Essential for the replication of viral ssDNA. The closed circular ssDNA genome is first converted to a superhelical dsDNA. Rep binds a specific region at the genome origin of replication. It introduces an endonucleolytic nick within the conserved sequence 5'-TAATATTAC-3' in the intergenic region of the genome present in all geminiviruses, thereby initiating the rolling circle replication (RCR). Following cleavage, binds covalently to the 5'-phosphate of DNA as a tyrosyl ester. The cleavage gives rise to a free 3'-OH that serves as a primer for the cellular DNA polymerase. The polymerase synthesizes the (+) strand DNA by rolling circle mechanism. After one round of replication, a Rep-catalyzed nucleotidyl transfer reaction releases a circular single-stranded virus genome, thereby terminating the replication. Displays origin-specific DNA cleavage, nucleotidyl transferase, ATPase and helicase activities (By similarity). Divalent metal cations, possibly Mg(2+) or Mn(2+). Homooligomer. Interacts with the replication enhancer protein (REn). Interacts with host retinoblastoma-related protein 1 (RBR1), and may thereby induce the transcription of host replicative enzymes even if the cell is not dividing anymore. Interacts with host PCNA. Interacts with host SCE1 protein (By similarity). There are 3 rolling circle replication (RCR) motifs. RCR-2 is probably involved in metal coordination. RCR-3 is required for phosphodiester bond cleavage for initiation of RCR (By similarity). Belongs to the geminiviridae Rep protein family.