Herpesvirus cyprini: Restriction Endonuclease Cleavage Profiles of the Viral DNA.

Herpesvirus cyprini (CHV) has been isolated from papillomatous tissue of carp cultured in Niigata Prefecture in 19811) . We reported its biological properties2) and lethality and on cogenicity to carp fry3) . In this paper, we describe the restriction endonuclease profiles of CHV DNA, and molecular weights calculated from the fragments of the DNA, and com parison of the cleavage patterns between two isolates. CHV used in our previous studies was designated as Niigata isolate to compare another isolate in this study. The virus harvested from infected FHM cell at 20•Ž, was precipitated with polyethylene glycol 6000, suspended in the buffer (30 mM Tris, pH 7.5, 152 mM KCl, 0.5 mM EDTA 6 mM 2-mercaptoethanol), and then added 5% de oxycholic acid, DNase (Sigma, Type IV) and RNase (Sigma, Type I AS) at 15 ƒÊg/ml final concentration, respectively, followed by incuba tion at 30•Ž for 30 min. The finally obtained nucleocapsid was pelleted through sucrose gra dient (10% and 20%) by centrifugation at 100,000 g for 1 h, and were resuspended in the buffer (30 mM Tris-HCl, pH 7.5 at 37•Ž, 2% SDS, 5 mm EDTA) . The viral DNA was ex tracted from the partially purified nucleocapsid by digestion with proteinase K (wako, Osaka, Japan) and by subsequent treatment with phenol and chloroform. The exracted genome DNA was digested with Kpn J, Xba I, Bgl I, Sma I (Toyobo, Osaka, Japan) under each suitable condition. The frag ments of the digested DNA were electrophoresed at 27 mA for 16 h at room temperature on a 0.8% horizontal agarose gel in the buffer con taining 40 mm Tris-5 mM sodium acetate-1 mM EDTA (pH 7.6) . The gel was stained with ethidum bromide and photographed on UV transilluminator (Fig. 1) . The molecular weights of fragments of Niigata isolate were estimated