Isolation and characterization of Borna disease agent cDNA clones.

Abstract

Borna disease (BD) is a neurologic syndrome characterized by behavioral disturbances and the accumulation of specific proteins in limbic system neurons. A viral etiology has been proposed because BD can be induced in birds, rodents, and primates by inoculation with filtered brain homogenates from animals with BD. We report here the isolation and preliminary characterization of cDNA clones from a rat with BD. These clones hybridized to specific transcripts in BD rat brain and arrested in vitro translation ofBD proteins. In situ hybridization experiments using RNA probes prepared from these clones showed an abundance of these transcripts in limbic system neurons. Northern (RNA) hybridizations using these RNA probes indicated that the BD agent is probably a virus with major transcripts of 8.5, 2.1, and 0.8 kilobases.Borna disease (BD) is an immune-mediated neurologic syndrome characterized by profound abnormalities in behavior. Although BD was initially described as an epidemic disease in horses and other livestock, the disease has been experimentally induced in a wide variety of vertebrates, including birds, rodents, and primates, through inoculation of filtered brain extracts from infected animals (1-6). Because the potency of such extracts to induce disease is reduced by exposure to UV or detergents, the BD agent has been suggested to be an enveloped virus (1, 7).Animals with BD produce antibodies that recognize 60 kDa, 38/40-kDa, 25-kDa, and 14.5-kDa proteins in brains of infected animals and in infected cell cultures (1,3,8,9). These proteins are thought to be encoded by the BD agent because they are present in all animals with BD and because antibodies from one host species recognize the same panel of proteins in other species with BD (1,3,8,9).The behavioral manifestations of BD vary with the host species. Birds and livestock show motor disturbances (1, 3). Rats have a biphasic course. The acute phase is characterized by displays of aggression, hyperactivity, and ataxia; this phase is followed over a period of several weeks by listlessness, blindness, and, in some animals, by paralysis or obesity (4,5). These biphasic abnormalities in rat behavior have been correlated with specific alterations in neurotransmitter mRNA levels (6). Tree shrews show abnormalities in social and sexual behaviors (2). In each of these host species, BD proteins are present primarily in limbic system neurons (1,3,5). Recent studies suggest that the host range for BD may extend to man. Antibodies to BD proteins have been described in patients with bipolar depressive disorders, in intravenous drug abusers, and in individuals seropositive for human immunodeficiency virus (10)(11)(12).Interest in BD as a model for virus-induced behavioral disorders and recognition ofthe potential role of BD in human neuropsychiatric disease led us to attempt characterization of the BD agent. Because classical methods for purification of viral particles had not been successful, we adopted a recombinant DNA approach to study this unusual infectiou...

Novel Borna Virus in Psittacine Birds with Proventricular Dilatation Disease

“…Thus, it will be important to revisit epidemiologic surveys that we, and others, have undertaken to investigate the role of bornaviruses in human disease (14). From a personal perspective, we are intrigued that whereas molecular discovery of the fi rst BDV in the late 1980s required an investment of 2 years in subtractive cloning (15), high-throughput sequencing, bioinformatics, and sequence databases enabled discovery of these 2 strains in 2 weeks. A tree representing the evolutionary history was inferred by using the neighbor-joining method.…”

Staggering disease in cats: isolation and characterization of the feline Borna disease virus

“…Selection of primers, probe and reagents. The oligonucleotides were designed according to published sequences from the cDNA clone pAB5 encoding the 40 kDa protein (Lipkin et al, 1990) using the computer program OLIGO, version 4.0. The primer sequences have been described previously (Zimmermann et al, 1994a).…”

“…For Southern hybridization, an 800 bp EcoRV insert of the plasmid pAB5 (Lipkin et al, 1990) was used as the probe.…”

Neonatal Borna disease virus infection in the rat causes a loss of Purkinje cells in the cerebellum

“…Borna disease virus (BDV) is a single-strand RNA virus which replicates in the nervous system of many species after experimental inoculation (Carbone et al, 1987;de la Torre et al, 1990;Lipkin et al, 1990) and causes acute neurologic disease which, evidently, is somewhat variable in its outcome at least partly due to the strain of BDV used. The manifestations of the infection, which is often lethal, are typically characterized by ataxia, hyperactivity and aggressive behavior.…”