Molecular characterization of the Nyamaninivirus (NYMV): Identification and analysis of viral protein functions in the NYMV replication cycle
Final Report Abstract
Scientific achievements: - We demonstrated that NYMN replicates its genome in the nucleus of infected host cells. - We found that reconstitution of viral polymerase activity was only obtained if the viral gene 3 was co-expressed with the viral N and L genes. This was surprising as in other negative-strand RNA viruses the second gene of the linear viral genome encodes an essential polymerase cofactor. - We observed that the viral gene 2 encodes a factor that negatively regulates viral polymerase activity - We further managed to demonstrate that viral particle formation requires the simultaneous expression of the viral G genes and, surprisingly, not only the viral M gene but rather both M and gene 2. - We established a “reverse genetic” system with the help of which the genome of NYMV can be manipulated, and we successfully generated a NYMV variant that expresses green fluorescent protein. - Using the reverse genetic system we demonstrated that gene 2 serves essential functions in the viral life cycle. - Interestingly, we were able to generate a viable virus mutant that lacks the M gene. Unlike wild-type NYMV, this mutant virus was unable to release infectious particles into the culture medium. However, the M-deficient virus established long-term persistence in its host cells and was able to spread to uninfected cells by cell-to-cell contact. - Finally, we showed that the viral genome is mono-phosphorylated like the genome of bornaviruses and that, as a consequence, NYMV is a relatively poor inducer of innate immune responses. Our results were received well by the research community and formed the basis for a first classification of NYMV by the International Committee on Taxonomy of Viruses (ICTV). Based on our work, the new family “Nyamiviridae” was created.
Publications
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Tick-borne Nyamanini virus replicates in the nucleus and exhibits unusual genome and matrix protein properties. J. Virol. 86: 10739-10747 (2012)
Herrel, M., Hoefs, N., Staeheli, P., & U. Schneider
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Reverse genetics identifies the product of open reading frame 4 as essential particle assembly factor of Nyamanini virus. J. Virol. 87: 8257-8260 (2013)
Herrel, M., Haag, L., Nilsson, J., Staeheli, P., & U. Schneider
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“Nyamiviridae” – Proposal for a new family in the order Mononegavirales. Arch. Virol. 158: 2209-2226 (2013)
Kuhn, J.H., Bekal, S., Caì, Y., Clawson, A.N., Domier, L.L., Herrel, M., Jahrling, P.B., Kondo, H., Lambert, K.N., Mihindukulasuriya, K.A., Nowotny, N., Radoshitzky, S.R., Schneider, U., Staeheli, P., Suzuki, N., Tesh, R.B., Wang, D., Wang, L-F., & R.G. Dietzgen
