None enveloped virus of icosahedral symmetry with 72 capsomers that surround a genome containing doouble stranded DNA of apprx 8000 base pairs. these genome are divided into 3 functional regions:

1) (E) region: codes for 6 non structural genes associated with cellular transformation 2) (L) region: 2 structural protiens: L1 and L2 that form the capsid 3) (C) noncoding long control region: regulates replication and gene function