Comparison of packaging strategy in retroviruses and pararetroviruses

Reverse transcription is not solely a retroviral mechanism. Animal hepadnaviruses, plant caulimoviruses, and badnaviruses have a RNA intermediate which is reverse transcribed into double-stranded DNA genome. Based on this fact, these three groups of viruses have been regrouped under the name of pararetroviruses. Although each one has developed its own strategy to assure an efficient packaging of their genome, it is clear that they have adopted a strategy where encapsidation prepares for initiation of reverse transcription. This is discussed in this review.