Bornaviruses occupy a special place within Mononegavirales (virus with a non-segmented RNA genome). They infect the widest range of species of the animal kingdom, ranging from fishes to mammals. They replicate in the nucleus, where they assemble viral factories (viral Speckles Of Transcripts, vSPOTs) in close vicinity with the neuron chromatin. It has been recently shown that some mammalian orthobornaviruses (e.g., Borna disease virus 1 (BoDV-1) and variegated squirrel bornavirus 1 (VSBV-1)) can infect humans, predominantly affecting neuronal tissues and causing fatal encephalitis. The genome of bornaviriruses consists of approximately 8900 nucleotides and represents the smallest known genome amongst Mononegavirales.
BoDV-1 replication machinery, a complex between the RNA-dependent RNA polymerase (RdRp or L) and the phosphoprotein (P), produces different mRNAs from the genome via polar sequential transcription, encoding for a total of six viral proteins. Except for the RNA-free nucleoprotein (N) and the matrix protein, nothing is known concerning the structure of these viral proteins.
Structural analysis of orthobornaviral POD. Experimental SAXS diffusion curves of (a) BoDV-1, (b) MuBV-1, and (c) GaVV-1 POD. Low-resolution envelops of (d) BoDV-1, (e) MuBV-1, and (f) GaVV-1 POD based on the ab initio modelling. X-ray structure of (g) BoDV-1, (h) MuBV-1, and (i) GaVV-1 POD. (j) Sequence alignment of the corresponding POD with the secondary structures of BoDV-1 and GaVV-1, shown above and below the sequence alignment, respectively.
The team works on the different partners of the replication machinery.