A comprehensive study of polyprotein processing within the murine norovirus (MNV) suggests likely identities for the equivalent proteins in the similar profile for JV [12] . Using region specific antisera the authors were able to identify p110 as the 3ABCD uncleaved precursor, p90 as the 3BCD, p57.5 as the 3D-like polymerase, p52 as a 3ABC precursor and p40 as the 2Clike NTPase, which was determined by mutagenesis and microsequencing experiments. The 19 kDa protein was identified as the 3C-like protease. The antisera used to detect the MNV Nterm protein recognised 3 products; one was the predicted molecular weight at 39 kDa and the other two bands migrated as a 45 kDa doublet.