Virus-specific RNA synthesis in the midgut of silkworm, Bombyx mori, infected with cytoplasmic-polyhedrosis virus

Virus-specific RNA synthesis in the midgut of silkworm infected with cytoplasmic-polyhedrosis virus was investigated under the condition inhibiting host RNA synthesis by actinomycin D injection. Two species of virus-induced RNA were formed; one was sensitive to ribonuclease (RNase) but the other was resistant. The resistant RNA had a sedimentation coefficient of 15 S and was considered as viral progeny with doublestranded RNA. The sensitive RNA, presumably single-stranded RNA, consisted of two classes with 15 S and 22 S sedimentation coefficients. Annealing the single-stranded RNA with heat-denatured CPV-RNA indicated that the single-stranded RNA was transcribed from viral genome RNA. The function of 22 S and 15 S single-stranded RNAs was discussed from the viewpoint of virus multiplication.