Demonstration of adenovirus associated endonuclease

In HEp-2 and amnion cell cultures infected with type 1 adenovirus the DNase activity of cell extracts was measured on 32P-labelled Escherichia coli DNA substrate. Enzyme activity was demonstrated by the acid soluble nucleotides released from the 32P-DNA and by the decreased sedimentation rate of labelled DNA. High DNase activity was measured in both adenovirus infected and in untreated HEp-2 cell extracts. Nuclease activity of the amnion host cells being much lower than that of HEp-2 cells, virus-associated endonuclease activity was successfully demonstrated in them. Purified type 1 adenovirus decreased the sedimentation rate of 32P-labelled E. coli DNA. The phenomenon is explained by the virion-associated endonuclease activity. Trypsin inactivated and anti HEp-2 IgG failed to inhibit the virion nuclease. An association between endonuclease and trypsin sensitive penton is assumed.