Fig. 8

Model of the life cycle of retrozymes. A full genomic retrozyme containing at least two HHRs (top) is transcribed. The resulting RNA would self-process through the HHRs to give a linear RNA with 5′-OH and 2′-3′-cyclic phosphate ends, which would be circularized. The resulting circRNA(+) would be template for either endogenous RNA polymerases (replication cycles) and/or retrotranscriptases encoded by LTR-retrotransposons. In the latter case, the cDNAs resulting from retrotranscription of a circular RNA template could have different lengths (solo LTR, monomeric or multimeric) depending on the processivity of the retrotranscriptase. Finally, the machinery of the LTR-retrotransposon would integrate the retrozyme DNAs at a new genomic location