The genome-linked protein VPg of the Norwalk virus binds eIF3, suggesting its role in translation initiation complex recruitment.

The positive-strand RNA genomes of caliciviruses are not capped, but are instead covalently linked at their 5' ends to a viral protein called VPg. The lack of a cap structure typical of eukaryotic mRNA and absence of an internal ribosomal entry site suggest that VPg may function in translation initiation on calicivirus RNA. This hypothesis was tested by analyzing binding of Norwalk virus VPg to translation initiation factors.