Essential for the replication of viral ssDNA. The closed circular ssDNA genome is first converted to a superhelical dsDNA. Rep and/or Rep' binds a specific hairpin at the genome origin of replication. Introduces an endonucleolytic nick within the conserved sequence 5'-AGTATTAC-3' in the intergenic region of the genome, 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, and nucleotidyl transferase. ATP + H2O = ADP + H(+) + phosphate Divalent metal cations, possibly Mg(2+) or Mn(2+). Interacts with the capsid protein; this interaction relocates Rep into the nucleus. 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. Produced by alternative promoter usage. Produced by alternative splicing of isoform Rep. Produced by alternative promoter usage. Produced by alternative promoter usage. Produced by alternative splicing of isoform Rep. Produced by alternative splicing of isoform Rep. Produced by alternative splicing of isoform Rep. Belongs to the nanoviruses/circoviruses replication-associated protein family.