The Size and Location of the Poly(A) Tract in EMC Virus RNA

Abstract
Encephalomyocarditis (EMC) virus RNA, selected by its affinity for oligo(dT)-cellulose, contains poly(A) of size: (i) about 14 nucleotide residues long, based on the percentage of radioactivity in the RNA resistant to digestion by a mixture of pancreatic and T1 RNases; (ii) about 15 residues long, as measured by the ratio of the amount of terminal adenosine to internal adenylic acid in isolated poly(A); and (iii) in the range 12 to 45 residues, the majority of tracts being about 16 to 18 residues long, based upon electrophoretic mobility on polyacrylamide gels using poly(A) molecules of known size as mol. wt. markers.