Human Papillomavirus Major Capsid Protein L1 Remains Associated with the Incoming Viral Genome throughout the Entry Process.

During infectious entry, acidification within the endosome triggers uncoating of the human papillomavirus (HPV) capsid, whereupon host cyclophilins facilitate the release of most of the major capsid protein, L1, from the minor capsid protein L2 and the viral genome. The L2/DNA complex traffics to the -Golgi network (TGN). After the onset of mitosis, HPV-harboring transport vesicles bud from the TGN, followed by association with mitotic chromosomes.

Incoming human papillomavirus 16 genome is lost in PML protein-deficient HaCaT keratinocytes.

Unlabelled: Human papillomaviruses (HPVs) target promyelocytic leukemia (PML) nuclear bodies (NBs) during infectious entry and PML protein is important for efficient transcription of incoming viral genome. However, the transcriptional down regulation was shown to be promoter-independent in that heterologous promoters delivered by papillomavirus particles were also affected. To further investigate the role of PML protein in HPV entry, we used small hairpin RNA to knockdown PML protein in HaCaT keratinocytes.

Topography of the Human Papillomavirus Minor Capsid Protein L2 during Vesicular Trafficking of Infectious Entry.

Unlabelled: The human papillomavirus (HPV) capsid is composed of the major capsid protein L1 and the minor capsid protein L2. During entry, the HPV capsid undergoes numerous conformational changes that result in endosomal uptake and subsequent trafficking of the L2 protein in complex with the viral DNA to the trans-Golgi network. To facilitate this transport, the L2 protein harbors a number of putative motifs that, if capable of direct interaction, would interact with cytosolic host cell factors.