Preferential recruitment of PML isoform II by incoming HPV16 genome transport vesicles facilitates early stage of infection

The interplay between promyelocytic leukemia nuclear bodies (PML NBs) and viral infections is complex and multifaceted, with viruses often engaging in a delicate balance of exploitation and evasion of host immune responses. It is well-established that incoming human papillomavirus (HPV) virions associate with PML NBs; however, the mechanism by which HPV targets PML NBs to facilitate early transcription and replication remains elusive. We have shown that HPV genomes are delivered to the nucleus inside membrane-bound vesicles during mitosis and that PML proteins are recruited to HPV-harboring nuclear vesicles prior to egress. Herein, we demonstrate that the PML isoform II (PMLII), but not other PML isoforms, is selectively attracted to incoming HPV still residing in transport vesicles. Using individual PML NB isoform and HPV16 minor protein, L2, over-expression experiments in HeLa cells, we conclude that PML II binds to the lipids of the HPV harbouring membrane-bound vesicles rather than L2. This is in line with previous observations that PML II is the only isoform binding to lipid droplets in the nucleus. We observed that the association of PML NBs with the HPV16 viral genome was transient and lost over time. We also found that nuclear Phospholipase C β4 and γ1 colocalize with PML II-L1 complexes in infected cells. Our data support a model in which PML II contributes to the establishment of early HPV16 infection by organizing host lipid regulatory factors at incoming viral transport vesicles.