InterPro domain: IPR000211

The movement of bipartite Geminiviruses such as squash leaf curl virus (SqLCV) requires the cooperativeinteraction of two essential virus-encoded movement proteins, BR1 and BL1. Recent studies of SqLCV and bean dwarf mosaic virus have shown that BR1 and BL1 act in a cooperative manner to move the viral genome intracellularly from the nucleus to the cytoplasm and across the wall cell to cell. BR1 is a nuclear shuttle protein, and it has been proposed to bind newly replicated viral ssDNA genomes and move these between the nucleus and cytoplasm. These BR1-genome complexes are then directed to the cell periphery through interactions between BR1 andBL1, where, as the result of BL1 action, the complexes are moved to adjacent uninfected cells. The precisemechanism by which BL1 acts to transport these genome complexes across the cell wall, and whether this may differ in different celltypes, remains at issue [ 1 ].

1. The bipartite geminivirus coat protein aids BR1 function in viral movement by affecting the accumulation of viral single-stranded DNA. J. Virol. 72, 9247-56