Sequence of the black beetle virus subgenomic RNA and its location in the viral genome

BBV (black beetle virus) RNA3, the subgenomic messenger RNA for BBV protein B and its double-stranded form (dsRNA3) were purified from cells infected with BBV and were sequenced. RNA3 is 389 bases long. The sequence is homologous to that of the 3'-terminal region of virion RNA1. RNA3 has a very limited homology to virion RNA2. RNA3 is capped at its 5' terminus and has a structural feature at its 3' terminus that renders it inert to the action of the enzymes RNA ligase and poly(A) polymerase. RNA3 has two overlapping reading frames for putative proteins of size 10,768 and 11,633 Da. The positive and negative strands of dsRNA3 are not capped and correspond in length and sequence to RNA3 itself.