MOLECULAR CHARACTERIZATION OF THE DNA OF ANATID HERPESVIRUS-1

A plaque-purified isolate of the Holland strain of Anatid herpesvirus (AHV-ppc3) was purified by differential and buoyant density sedimentation. The virus buoyant density was 1.215 g/cm3 in sucrose. AHV-ppc3 DNA was analyzed by sedimentation velocity studies in neutral or alkaline sucrose gradients. Based upon a comparison with T4 DNA, the DNA of AHV-ppc3 was found to have a sedimentation coefficient of 59.7 S and a molecular mass of 1.19 x 10(8) daltons. Between 15 and 22 bands were observed in agarose gel electrophoresis with AHV DNA cut by BamHI, EcoRI, PstI or Bg/II. The possibility of isometric forms is indicated by the finding of restriction fragments having molar ratios differing from 1.0. The mean molecular mass calculated from the fragments was 1.18 x 10(8) daltons. Terminal fragments were identified using exonuclease II and BgII. In alkaline sucrose gradients, AHV DNA fragments with the largest of the most abundant species have a sedimentation coefficient of 69 S and a calculated mass of 6.0 x 10(7) daltons. The buoyant density of AHV-ppc3 DNA in cesium chloride was 1.723 g/cm3 corresponding to a % G + C content of 64.3. This finding was supported by thermal melts of the DNA in SSC/10 in which the thermal melting point was 82.7-degrees. The data support a model for AHV in which the viral duplex DNA is linear, without covalently closed termini or significant base modifications, but with single strand nicks or gaps. The % G + C content of AHV DNA is the highest reported for any avian herpesvirus in the alpha-herpesvirinea subgroup.