Long noncoding RNAs (lncRNAs) are increasingly appreciated as regulators of cell-specific gene expression. Here, an enhancer-like lncRNA termed NeST (Nettoie Salmonella pas Theiler’s; cleanup Salmonella not Theiler’s) is shown to be causal for all phenotypes conferred by murine viral susceptibility locus Tmevp3. This locus was defined by crosses between SJL/J and B10.S mice and contains several candidate genes, including NeST. The SJL/J-derived locus confers higher lncRNA expression, increased interferon-γ abundance in activated CD8+ T cells, increased Theiler’s virus persistence and decreased Salmonella enterica pathogenesis. Transgenic expression of NeST lncRNA alone was sufficient to confer all phenotypes of the SJL/J locus. NeST RNA was found to bind WDR5, a component of the histone H3 lysine 4 methytransferase complex, and to alter histone 3 methylation at the interferon gamma locus. Thus, this lncRNA regulates epigenetic marking of IFNγ-encoding chromatin, expression of IFN-γ and susceptibility to a viral and a bacterial pathogen.

Objective The lesions of Parkinson's disease spread through the brain in a characteristic pattern that corresponds to axonal projections. Previous observations suggest that misfolded α-synuclein could behave as a prion, moving from neuron to neuron and causing endogenous α-synuclein to misfold. Here, we characterized and quantified the axonal transport of α-synuclein fibrils and showed that fibrils could be transferred from axons to second-order neurons following anterograde transport. Methods We grew primary cortical mouse neurons in microfluidic devices to separate soma from axonal projections in fluidically isolated microenvironments. We used live-cell imaging and immunofluorescence to characterize the transport of fluorescent α-synuclein fibrils and their transfer to second-order neurons. Results Fibrillar α-synuclein was internalized by primary neurons and transported in axons with kinetics consistent with slow component-b of axonal transport (fast axonal transport with saltatory movement). Fibrillar α-synuclein was readily observed in the cell bodies of second-order neurons following anterograde axonal transport. Axon-to-soma transfer appeared not to require synaptic contacts. Interpretation These results support the hypothesis that the progression of Parkinson's disease can be caused by neuron-to-neuron spread of α-synuclein aggregates and that the anatomical pattern of progression of lesions between axonally connected areas results from the axonal transport of such aggregates. That the transfer did not appear to be transsynaptic gives hope that α-synuclein fibrils could be intercepted by drugs during the extra-cellular phase of their journey.

Live attenuated RNA viruses make highly efficient vaccines. Among them, measles virus (MV) vaccine has been given to a very large number of children and has been shown to be highly efficacious and safe. Therefore, this vaccine might be a very promising vector to immunize children against both measles and other infectious agents, such as human immunodeficiency virus. A vector was previously derived from the Edmonston B strain of MV, a vaccine strain abandoned 25 years ago. Sequence analysis revealed that the genome of this vector diverges from Edmonston B by 10 amino acid substitutions not related to any Edmonston subgroup. Here we describe an infectious cDNA for the Schwarz/Moraten strain, a widely used MV vaccine. This cDNA was constructed from a batch of commercial vaccine. The extremities of the cDNA were engineered in order to maximize virus yield during rescue. A previously described helper cell-based rescue system was adapted by cocultivating transfected cells on primary chicken embryo fibroblasts, the cells used to produce the Schwarz/ Moraten vaccine. After two passages the sequence of the rescued virus was identical to that of the cDNA and of the published Schwarz/Moraten sequence. Two additional transcription units were introduced in the cDNA for cloning foreign genetic material. The immunogenicity of rescued virus was studied in macaques and in mice transgenic for the CD46 MV receptor. Antibody titers and T-cell responses (ELISpot) in animals inoculated with low doses of rescued virus were identical to those obtained with commercial Schwarz MV vaccine. In contrast, the immunogenicity of the previously described Edmonston B strain-derived MV clone was much lower. This new molecular clone will allow for the production of MV vaccine without having to rely on seed stocks. The additional transcription units allow expressing heterologous antigens, thereby providing polyvalent vaccines based on an approved, safe, and efficient MV vaccine strain that is used worldwide.

The Tmevp3 locus controls the load of Theiler's virus RNA during persistent infection of the mouse central nervous system (CNS). We identified a candidate gene at this locus, Tmevpg1, by using a positional cloning approach. Tmevpg1 and its human ortholog, TMEVPG1, are expressed in the immune system and encode what appears to be a noncoding RNA. They are located in a cluster of cytokine genes that includes the genes for gamma interferon and one or two homolog of interleukin-10. We now report that Tmevpg1 is expressed in CNS-infiltrating immune cells of resistant B10.S mice, but not in those of susceptible SJL/J mice, following inoculation with Theiler's virus. The pattern of expression of Tmevpg1 is the same in B10.S mice and in SJL/J mice congenic for the resistant B10.S haplotype of Tmevp3. Nineteen polymorphisms were identified when the Tmevpg1 genes of B10.S and SJL/J mice were compared. Interestingly, Tmevpg1 is down regulated after in vitro stimulation of murine CD4 ؉ or CD8 ؉ splenocytes, whereas Ifng is up regulated. Similar patterns of expression of TMEVPG1 and IFNG were observed in human NK cells and CD4 ؉ and CD8 ؉ T lymphocytes. Therefore, Tmevpg1 is a strong candidate gene for the Tmevp3 locus and may be involved in the control of Ifng gene expression.After intracranial inoculation, the DA strain of Theiler's virus replicates for approximately 2 weeks in neurons of the mouse brain and spinal cord, regardless of the mouse's genetic background. Some genetically resistant mice clear the infection at this stage. Others, which are susceptible to persistence of the infection, remain infected for life (26). However, in this case, the virus does not persist in neurons. Instead, it is found in glial cells of the white matter of the spinal cord. Persistent infection of the white matter induces chronic inflammation and primary demyelination similar to those seen in multiple sclerosis (25). Susceptibility to viral persistence varies greatly among inbred strains of mice. The viral genome load during persistent infection is controlled mainly by the H2D class I gene (4-6, 24). However, the SJL/J strain is the only inbred strain among 16 examined for which the viral genome load is greater than that predicted by its H2 s haplotype (13). Studies of bone marrow chimeras of the SJL/J and B10.S strains, which both bear an H2 s haplotype, showed that susceptibility loci with major effects on persistence are expressed in cells of the immune system (3). Some non-H2 susceptibility loci were mapped by using a backcross and congenic mice between the SJL/J and B10.S strains. Two susceptibility loci, Tmevp2 and Tmevp3, were located on chromosome 10 close to the Ifng locus (8, 12). However, immunological studies indicated that the Ifng gene does not explain the effects of the Tmevp2 or the Tmevp3 locus (30). Instead, the Tmevpg1 gene was recently identified by positional cloning of the Tmevp3 locus. It is located telomeric to a cluster of cytokines, which includes the Ifng and IL-22/Il-Tif genes (36). Tmevpg1 has six exons and ap...

Theiler's virus causes a persistent and demyelinating infection of the central nervous system of the mouse, which is one of the best animal models to study multiple sclerosis. This review focuses on the mechanism of persistence. The virus infects neurons for a few weeks and then shifts to white matter, where it persists in glial cells and macrophages. Oligodendrocytes are crucial host cells, as shown by the resistance to persistent infection of mice bearing myelin mutations. Two viral proteins, L and L*, contribute to persistence by interfering with host defenses. L, a small zinc-finger protein, restricts the production of interferon. L*, a unique example of a picornaviral protein translated from an overlapping open reading frame, facilitates the infection of macrophages. Susceptibility to persistent infection, which varies among inbred mouse strains, is multigenic. H2 class I genes have a major effect on susceptibility. Among several non-H2 susceptibility loci, Tmevp3 appears to regulate the expression of important cytokines.