scholarly journals Twelfth International Foamy Virus Conference—Meeting Report

Viruses ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 134 ◽  
Author(s):  
Ottmar Herchenröder ◽  
Martin Löchelt ◽  
Florence Buseyne ◽  
Antoine Gessain ◽  
Marcelo A. Soares ◽  
...  
Keyword(s):  
Viral Vectors ◽  
Foamy Virus ◽  
Meeting Report ◽  
Virus Structure ◽  
Host Interactions ◽  
Research Areas ◽  
Current State ◽  
Foamy Viruses ◽  
Viral Host Interactions ◽  
Human Primate

The 12th International Foamy Virus Conference took place on August 30–31, 2018 at the Technische Universität Dresden, Dresden, Germany. The meeting included presentations on current research on non-human primate and non-primate foamy viruses (FVs; also called spumaretroviruses) as well as keynote talks on related research areas in retroviruses. The taxonomy of foamy viruses was updated earlier this year to create five new genera in the subfamily, Spumaretrovirinae, based on their animal hosts. Research on viruses from different genera was presented on topics of potential relevance to human health, such as natural infections and cross-species transmission, replication, and viral-host interactions in particular with the immune system, dual retrovirus infections, virus structure and biology, and viral vectors for gene therapy. This article provides an overview of the current state-of-the-field, summarizes the meeting highlights, and presents some important questions that need to be addressed in the future.

scholarly journals Feline foamy virus Tas protein is a DNA-binding transactivator

2004 ◽  
Vol 85 (10) ◽  
pp. 2931-2935 ◽  
Author(s):  
Shinya Omoto ◽  
Ebiamadon Andi Brisibe ◽  
Harumi Okuyama ◽  
Yoichi R. Fujii
Keyword(s):  
Dna Binding ◽  
Foamy Virus ◽  
Envelope Gene ◽  
Promoter Regions ◽  
Immunodeficiency Virus ◽  
Foamy Viruses ◽  
Sequence Position ◽  
Activate Gene ◽  
Human Primate

Foamy viruses (FVs) harbour a transcriptional transactivator (Tas) and two Tas-responsive promoter regions, one in the 5′ long terminal repeat (LTR) and the other an internal promoter (IP) in the envelope gene. To analyse the mechanism of transactivation of the FVs, the specificity of feline FV (FFV) Tas protein, which is more distantly related to the respective proteins of non-human primate origin, were investigated. FFV Tas has been shown specifically to activate gene expression from the cognate promoters. No cross-transactivation was noted of the prototype foamy virus and human immunodeficiency virus type 1 LTR. The putative transactivation response element of FFV Tas was mapped to the 5′ LTR U3 region (approximately nt −228 to −195). FFV Tas binds to this element in addition to a previously described sequence (position −66 to −51). It is therefore concluded that FFV Tas is a DNA-binding transactivator that interacts with at least two regions in the virus LTR.

scholarly journals A Systematic Survey of ML Datasets for Prime CV Research Areas—Media and Metadata

Data ◽  
2021 ◽  
Vol 6 (2) ◽  
pp. 12
Author(s):  
Helder F. Castro ◽  
Jaime S. Cardoso ◽  
Maria T. Andrade
Keyword(s):  
Machine Learning ◽  
Computer Vision ◽  
Qualitative Analysis ◽  
Continuous Growth ◽  
Scientific Databases ◽  
Extensive Survey ◽  
Research Areas ◽  
Current State ◽  
Global View ◽  
Cooperative Production

The ever-growing capabilities of computers have enabled pursuing Computer Vision through Machine Learning (i.e., MLCV). ML tools require large amounts of information to learn from (ML datasets). These are costly to produce but have received reduced attention regarding standardization. This prevents the cooperative production and exploitation of these resources, impedes countless synergies, and hinders ML research. No global view exists of the MLCV dataset tissue. Acquiring it is fundamental to enable standardization. We provide an extensive survey of the evolution and current state of MLCV datasets (1994 to 2019) for a set of specific CV areas as well as a quantitative and qualitative analysis of the results. Data were gathered from online scientific databases (e.g., Google Scholar, CiteSeerX). We reveal the heterogeneous plethora that comprises the MLCV dataset tissue; their continuous growth in volume and complexity; the specificities of the evolution of their media and metadata components regarding a range of aspects; and that MLCV progress requires the construction of a global standardized (structuring, manipulating, and sharing) MLCV “library”. Accordingly, we formulate a novel interpretation of this dataset collective as a global tissue of synthetic cognitive visual memories and define the immediately necessary steps to advance its standardization and integration.

scholarly journals Chikungunya and Zika Viruses: Co-Circulation and the Interplay between Viral Proteins and Host Factors

Pathogens ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 448
Author(s):  
Sineewanlaya Wichit ◽  
Nuttamonpat Gumpangseth ◽  
Rodolphe Hamel ◽  
Sakda Yainoy ◽  
Siwaret Arikit ◽  
...  
Keyword(s):  
Antiviral Drug ◽  
Virus Transmission ◽  
Antiviral Agent ◽  
Viral Proteins ◽  
Targeted Therapeutics ◽  
Limited Information ◽  
Mosquito Vectors ◽  
Host Proteins ◽  
Host Interactions ◽  
Viral Host Interactions

Chikungunya and Zika viruses, both transmitted by mosquito vectors, have globally re-emerged over for the last 60 years and resulted in crucial social and economic concerns. Presently, there is no specific antiviral agent or vaccine against these debilitating viruses. Understanding viral–host interactions is needed to develop targeted therapeutics. However, there is presently limited information in this area. In this review, we start with the updated virology and replication cycle of each virus. Transmission by similar mosquito vectors, frequent co-circulation, and occurrence of co-infection are summarized. Finally, the targeted host proteins/factors used by the viruses are discussed. There is an urgent need to better understand the virus–host interactions that will facilitate antiviral drug development and thus reduce the global burden of infections caused by arboviruses.

Image-Guided Intratumoral Delivery of Immunotherapeutics in Gastrointestinal Malignancies

2021 ◽  
Author(s):  
Yang Qiao ◽  
Rahul A. Sheth ◽  
Alda Tam
Keyword(s):  
Viral Vectors ◽  
Adaptive Immune System ◽  
Clinical Development ◽  
Gastrointestinal Malignancies ◽  
Robust Immune Response ◽  
Image Guided ◽  
Current State ◽  
Specific Antigens ◽  
Promising Treatment ◽  
Intratumoral Delivery

AbstractIntratumoral (IT) administration of immunotherapy is a promising treatment strategy under clinical development for gastrointestinal malignancies. Due to its targeted nature, IT immunotherapies can generate regional proinflammatory microenvironments that result in the focal recruitment of tumor-specific immune cells. Precision targeting of tumors via IT immunotherapy injection theoretically produces a more robust immune response to the treated tumor itself and to distant metastatic tumors that share tumor-specific antigens with those of the treated tumor, while also minimizing the priming of the adaptive immune system to nonspecific antigens. Diverse arrays of IT immunotherapeutic agents including but not limited to lyophilized bacteria, viral vectors, cellular-based agents, molecules, and peptides, both as monotherapies and in combination with systemic immunotherapies, are in various stages of preclinical and clinical development. In this review, we summarize the current state of the art for IT immunotherapy and highlight potential future directions and their relevance to image-guided interventionalists.

scholarly journals Generation of an improved foamy virus vector by dissection of cis-acting sequences

2009 ◽  
Vol 90 (2) ◽  
pp. 481-487 ◽  
Author(s):  
Tatiana Wiktorowicz ◽  
Katrin Peters ◽  
Nicole Armbruster ◽  
Andre F. Steinert ◽  
Axel Rethwilm
Keyword(s):  
Foamy Virus ◽  
Human Mesenchymal Stem Cells ◽  
Viral Capsid ◽  
Rna Packaging ◽  
Gag Protein ◽  
Protein Precursor ◽  
Cis Acting ◽  
Foamy Viruses ◽  
Protein Incorporation ◽  
Primary Human Cells

In contrast to other retroviruses, foamy viruses (FVs) generate their Pol protein precursor independently of the Gag protein from a spliced mRNA. The exact mechanism of Pol protein incorporation into the viral capsid is poorly understood. Previously, we showed that Pol encapsidation critically depends on the packaging of (pre-) genomic RNA and identified two distinct signals within the cis-acting sequences (CASI and CASII), Pol encapsidation sequences (PESI and PESII), which are required for Pol capsid incorporation. Here, we investigated whether the presence of PESI and PESII in an FV vector is sufficient for Pol encapsidation and whether the rather extended CASII element can be shortened without loss of functionality. Our results indicate that (i) the presence of PESI and II are not sufficient for Pol encapsidation, (ii) prototype FV vectors with a shortened CASII element retain Pol incorporation and full functionality, in particular upon transducing fibroblasts and primary human mesenchymal stem cells, (iii) the presence of the central poly purine tract significantly increased the transduction rates of FV vectors and (iv) Pol encapsidation and RNA packaging can be clearly separated. In essence, we designed a new FV vector that bears approximately 850 bp less of CAS than previously established vectors and is fully functional when analysed to transduce cell lines and primary human cells.

Plasmodium knowlesi: a relevant, versatile experimental malaria model

Parasitology ◽  
2016 ◽  
Vol 145 (1) ◽  
pp. 56-70 ◽  
Author(s):  
ERICA M. PASINI ◽  
ANNE-MARIE ZEEMAN ◽  
ANNEMARIE VOORBERG-VAN DER WEL ◽  
CLEMENS H. M. KOCKEN
Keyword(s):  
Parasite Species ◽  
Vaccine Development ◽  
Plasmodium Knowlesi ◽  
Host Interactions ◽  
Model Studies ◽  
Human Red Blood Cells ◽  
Malaria Model ◽  
Human Primate

SUMMARYThe primate malariaPlasmodium knowlesihas a long-standing history as an experimental malaria model. Studies using this model parasite in combination with its various natural and experimental non-human primate hosts have led to important advances in vaccine development and in our understanding of malaria invasion, immunology and parasite–host interactions. The adaptation to long-termin vitrocontinuous blood stage culture in rhesus monkey,Macaca fascicularisand human red blood cells, as well as the development of various transfection methodologies has resulted in a highly versatile experimental malaria model, further increasing the potential of what was already a very powerful model. The growing evidence thatP. knowlesiis an important human zoonosis in South-East Asia has added relevance to former and future studies of this parasite species.

scholarly journals Foamy Virus Vector Carries a Strong Insulator in Its Long Terminal Repeat Which Reduces Its Genotoxic Potential

2017 ◽  
Vol 92 (1) ◽  
Author(s):  
Michael Aaron Goodman ◽  
Paritha Arumugam ◽  
Devin Marie Pillis ◽  
Anastacia Loberg ◽  
Mohammed Nasimuzzaman ◽  
...  
Keyword(s):  
Gene Therapy ◽  
Long Terminal Repeat ◽  
Transgene Expression ◽  
Viral Vectors ◽  
Foamy Virus ◽  
Terminal Repeat ◽  
Genotoxic Potential ◽  
Binding Factor ◽  
Activation Assay ◽  
Lentivirus Vectors

ABSTRACTStrong viral enhancers in gammaretrovirus vectors have caused cellular proto-oncogene activation and leukemia, necessitating the use of cellular promoters in “enhancerless” self-inactivating integrating vectors. However, cellular promoters result in relatively low transgene expression, often leading to inadequate disease phenotype correction. Vectors derived from foamy virus, a nonpathogenic retrovirus, show higher preference for nongenic integrations than gammaretroviruses/lentiviruses and preferential integration near transcriptional start sites, like gammaretroviruses. We found that strong viral enhancers/promoters placed in foamy viral vectors caused extremely low immortalization of primary mouse hematopoietic stem/progenitor cells compared to analogous gammaretrovirus/lentivirus vectors carrying the same enhancers/promoters, an effect not explained solely by foamy virus' modest insertional site preference for nongenic regions compared to gammaretrovirus/lentivirus vectors. Using CRISPR/Cas9-mediated targeted insertion of analogous proviral sequences into theLMO2gene and then measuringLMO2expression, we demonstrate a sequence-specific effect of foamy virus, independent of insertional bias, contributing to reduced genotoxicity. We show that this effect is mediated by a 36-bp insulator located in the foamy virus long terminal repeat (LTR) that has high-affinity binding to the CCCTC-binding factor. Using our LMO2 activation assay,LMO2expression was significantly increased when this insulator was removed from foamy virus and significantly reduced when the insulator was inserted into the lentiviral LTR. Our results elucidate a mechanism underlying the low genotoxicity of foamy virus, identify a novel insulator, and support the use of foamy virus as a vector for gene therapy, especially when strong enhancers/promoters are required.IMPORTANCEUnderstanding the genotoxic potential of viral vectors is important in designing safe and efficacious vectors for gene therapy. Self-inactivating vectors devoid of viral long-terminal-repeat enhancers have proven safe; however, transgene expression from cellular promoters is often insufficient for full phenotypic correction. Foamy virus is an attractive vector for gene therapy. We found foamy virus vectors to be remarkably less genotoxic, well below what was expected from their integration site preferences. We demonstrate that the foamy virus long terminal repeats contain an insulator element that binds CCCTC-binding factor and reduces its insertional genotoxicity. Our study elucidates a mechanism behind the low genotoxic potential of foamy virus, identifies a unique insulator, and supports the use of foamy virus as a vector for gene therapy.

scholarly journals RNA and Protein Requirements for Incorporation of the Pol Protein into Foamy Virus Particles

2005 ◽  
Vol 79 (11) ◽  
pp. 7005-7013 ◽  
Author(s):  
Katrin Peters ◽  
Tatiana Wiktorowicz ◽  
Martin Heinkelein ◽  
Axel Rethwilm
Keyword(s):  
Foamy Virus ◽  
Genomic Rna ◽  
Rna Packaging ◽  
Gag Protein ◽  
Protein Precursor ◽  
Protein Requirements ◽  
Virus Particles ◽  
Foamy Viruses ◽  
Protein Incorporation ◽  
The Individual

ABSTRACT Foamy viruses (FVs) generate their Pol protein precursor molecule independently of the Gag protein from a spliced mRNA. This mode of expression raises the question of the mechanism of Pol protein incorporation into the viral particle (capsid). We previously showed that the packaging of (pre)genomic RNA is essential for Pol encapsidation (M. Heinkelein, C. Leurs, M. Rammling, K. Peters, H. Hanenberg, and A. Rethwilm, J. Virol. 76:10069-10073, 2002). Here, we demonstrate that distinct sequences in the RNA, which we termed Pol encapsidation sequences (PES), are required to incorporate Pol protein into the FV capsid. Two PES were found, which are contained in the previously identified cis-acting sequences necessary to transfer an FV vector. One PES is located in the U5 region of the 5′ long terminal repeat and one at the 3′ end of the pol gene region. Neither element has any significant effect on RNA packaging. However, deletion of either PES resulted in a significant reduction in Pol encapsidation. On the protein level, we show that only the Pol precursor, but not the individual reverse transcriptase (RT) and integrase (IN) subunits, is incorporated into FV particles. However, enzymatic activities of the protease (PR), RT, or IN are not required. Our results strengthen the view that in FVs, (pre)genomic RNA functions as a bridging molecule between Gag and Pol precursor proteins.

scholarly journals Foamy Virus Integration

2004 ◽  
Vol 78 (5) ◽  
pp. 2472-2477 ◽  
Author(s):  
Thomas Juretzek ◽  
Teresa Holm ◽  
Kathleen Gärtner ◽  
Sylvia Kanzler ◽  
Dirk Lindemann ◽  
...  
Keyword(s):  
Infectious Virus ◽  
High Titer ◽  
Foamy Virus ◽  
Wild Type ◽  
Foamy Viruses ◽  
Unintegrated Dna ◽  
Particle Export ◽  
The Right ◽  
Virus Integration ◽  
Transcription And Replication

ABSTRACT It had been suggested that during integration of spumaretroviruses (foamy viruses) the right (U5) end of the cDNA is processed, while the left (U3) remains uncleaved. We confirmed this hypothesis by sequencing two-long terminal repeat (LTR) circle junctions of unintegrated DNA. Based on an infectious foamy virus molecular clone, a set of constructs harboring mutations at the 5′ end of the U3 region in the 3′ LTR was analyzed for particle export, reverse transcription, and replication. Following transient transfection some mutants were severely impaired in generating infectious virus, while others replicated almost like the wild type. The replication competence of the mutants was unrelated to the cleavability of the newly created U3 end. This became obvious with two mutants both belonging to the high-titer type. One mutant containing a dinucleotide artificially transferred from the right to the left end was trimmed upon integration, while another one with an unrelated dinucleotide in that place was not. The latter construct in particular showed that the canonical TG motif at the beginning of the provirus is not essential for foamy virus integration.

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