Figure 4.

Replication cycle of plant pararetroviruses (Starting clockwise at 12 h): A virus particle containing open circular DNA has entered the cell. Its DNA is imported into the nucleus, where the gaps/overhangs are repaired to yield supercoiled dsDNA. Terminally redundant RNA is produced and transported into the cytoplasm. RNA copies are translated into virus proteins and/or packaged as two copies into virus particles. There reverse transcription occurs. The resulting open circular dsDNA reenters the replication cycle. In the lower left is shown how recombination can occur by template switching. On the right is shown how very rarely fragments of virus DNA incorporate into the plant genome, leading to endogenous viral sequences.