Viral messengers were used to select and purify prosomes and prosomal RNA from subribosomal fractions of HeLa cells and mouse erythroblasts. Adenovirus mRNA immobilized on oligo(dT)-cellulose and tobacco mosaic virus RNA (TMV) sedimenting in sucrose gradients associated strongly with prosomes at high salt conditions forming intermolecular RNA-RNA hybrids between prosomal RNA and viral RNA. Hybrid selection of small cytoplasmic RNAs with immobilized TMV-RNA revealed a RNA species migrating at the same position as prosomal RNA. The possible existence of a box-like sequence involved in hybridization will be discussed.
