CVB3/TD viruses have VPg covalently attached to genomic RNA. (A) Alignment of amino-terminal sequences of VPg between CVB3/28 and PV1. Differences are boxed. (B) Viral RNA was purified from stocks of the CVB3/28, TD8, and TD50 viruses (105 TCID50 units) and analyzed by Western blotting. Blots were probed with antibody to PV1 VPg (N10) as described in Materials and Methods. RNA treated with RNase A/T1: PV1 Sabin (lane 1), CVB3/28 (lane 2), CVB3/TD8 (lane 3), and CVB3/TD50 (lane 4); RNA treated with RNase A/T1 and proteinase K: CVB3/28 (lane 5), CVB3/TD8 (lane 6), and CVB3/TD50 (lane 7); untreated RNA: CVB3/TD8 (lane 8) and CVB3/TD50 (lane 9).