathway, thus showing that, unlike in adult cardiomyocytes, these miRNAs involve Notch signalling activation in CSps. Our results identify Notch1 as a crucial regulator of CSp growth and differentiation along the vascular lineage, raising the attracting possibility that forced activation of this pathway might be exploited to promote in vitro CSp expansion as a tool for toxicology screening and cell‐free therapeutic strategies.
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Affiliation(s)
- Ilaria Secco
- Molecular Medicine Laboratory, International Centre for Genetic Engineering and Biotechnology (ICGEB), Trieste, Italy
| | - Lucio Barile
- Fondazione Cardiocentro Ticino and Swiss Institute for Regenerative Medicine, Lugano, Switzerland
| | - Consuelo Torrini
- Molecular Medicine Laboratory, International Centre for Genetic Engineering and Biotechnology (ICGEB), Trieste, Italy
| | - Lorena Zentilin
- Molecular Medicine Laboratory, International Centre for Genetic Engineering and Biotechnology (ICGEB), Trieste, Italy
| | - Giuseppe Vassalli
- Fondazione Cardiocentro Ticino and Swiss Institute for Regenerative Medicine, Lugano, Switzerland
| | - Mauro Giacca
- Molecular Medicine Laboratory, International Centre for Genetic Engineering and Biotechnology (ICGEB), Trieste, Italy.,Department of Medical, Surgical and Health Sciences, University of Trieste, Trieste, Italy
| | - Chiara Collesi
- Molecular Medicine Laboratory, International Centre for Genetic Engineering and Biotechnology (ICGEB), Trieste, Italy.,Department of Medical, Surgical and Health Sciences, University of Trieste, Trieste, Italy
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