Activities associated with the putative replication initiation protein of Coconut foliar decay virus, a tentative member of the genus Nanovirus

The putative replication initiation protein (Rep) of Coconut foliar decay v irus (CFDV) was expressed as a 6 x His recombinant protein in E. coli and i n recombinant baculovirus. Purified 6 x His-Rep protein was demonstrated to possess sequence non-specific RNA- and ssDNA-binding activities as well as magnesium-dependent ATPase/GTPase activity. The yeast two-hybrid system re vealed that CFDV Rep could interact with itself. Subcellular distribution o f the CFDV Rep was studied by fractionation of insect cells infected with r ecombinant baculovirus expressing the 6x His-Rep protein and by laser scann ing confocal microscopy of Nicotiana benthamiana epidermal cells bombarded with a construct encoding CFDV Rep fused to GFP. It was shown that CFDV Rep associated predominantly with nuclei and mem branes of infected/transfecte d cells. These activities of CFDV-encoded Rep are very similar to those rep orted for Reps of geminiviruses.