The 5′-end structure of potato virus X RNA was determined following enzymatic methylation invitro A single 3 H group was introduced into the 2′-position of the 5′-penultimate residue and the end structure was determined as m 7 GpppG (m) pAp(Xp)3G. This part of the RNA apparently is involved in binding to ribosomes since it can be partially protected against RNase digestion by wheat germ 40S ribosomes. PVX RNA was not retained by poly(U)-sepharose, indicating that it does not contain a 3′-terminal poly(A) tract.

Author notes

* Present address: Biology Department, Brandeis University, Waltham, MA 021 54, USA