A new method for extracting circular and supercoiled genome segments from cytoplasmic polyhedrosis virus

The genome of a cytoplasmic polyhedrosis virus (CPV) consisting of 10 segments was extracted by a new two-step extraction method. The results from polyacrylamide gel electrophoresis, phenol and diepoxybutane treatment and electron microscopic examination indicated the extracted genome segments to have circular and supercoiled structures as genome-protein(s) complexes. Multiple cycles of the transcription of each segmented genome of CPV may take place on the circular structure of the segment.