Homologous Terminal Sequences in the Double-Stranded RNA Genome Segments of Cytoplasmic Polyhedrosis Virus of the Silkworm Bombyx mori

Abstract

The 3'-terminal regions (20 to 32 residues) of the genome double-stranded RNA (dsRNA) segments of cytoplasmic polyhedrosis virus were sequenced. The dsRNAs, which were labeled at their 3' termini by incubation with [5'-(32)P]pCp and T4 RNA ligase, were denatured and resolved into the plus and minus strands by agarose-urea gel electrophoresis. Ten single-stranded RNAs thus obtained from the five dsRNA segments IV, V, VIII, IX, and X were sequenced by postlabeling methods. Common 3'-terminal sequences, -GUUAGCC and -UUACU, were found in the plus and minus strands, respectively, of all five dsRNA segments. However, adjacent sequences diverged and were considerably variable. The homologous sequences found in the 3' end may be important recognition signals for viral RNA polymerases and for assembly of the genome segments.