The most obvious potential non-AUG codon for the first type of reinitiation event is the AUA codon located immediately upstream (-1 position) of the wild-type reinitiation site at +1 ( Figure 6A ). We therefore tested whether reinitiation can indeed occur at this -1 position, by generating an AUG in this position and removing the wild-type +1 AUG. The results showed that the efficiency of reinitiation at an AUG in the -1 position was similar to when it was in the normal (+1) position ( Figure 6B , compare lanes 8 and 10), in agreement with the finding that reinitiation efficiency in the RHDV system was only slightly compromised if the restart codon was moved one codon upstream [19] . Given that quite efficient reinitiation still occurs in FCV and BM2 RNAs when the wild-type AUG is mutated to non-AUG codons [11, 15, 17] , this observation suggests that when the wild-type +1 AUG has been mutated, there is a strong possibility of some reinitiation occurring at the -1 AUA codon.