A structural model for the genome of echovirus 22

Summary We have proposed previously that the structural model for the echovirus 22 genome is a single-stranded RNA molecule that has folded back upon itself to form a stable hairpin at the 5-terminus. The vRNA of echovirus 22 has been characterized further by digestion with selective ribonucleases, electrophoresis in composite gels, hydrodynamic studies in density gradients of Cs₂SO₄ and sucrose, thermal denaturation and 3-terminal ribonucleotide analysis. Based on these observations, the genome of echovirus 22 is a single-stranded RNA molecule having a region of secondary structure located at the 5-terminus that may be characterized as a snapback hairpin with hydrogen-bonded base-pairing. In addition, a VPg-like protein is attached (presumably to the 5-end of the RNA) and the 3-terminus contains a polyadenylic acid tract poly(A)].