Technical Abstract: The genome of the 'oriculture pathogen Dahlia mosaic caulimovirus(DMV) encodes six openreading frames. Generally,caulimovirusgene VIproducts(P6s) are thought to be multifunctional proteins required for viral infection and it is likely that self-association is required for some of these functions. In this study,yeast two-hybrid and maltose binding protein(MBP) pull-down assay sindicated thatf ull-length DMV P6 speci'cally self-associates. Further analyses indicated that only the DMV P6 N-terminal region, consisting of 115 amino acids, interacts with fulllength P6 and with itself. This distinguishes the DMV P6 from its Cauli'ower mosaic virus counterpart, which contains four regions involved in self-association. Thus, our results suggest that each caulimovirus P6 may possess a unique pattern of protein protein interactions. Bioinformatic tools identi'ed a putative nuclear exclusion signal located between amino acid residues 10–20, suggesting another possible function for the P6 N-terminal region..