FIG. 2.

Murine norovirus 3′-end mutants. Schematic representation of the MNV 3′ end, highlighting the various deletion and point mutants under study. The diagram at the top left highlights the nucleotide positions of the various stem-loops, SL1 to SL3, and the GA-rich sequence in SL2 deleted in the corresponding mutants. The positions of the nucleotide alterations in SL2 ssm, SL3 ssm, and SL3 ssm R are highlighted with filled circles or squares, with the corresponding changes introduced shown offset in the open circles or squares. The predicted secondary structures of SL3 in the SL3 ssm NR mutant, with the deleted sequence boxed, in SL3 GNRA, and in SL3 AAAA are also shown. Note that for the purposes of this figure, the base pairing predicted to occur between the poly(A) tail and the MNV 3′ UTR has been omitted. In addition, the schematics for SL2 ssm, SL3 ssm, SL3 ssm R, and SL3 ssm NR are for illustrative purposes only, since the predicted secondary structure is significantly modified by the introduced mutations.