# Human papillomavirus entry: late trafficking and establishment of infection

> **NIH NIH R01** · LOUISIANA STATE UNIV HSC SHREVEPORT · 2024 · $444,993

## Abstract

The trans-golgi network (TGN) serves as intermediate target organelle of the cytoplasmic transport during HPV
infectious entry. It has previously been established that nuclear envelope breakdown is required for viral genome
to enter the nucleus. We recently found that viral genome dissociates from TGN in prophase and associates with
microtubules to accumulate at the microtubule-organizing center. At later stages of mitosis (metaphase), viral
genome moves away from the mitotic spindle poles towards chromosomes. Our data point to a switch in the
directionality of microtubule mediated transport from minus end- to plus end-directed during mitosis. Preliminary
inhibitor studies point to dynein and Kif11 as motor proteins involved in the transport. Shift in directionality and
the role of motor proteins for microtubule mediated transport will be further studied in Aim 1. Rather than
egressing from the endocytic compartment in prophase, viral genome is still found in a membrane-bound
vesicular compartment throughout mitotic transport. Viral genome egresses from membrane vesicles after
nuclear envelope reformation. These are paradigm shifting findings, which have recently been confirmed by Day
et al using electron microscopy. It is unclear, how HPV achieves egress from the nuclear transport vesicles. We
hypothesized that HPV utilizes a cellular pathway to dissolve vesicles ending up in the nucleus, whether on
purpose (e.g. viral infection) or accidentally. Indeed, preliminary data suggest that specific isoforms of
phospholipase C, whose knockdown severely impairs HPV16 infection at a stage after nuclear delivery, may be
involved in dissolving the vesicular membrane. The hypothesis will be tested in Aim 2 using knockdown and
knockout approaches combined with differential staining techniques and EM. Release from transport vesicles is
preceded by PML protein recruitment. Recruitment of another component of PML nuclear bodies (NB), Sp100,
is specifically delayed in PML NB assembling around incoming genome. In cells deficient for PML protein, viral
genome is lost and therefore transcriptionally inactive. In Aim 2, we will test our hypothesis that the recruitment
of specific PML isoforms is the underlying reason for delayed recruitment of Sp100 and that HPV-induced PML
NB reorganization is important for transcriptional regulation of the incoming genome. We have recently described
a novel cell culture model that allows efficient infection of primary keratinocytes for investigating the role of PML
NB components in a relevant cell culture model.
Overall, our proposed studies will fill a huge gap in the understanding of microtubule mediated transport during
late HPV intracellular trafficking and will help us unravel the role of PML NB during the immediate early events
of the HPV life cycle essential for establishing infection. Furthermore, the proposal has the potential to uncover
a hitherto unrecognized cellular pathway to dissolve vesicles ending up in the nucleu...

## Key facts

- **NIH application ID:** 10866563
- **Project number:** 5R01AI164683-04
- **Recipient organization:** LOUISIANA STATE UNIV HSC SHREVEPORT
- **Principal Investigator:** ANDREW D YUROCHKO
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $444,993
- **Award type:** 5
- **Project period:** 2021-07-01 → 2026-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10866563

## Citation

> US National Institutes of Health, RePORTER application 10866563, Human papillomavirus entry: late trafficking and establishment of infection (5R01AI164683-04). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10866563. Licensed CC0.

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