Differences in transcriptional activity of cutaneous human papillomaviruses

The interaction between UV-B irradiation and cutaneous human papillomaviruses (HPV) has been suggested to be of relevance for the development of non-melanoma skin cancers. We investigated the activity within the upstream regulatory region (URR) of the HPV types 8, 38, 92, 93 and 96, as well as their responsiveness to UV-B irradiation and cellular differentiation. Promoter activities were higher in HaCaT than in SiHa cells, corresponding to the HPV tissue tropism. Transcriptional start sites were mapped at P92 (HPV-38), P45 (HPV-92), P7439 (HPV-93) and P256 (HPV-96). Transcription from HPV-8, 93 and 96 URR was up-regulated by cellular differentiation, linking the activity of these HPVs to the cellular state. UV-B irradiation activated HPV-8 but inhibited HPV-38 and HPV-93 whereas HPV-92 and 96 were not affected. As there are variable UV-B responses among the HPV types, further studies of interactions between UV-B and HPV need to consider the HPV type.