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. 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. 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.