Putative stimulatory elements for ribosomal -1 frameshifting. (A) The slippery heptanucleotide and predicted 3' RNA pseudoknot structure for JEV [GenBank:NC_001437]. (B) Sequence alignment of different JEV-group sequences, showing the conserved presence of a slippery heptanucleotide (Y CCU UUU; orange) and potential to form a 3' RNA pseudoknot. Base-pairings in stem 1 are indicated with '()'s and yellow background while base-pairings in stem 2 are indicated with ''s and green background. Base substitutions that preserve base-pairings or the slippery heptanucleotide are highlighted in red. Viruses: Japanese encephalitis (JEV) – [GenBank:NC_001437]; West Nile (WNV; lineage I) – [GenBank:NC_009942]; West Nile (WNV; lineage II) – [GenBank:NC_001563]; Kunjin – [GenBank:AY274504]; Murray Valley encephalitis (MVEV) – [GenBank:NC_000943]; Alfuy – [GenBank:AY898809]; Usutu – [GenBank:NC_006551].