Increases viral DNA accumulation. Enhances infectivity and symptom expression. Homooligomer. Interacts with the replication-associated protein (REP). Interacts with host proliferating cell nuclear antigen (PCNA). Interacts with host retinoblastoma-related protein 1 (RBR1), and may thereby deregulate the host cell cycle. Oligomerization and interaction with PCNA are necessary for optimal replication enhancement (By similarity). Belongs to the geminiviridae replication enhancer protein family.