Orf virus (ORFV) ANK-1 protein mitochondrial localization is mediated by ankyrin repeat motifs
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Orf virus (ORFV) strain D1701-V, a Parapoxvirus belonging to the family Poxviridae, became attractive as a novel virus vector system that we successfully used for the generation of recombinant vaccines. Therefore, the identification of viral genes involved in host tropisms or immune modulation is of great interest, as for instance the ORFV-encoded ankyrin-repeat (AR) containing proteins. The present study shows for the first time that the ANK-1 designated gene product of ORFV126 is targeted to mitochondria of ORFV-infected and in ANK-1 transiently expressing cells. Taking advantage of ANK-1 EGFP fusion proteins and confocal fluorescence microscopy mutational and deletion analyses indicated the importance of AR8 and AR9, which may contain a novel class of mitochondria-targeting sequence (MTS) in the central to C-terminal part of this AR-containing protein. The fluorescent findings were corroborated by cell fractionation and Western blotting experiments. The presented results open the avenue for more detailed investigations on cellular binding partners and the function of ANK-1 in viral replication or virulence.
KeywordsParapoxvirus Gene ORFV126 Ankyrin-repeat protein Mitochondria
The help of Timo Fischer during transfection and construction of the ANK-1 pcDNA plasmid is gratefully acknowledged. The helpful comments and critically reading of the manuscript of Ralf Amann and Jörg Rohde is greatly appreciated. The project was supported by Polish National Science Centre grant no. 2012/04/A/NZ1/00056. Krzysztof Lacek was also supported by the EU Leonardo da Vinci Programme II (Mobility Projects Partnership Quality Commitment Placements).
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