This represents a dramatic difference between papillomaviruses and polyomaviruses, since the latter virus type expresses its early and late genes by bi-directional transcription of both DNA strands.
See on suur erinevus papilloomiviiruste ja polüoomiviiruste vahel, kuna viimases ekspresseeritakse varajased ja hilised geenid bipolaarse transkriptsiooniga mõlemalt DNA ahelalt.