Single-stranded RNA Synthesis in Vitro by the RNA Polymerase Associated with Cytoplasmic Polyhedrosis Virus Containing Double-stranded RNA

Abstract

RNA polymerase associated with cytoplasmic polyhedrosis virus, which contains double-stranded RNA as a genome, synthesizes single-stranded RNA in vitro. The optimal conditions for RNA synthesis by this enzyme were investigated. The RNA product has the same size distribution as the genome segments, showing two fractions on glycerol concentration gradient centrifugation. Each fraction of the synthesized RNA hybridized specifically with the corresponding size fraction of denatured genome RNA segments. Only after transcription has been carried out over the whole length of each genome segment does the single-stranded RNA product leave the virus particle. It seems that the transcription of every segment starts at the same time, although the transcribed RNA for the shorter segment group is released from the virion faster than that for the larger group. This work was partly supported by grants from the Ministry of Education of Japan and the Naito Foundation.