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. Acts as an inhibitor of C-sense gene transcription (By similarity). Divalent metal cations, possibly Mg(2+) or Mn(2+). Homooligomer. Rep binds to repeated DNA motifs (iterons). Forms the O-complex, which is a Rep-DNA complex involved in the initiation of RCR. Part of the C- and V-complexes which are RepA-Rep-DNA complexes involved in the c-sense and v-sense transcription. 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. Belongs to the geminiviridae Rep protein family.