The Replication of Bacteriophage MS2: VIII. Fractionation of the "Replicative Intermediate" using a BNC Column

Abstract

The template on which single strands of MS2 RNA are synthesized, often called the replicative intermediate, is a partially double-stranded molecule. This unusual secondary structure permits the purification of the replicative intermediate on columns of benzoylated, naphthoylated DEAE cellulose (BNC), which have been shown to fractionate nucleic acids with respect to the extent of their double-stranded character. The replicative intermediate is eluted from such a column after DNA and before single-stranded MS2 RNA, but shows heterogeneity. The fractions of replicative intermediate which are eluted at higher sodium chloride concentrations are more sensitive to RNase and have a buoyant density closer to that of single-stranded RNA. The results suggest that the replicative intermediate molecule consists of a double-stranded "core" to which is attached one singlestrand tail of variable length and that these molecules are fractionated on the BNC column with respect to their tail length. All the fractions of replicative intermediate are infective upon denaturation.

Additional details