Transcriptome analysis of Mastomys natalensis papillomavirus in productive lesions after natural infection.

Mastomys coucha, an African rodent, is a useful animal model of papillomavirus infection, as it develops both premalignant and malignant skin tumors as a consequence of a persistent infection with Mastomys natalensis papillomavirus (MnPV). In this study, we mapped the MnPV transcriptome in productive lesions by both classical molecular techniques and high-throughput RNA sequencing. Combination of these methods revealed a complex and comprehensive transcription map, with novel splicing events not described in other papillomaviruses. Furthermore, these splicing occurrences could potentially lead to the expression of novel E2, El boolean AND E4, E7 and L2 isoforms. Expression level estimation of each transcript showed that late region mRNAs considerably outnumber early transcripts, with species coding for L1 and E1 boolean AND E4 being the most abundant. In summary, the full transcription map assembled in this study will allow us to further understand MnPV gene expression and the mechanisms that lead to natural tumour development.