Polyomavirus

Patent Granted Polyomaviruses are DNA-based (double-stranded DNA, ~5000 base pairs, circular genome) viruses. They are small (40–50 nanometers in diameter), and icosahedral in shape, and do not have a lipoprotein envelope. Moreover, the genome possess early and late genes, contributing to its complex transcription program. They are potentially oncogenic (tumor-causing); they often persist as latent infections in a host without causing disease, but may produce tumors in a host of a different species, or a host with an ineffective immune system. The name polyoma refers to the viruses' ability to produce multiple (poly-) tumors (-oma).