Bornaviridae: Borna Disease Virus
Bornaviruses are so named for the
town in Germany where they were first described in 1776 as an infection
of
horses. The virus has since been discovered to be prevalent in humans
and
a wide variety of animals. Its mysterious association with
neuropsychiatric
disorders has made borna disease virus (BDV) an exciting new topic in
medical
research.
BDV is a negative-sense, monopartite, single stranded RNA virus.
The enveloped
viron appears spherical and contains a helical capsid. It is a
non-lytic,
persistent, neurotropic virus. Bornaviridae is classified in the order
Mononegavirilies,
but unlike other families of this order BDV replicates in the host
nucleus
and has overlapping transcriptional units, some of which undergo
splicing
by the cellular machinery. BDV has three transcriptional units
and at least
six proteins listed below:
Unit 1
Unit 2 - overlapping
- x protein (X) (a negative regulator of the
polymerase)
Unit 3 - overlapping, regulatory
splicing