Figure 1. The gene P of TioV encodes for three proteins: V, W and P.

Whereas conventional transcription and translation lead to the expression of TioV-V, co-transcriptional insertion of one G residue at the editing site by the viral RNA polymerase leads to the expression of a chimeric protein called W. Insertion of two G residues can also occur during transcription, thus leading to the expression of the phosphoprotein P.