Comparative study of two Rift Valley fever virus field strains originating from Mauritania.

Rift Valley fever (RVF) is one of the major viral arthropod-borne diseases in Africa. In recent decades, RVF virus (RVFV), the causative agent of RVF, has been responsible for multiple outbreaks in West Africa with important consequences on human and animal health. In particular, an outbreak occurred in 2010 after heavy rains in the desertic region of Adrar, Mauritania.

Guidelines for In Vitro Production and Quantification of Rift Valley Fever Virus.

Rift Valley fever virus (RVFV) is an arthropod-borne virus (arbovirus) responsible for a severe zoonotic disease affecting a wide range of domestic and wild ruminants as well as humans. RVFV is endemic in many African countries and has also caused outbreaks in Madagascar and Arabian Peninsula. With regard to its wide geographical distribution, its potential to emerge in a new area, and its capability to trigger major health and economic crisis, it is essential to study and better understand several aspects of its life cycle and, in particular, its interactions with mammalian hosts and arthropod vectors.

Analysis of Negative-Strand RNA Viruses by RT-qPCR: Rift Valley Fever Virus and Toscana Virus.

RT-qPCR allows the detection of viruses and the monitoring of viral replication. This technique was extensively employed during the SARS-CoV-2 pandemic, where it demonstrated its efficiency and robustness. Here we describe the analysis of Rift Valley fever and Toscana virus infections over time, achieved through the RT-qPCR quantification of the viral genome.

IFITMs from Naturally Infected Animal Species Exhibit Distinct Restriction Capacities against Toscana and Rift Valley Fever Viruses.

Rift Valley Fever virus (RVFV) and Toscana virus (TOSV) are two pathogenic arthropod-borne viruses responsible for zoonotic infections in both humans and animals; as such, they represent a growing threat to public and veterinary health. Interferon-induced transmembrane (IFITM) proteins are broad inhibitors of a large panel of viruses belonging to various families and genera. However, little is known on the interplay between RVFV, TOSV, and the IFITM proteins derived from their naturally infected host species.

Intranasal Exposure to Rift Valley Fever Virus Live-Attenuated Strains Leads to High Mortality Rate in Immunocompetent Mice.

Rift Valley fever virus (RVFV) is a pathogenic arthropod-borne virus that can cause serious illness in both ruminants and humans. The virus can be transmitted by an arthropod bite or contact with contaminated fluids or tissues. Two live-attenuated veterinary vaccines-the Smithburn (SB) and Clone 13 (Cl.

Development of a Reverse Genetics System for Toscana Virus (Lineage A).

Toscana virus (TOSV) is a in the family, order , found in the countries surrounding the Mediterranean. TOSV is an important cause of seasonal acute meningitis and encephalitis within its range. Here, we determined the full sequence of the TOSV strain 1500590, a lineage A virus obtained from an infected patient (Marseille, 2007) and used this in combination with other sequence information to construct functional cDNA plasmids encoding the viral L, M, and S antigenomic sequences under the control of the T7 RNA promoter to recover recombinant viruses.

Remodeling of the Actin Network Associated with the Non-Structural Protein 1 (NS1) of West Nile Virus and Formation of NS1-Containing Tunneling Nanotubes.

The cellular response to the recombinant NS1 protein of West Nile virus (NS1) was studied using three different cell types: Vero E6 simian epithelial cells, SH-SY5Y human neuroblastoma cells, and U-87MG human astrocytoma cells. Cells were exposed to two different forms of NS1: (i) the exogenous secreted form, sNS1, added to the extracellular milieu; and (ii) the endogenous NS1, the intracellular form expressed in plasmid-transfected cells. The cell attachment and uptake of sNS1 varied with the cell type and were only detectable in Vero E6 and SH-SY5Y cells.

In vitro, in cellulo and structural characterizations of the interaction between the integrase of Porcine Endogenous Retrovirus A/C and proteins of the BET family.

Retroviral integrase (IN) proteins catalyze the permanent integration of the viral genome into host DNA. They can productively recruit cellular proteins, and the human Bromodomain and Extra-Terminal domain (hBET) proteins have been shown to be co-factors for integration of gamma-retroviruses such as Murine Leukemia Virus (MLV) into human cells. By using two-hybrid, co-immunoprecipitation and in vitro interaction assays, we showed that IN of the gamma- Porcine Endogenous Retrovirus-A/C (PERV IN) interacts through its C-terminal domain (CTD) with hBET proteins.

Interference with the production of infectious viral particles and bimodal inhibition of replication are broadly conserved antiviral properties of IFITMs.

IFITMs are broad antiviral factors that block incoming virions in endosomal vesicles, protecting target cells from infection. In the case of HIV-1, we and others reported the existence of an additional antiviral mechanism through which IFITMs lead to the production of virions of reduced infectivity. However, whether this second mechanism of inhibition is unique to HIV or extends to other viruses is currently unknown.

Transfer of the Cystic Fibrosis Transmembrane Conductance Regulator to Human Cystic Fibrosis Cells Mediated by Extracellular Vesicles.

Cystic fibrosis (CF) is a genetic disease caused by mutations in the CF transmembrane conductance regulator (CFTR) gene, resulting in a deficiency in chloride channel activity. In this study, extracellular vesicles (EVs), microvesicles, and exosomes were used as vehicles to deliver exogenous CFTR glycoprotein and its encoding mRNA (mRNA(GFP-CFTR)) to CF cells to correct the CFTR chloride channel function. We isolated microvesicles and exosomes from the culture medium of CFTR-positive Calu-3 cells, or from A549 cells transduced with an adenoviral vector overexpressing a GFP-tagged CFTR (GFP-CFTR).

A crystal structure of the catalytic core domain of an avian sarcoma and leukemia virus integrase suggests an alternate dimeric assembly.

Integrase (IN) is an important therapeutic target in the search for anti-Human Immunodeficiency Virus (HIV) inhibitors. This enzyme is composed of three domains and is hard to crystallize in its full form. First structural results on IN were obtained on the catalytic core domain (CCD) of the avian Rous and Sarcoma Virus strain Schmidt-Ruppin A (RSV-A) and on the CCD of HIV-1 IN.