A novel lineage-tracing mouse model for MmuPV1 infection enables in vivo studies in the absence of cytopathic effects

Human papillomaviruses (HPVs) are DNA viruses that ubiquitously infect humans and have been associated with hyperproliferative lesions. The recently discovered mouse specific papillomavirus, MmuPV1, provides the opportunity to study papillomavirus infections in vivo in the context of a common laboratory mouse model ( Mus musculus ). To date, a major challenge in the field has been the lack of tools to identify, observe and characterize individually the papillomavirus hosting cells and also trace the progeny of these cells over time. Here, we present the successful generation of an in vivo lineage-tracing model of MmuPV1-harboring cells and their progeny by means of genetic reporter activation. Following the validation of the system both in vitro and in vivo , we used it to provide a proof-of-concept of its utility. Using flow-cytometry analysis, we observed increased proliferation dynamics and decreased MHC-I cell surface expression in MmuPV1-treated tissues which could have implications in tissue regenerative capacity and ability to clear the virus. This model is a novel tool to study the biology of the MmuPV1 host-pathogen interactions.