Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Borna disease virus”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources

Identification of alternative splicing and negative splicing activity of a nonsegmented negative-strand RNA virus, Borna disease virus.

Borna disease virus (BDV) is a nonsegmented negative-strand RNA virus that belongs to the Mononegavirales. Unlike other animal viruses of this order, BDV replicates and transcribes in the nucleus of infected cells. Previous studies have shown that BDV uses RNA splicing machinery for its mRNA expression. In the present study, we identified spliced RNAs that use an alternative 3' splice site, SA3, in BDV-infected cell lines as well as infected animal brain cells. Transient transfection analysis of cDNA clones of BDV RNA revealed that although SA3 is a favorable splice site in mammalian cells, utilization of SA3 is negatively regulated in infected cells. This negative splicing activity of the SA3 site is regulated by a putative cis-acting region, the exon splicing suppressor (ESS), within the polymerase exon of BDV. The BDV ESS contains similar motifs to other known ESSs present in viral and cellular genes. Furthermore, our results indicated that a functional polyadenylation signal just upstream of the BDV ESS is also involved in the regulation of alternative splicing of BDV. These observations represent the first documentation of complex RNA splicing in animal RNA viruses and also provide new insight into the mechanism of regulation of alternative splicing in animal viruses.

Alternative Splicing↗

Genomic organization of Borna disease virus.

Borna disease virus is a neurotropic negative-strand RNA virus that infects a wide range of vertebrate hosts, causing disturbances in movement and behavior. We have cloned and sequenced the 8910-nucleotide viral genome by using RNA from Borna disease virus particles. The viral genome has complementary 3' and 5' termini and contains antisense information for five open reading frames. Homology to Filoviridae, Paramyxoviridae, and Rhabdoviridae is found in both cistronic and extracistronic regions. Northern analysis indicates that the virus transcribes mono- and polycistronic RNAs and uses termination/polyadenylylation signals reminiscent of those observed in other negative-strand RNA viruses. Borna disease virus is likely to represent a previously unrecognized genus, bornaviruses, or family, Bornaviridae, within the order Mononegavirales.

Amino Acid Sequence↗

[The development of a purification method for Borna disease virus].

Borna disease virus represents an unknown neurotropic agent. It causes encephalitis in horses and sheep. The same or a similar type of virus might be responsible for psychiatric disorders in man. So far, it has been impossible to purify this agent to such an extent that it could be analyzed biochemically or electronmicroscopically. Therefore, different conventional virus purification techniques are applied in order to develop a method for obtaining purified Borna disease virus from infectious rat brain or persistently infected cell culture material.

Animals↗

Borna disease virus.

Borna disease virus, a negative-strand RNA virus, infects a wide variety of warm-blooded animals. Depending on the age of the host and the integrity of its immune response, infection may be asymptomatic or cause a broad spectrum of behavioral disorders. Unusual features of Borna disease virus biology include nuclear localization of replication and transcription; diverse strategies for regulation of gene expression; and interaction with signaling pathways resulting in subtle neuropathology. Although the question of human infection remains unresolved, burgeoning interest in this unique pathogen has provided tools for exploring the pharmacology and neurochemistry of neuropsychiatric disorders potentially linked to infection. Analysis of rodent models of infection has yielded insights into mechanisms by which neurotropic agents and/or immune factors may impact developing or mature central nervous system circuitry to effect complex disturbances in movement and behavior.

Animals↗

Induction of protection against Borna disease by inoculation with high-dose-attenuated Borna disease virus.

Borna disease is a chronic neurological disease caused by an enveloped negative-strand RNA virus (BDV). Experimental disease can be reproduced in rats with brain homogenates derived from infected animals or with virus derived from infected cells in culture. The virus replicates in cultured cells without evidence of cytopathic effect or production of significant levels of cell-free virus. Borna disease is caused by an immunopathological response to viral infection of neural cells. To further investigate the pathogenesis of Borna disease, rats were inoculated with different doses of BDV attenuated by culture in MDCK cells. Low doses of attenuated BDV (10(2)-10(4) TCID50) resulted in typical clinical disease and severe encephalitis; however, the lag period between inoculation and disease was considerably longer than that with virulent BDV. In contrast, animals inoculated with a high dose of attenuated BDV (10(5)-10(6) TCID50) did not develop clinical disease, although a mild encephalitic response was present that did not progress beyond the mild encephalitis. Animals inoculated with a high dose of BDV developed high titers of anti-BDV antibody and were protected against virulent challenge. Protection was correlated with the rapid induction of an immune response in the animals and the lack of any biologically detectable virus in the CNS.

Animals↗

Clinical similarities and close genetic relationship of human and animal Borna disease virus.

Borna disease virus (BDV) is the prototype genus of a new family, Bornaviridae, within the order Mononegavirales. BDV naturally infects animals and man. The symptomatology in animals ranges from subclinical infection to rare cases of encephalitis. Asymptomatic infection seemed more frequent than expected, based on antibody data from 100 healthy horses derived from different stables with a history of diseased cases (30-40% carriers). Likewise, phasic episodes of a neurobehavioral syndrome followed by recovery were much more common than fatal neurologic disease. They were paralleled by expression of BDV antigens (N-protein p40, P-protein p24) and RNA transcripts in peripheral blood mononuclear cells, indicating viral activation. Representative longitudinal studies showed that episodes of depressive illness in humans as well as apathetic phases in infected horses were accompanied by antigen expression and followed a similar clinical course. After recovery, BDV antigen disappeared. This temporal congruence, together with the recent isolation of infectious BDV from such patients, points to a contributory role of this virus in human affective disorders. Successful amelioration of BDV-induced neurobehavioral disease in horses with antidepressants applied in psychiatry, supported a common viral pathomechanism, involving reversible disturbances of the neurotransmitter network in the limbic system. Sequences of genetic material amplified from infected animal tissue and human PBMCs revealed a close interspecies relationship and high sequence conservation of the BDV genome. In human BDV isolates, however, single unique mutations were prominent in four genes. This finding supports the hypothesis that despite of high genomic conservation, species-specific genotypes may be definable, provided the sequences are derived from RNA of infectious virus.

Aged↗

Borna disease virus.

Borna disease virus (BDV) is unique amongst animal RNA viruses in its molecular biology and capacity to cause persistent, noncytolytic CNS-infection in a wide variety of host species. Unlike other non-segmented negative-strand RNA animal viruses, BDV replicates in the nucleus of the host cell where splicing is employed for expression of a very compact genome. Epidemiological studies indicate a broad host range and geographical distribution, and some investigators have proposed that human infection may result in neuropsychiatric disorders. Experimental Borna disease in neonatal and adult rats provides an intriguing model for immune-mediated disturbances of brain development and function.

Animals↗

Fine structure and morphogenesis of Borna disease virus.

Borna disease virus (BDV), a negative nonsegmented single-stranded RNA virus, has not been fully characterized morphologically. Here we present what is to our knowledge the first data on the fine ultrastructure and morphogenesis of BDV. The supernatant of MDCK cells persistently infected with BDV treated with n-butyrate contained many virus-like particles and more BDV-specific RNA than that of untreated samples. The particles were spherical, enveloped, and approximately 130 nm in diameter; had spikes 7 nm in length; and reacted with BDV p40 antibody. A thin nucleocapsid, 4 nm in width, was present peripherally in contrast to the thick nucleocapsid of hemagglutinating virus of Japan. The BDV particles reproduced by budding on the cell surface.

Animals↗

Shrews as reservoir hosts of borna disease virus.

Borna disease virus (BDV) is the causative agent of severe T-cell-mediated meningoencephalitis in horses, sheep, and other animal species in central Europe. Here we report the first unequivocal detection of a BDV reservoir species, the bicolored white-toothed shrew, Crocidura leucodon, in an area in Switzerland with endemic Borna disease.

Animals↗

Preliminary studies on the biology of Borna disease virus.

Borna disease virus (BDV) is an unclassified agent that causes neurological disease in a wide range of animal species and possibly in humans. The infectious nature of BDV has been long established but, despite extensive progress on the pathogenesis of the infection, the aetiological agent is still uncharacterized. Recent studies have shown that BDV replicates productively in cultures of foetal rabbit glial cells (FRG) which produce a virus-specific protein that is easily detected immunocytochemically. This provides a marker for BDV infectivity. This cell culture system was used to investigate the replication cycle of BDV. The agent required at least 1 h to bind to and penetrate the cells and the antigen was detected 24 h later. Cycloheximide and actinomycin D inhibited production of the antigen in inoculated cells, indicating that both protein synthesis and a DNA-dependent function were required for the production of viral antigen. Cocultivation of BDV-infected FRG cells with Vero cells resulted in a persistent productive infection in the latter. Use of these cells showed that the infectious agent matured exclusively in the cytoplasm and within the plasma membrane of the cell. Antigen-laden nuclei did not have infectivity. These studies showed that BDV has the physical and replicative properties typical of conventional viruses but its mechanism of replication and site of morphogenesis may be unique.

Animals↗

A reverse genetics system for Borna disease virus.

Borna disease virus (BDV) is an enveloped virus. Its non-segmented, negative-stranded RNA genome has the coding capability for six main polypeptides and has an organization characteristic of members of the order Mononegavirales. However, based on its unique genetics and biological features, BDV is considered to be the prototypic member of a new virus family, Bornaviridae. Here, the establishment of a reverse genetics system for BDV is described. Intracellular synthesis of a BDV RNA analogue or minigenome (MG) from a plasmid was driven by RNA polymerase I. Co-transfection with plasmids expressing the BDV polymerase (L), nucleoprotein (N) and phosphoprotein (P) under the control of RNA polymerase II allowed for BDV MG replication and expression. This process depended on a delicate N:P ratio, whereas the L:P ratio was less critical. Two isoforms of N, Np40 and Np38, are present in BDV-infected cells but only Np40 was strictly required for virus polymerase activity. BDV p10 polypeptide encoded by the P gene exhibited a strong inhibitory effect on BDV MG expression.

Animals↗

Reverse-genetic approaches to the study of Borna disease virus.

Borna disease virus (BDV) is an enveloped virus that has a non-segmented, negative-strand RNA genome with the characteristic organization of the mononegaviruses. However, based on its unique genetic and biological features, BDV is considered to be the prototypic member of a new mononegavirus family, the Bornaviridae. BDV causes central nervous system (CNS) disease in a wide variety of mammals. This article discusses the recently developed reverse-genetics systems for BDV, and the implications for the elucidation of the molecular mechanisms underlying BDV-host interactions, including the basis of BDV persistence in the CNS and its associated diseases.

Animals↗

Neuropharmacological sequelae of persistent CNS viral infections: lessons from Borna disease virus.

Borna Disease Virus (BDV) is a neurotropic RNA virus that is worldwide in distribution, causing movement and behavior disorders in a wide range of animal species. BDV has also been reported to be associated with neuropsychiatric diseases of humans by serologic study and by recovery of nucleic acid or virus from blood or brain. Natural infections of horses and sheep produce encephalitis with erratic excited behaviors, hyperkinetic movement or gait abnormalities; naturally infected cats have ataxic "staggering disease." Experimentally infected primates develop hyperactivity, aggression, disinhibition, then apathy; prosimians (lower primates) have hyperactivity, circadian disruption, abnormal social and dominance behaviors, and postural disorders. However, the neuropharmacological determinants of BD phenotypes in laboratory and natural hosts are incompletely understood. Here we review how experimentally infected rodents have provided models for examining behavioral, pharmacologic, and biochemical responses to viral challenge, and how rodents experimentally infected as neonates or as adolescents are providing models for examining age-specific neuropharmacological adaptations to viral injury.

Animals↗

Identification and characterization of a new intron in Borna disease virus.

Borna disease virus (BDV) has a non-segmented, negative-strand (NNS) RNA genome. In contrast to all other known NNS RNA animal viruses, BDV replication and transcription occur in the nucleus of infected cells. Moreover, BDV uses RNA splicing for the regulation of its genome expression. Two introns (I and II), both present in two viral primary transcripts of 2.5 and 7.2 kb, have been reported in BDV. Here, evidence is provided of a new BDV intron, intron III, generated by alternative 3' splice-site choice. Intron III-spliced mRNAs were detected at early times post-infection and found to be present in cells from different types and species. Intron III-spliced mRNAs have coding capability for two new viral proteins with predicted molecular masses of 8.4 and 165 (p165) kDa. p165 is a deleted form of the BDV L polymerase, containing three RGD motifs and a signal peptide signal that could target it into the secretory pathway. These findings underscore the proteomic complexity exhibited by BDV.

Alternative Splicing↗

Isolation and characterization of a new subtype of Borna disease virus.

Borna disease virus (BDV), the causative agent of severe meningoencephalitis in a wide variety of animal species, has been considered to be genetically invariable and to form a single type within the genus Bornavirus of the family Bornaviridae. BDV infections are of particular interest, because for the first time a virus infection appears to be linked to human psychiatric disorders. We now describe a new subtype of BDV isolated from a horse which was euthanatized due to severe, incurable neurological disease. The nucleotide sequence of this new strain, named No/98, differs from the reference strains by more than 15%, and the subtype is difficult to detect by standard reverse transcriptase PCR protocols. The nucleotide exchanges of the novel BDV isolate have surprisingly little effect on the primary structures of most viral proteins, with the notable exception of the X protein (p10), which is only 81% identical to its counterpart in reference strains. Our data indicate that the genome of BDV is far more variable than previously assumed and that naturally occurring subtypes may escape detection by currently used diagnostic assays.

Animals↗

Sequence characterization of human Borna disease virus.

Borna disease virus (BDV) causes a central nervous system disease in several vertebrate animal species, which is manifest by behavioral abnormalities. Seroepidemiologic data suggest that BDV might infect humans, possibly being associated with certain mental disorders. This is further supported by the detection of both BDV-specific antigens and RNA sequences in peripheral blood mononuclear cells (PBMCs) of psychiatric patients. For the first time the sequence characterization of human BDV is documented here. BDV was recovered by co-cultivation techniques from the PBMCs of three hospitalized psychiatric patients. BDV was unequivocally identified based on sequence identification of BDV open reading frames (ORFs) p24, p16 and p56, as well as of the predicted catalytic domain of the BDV L polymerase. Each human BDV isolate had an unique sequence, but they displayed a high degree of sequence conservation with respect of BDV isolates from naturally infected animals of different species.

Adult↗

Molecular basis for the differential subcellular localization of the 38- and 39-kilodalton structural proteins of Borna disease virus.

Borna disease virus (BDV) is a nonsegmented negative-strand (NNS) RNA virus that is unusual because it replicates in the nucleus. The most abundant viral protein in infected cells is a 38/39-kDa doublet that is presumed to represent the nucleocapsid. Infectious particles also contain high levels of this protein, accounting for at least 50% of the viral proteins. The two forms of the protein differ by an additional 13 amino acids that are present at the amino terminus of the 39-kDa form and missing from the 38-kDa form. To examine whether this difference in amino acid content affects the localization of this protein in cells, the 39- and 38-kDa proteins were expressed in transfected cells. The 39-kDa form was concentrated in the nucleus, whereas the 38-kDa form was found in both the nucleus and cytoplasm. Inspection of the extra 13 amino acids present in the 39-kDa form revealed a sequence (Pro-Lys-Arg-Arg) that is very similar to the nuclear localization signals (in both sequence homology and amino-terminal location) of the VP1 proteins of simian virus 40 and polyomavirus. Primer extension analysis of total RNA from infected cells suggests that there are two mRNA species encoding the two forms of the nucleocapsid protein. In infected cells, the 39-kDa form is expressed at about twofold-higher levels than the 38-kDa form at both the RNA and protein levels. The novel nuclear localization of the 39-kDa nucleocapsid-like protein suggests that this form of the protein is targeted to the nucleus, the site for viral RNA replication, and that it may associate with genomic RNA.

Animals↗

Novel insights into the regulation of the viral polymerase complex of neurotropic Borna disease virus.

Borna disease virus (BDV) genetic information is encoded in a highly condensed non-segmented RNA genome of negative polarity. Replication and transcription of the genome occurs in the nucleus, enabling the virus to employ the cellular splicing machinery to process primary transcripts and to regulate expression of viral gene products. BDV establishes a non-cytolytic, persistent infection that in animals is mainly restricted to neurons of the central nervous system. Based on these unique properties, BDV represents the prototype member of the virus family Bornaviridae in the order Mononegavirales. Analysis of molecular aspects of BDV replication has long been hampered by the lack of a reverse genetics system. Only recently, artificial BDV minigenomes permitted the reconstitution of the viral polymerase complex, allowing finally the recovery of BDV from cDNA. As in other families of the Mononegavirales, the active polymerase complex of BDV is composed of the polymerase (L), the nucleoprotein (N) and the phosphoprotein (P). In addition, the viral X protein was identified as potent negative regulator of polymerase activity. Protein interaction studies combined with minireplicon assays suggested that P is a central regulatory element of BDV replication that directs the assembly of the polymerase complex. Most intriguingly, BDV obtained from cDNA with variable genomic termini suggests a novel strategy for viral replication-control. BDV seems to restrict its propagation efficacy by defined 5' terminal trimming of genomic and antigenomic RNA molecules. This review will summarize these novel findings and will discuss them in the context of BDV neurotropism and persistence.

Animals↗