Jianxin You, Ph.D.

Office Address:
201C Johnson Pavilion
3610 Hamilton Walk
Philadelphia, PA 19104-6076

TEL 215-573-6781
LAB 215-573-6040
FAX 215-898-9557
jianyou@mail.med.upenn.edu

RESEARCH SUMMARY

Cervical carcinomas are associated with high-risk type human papillomaviruses (HPVs) such as HPV-16 and -18. The important cellular events that caused the HPV-infected cells to develop into invasive tumor do not occur until many years after the initial infection, supporting that persistent infection with high-risk HPVs is required for the progression to invasive carcinoma. Research in our laboratory focuses on understanding the virus-host interactions that allow high-risk HPV to establish and maintain persistent infection in host cells.
Papillomaviruses establish persistent latent infection by maintaining the viral genome as autonomous replicating plasmid (episome) in infected cells. To ensure the faithful partitioning of replicated viral episomes to daughter cells during host cell division, the viral E2 protein tethers the viral episomes to host chromosomes during mitosis. Using the bovine papillomavirus (BPV) as a model system, we have identified the cellular bromodomain protein Brd4 as the anchor for E2/viral episome complex on host mitotic chromosomes. However, how the human papillomaviruses are maintained in host cells during latent infection is less clear.
Our major research goals are: 1) to understand the mechanisms that mediate the persistent maintenance of HPVs in host cells, 2) to identify novel cellular targets of this oncogenic DNA tumor virus and to investigate how they regulate papillomavirus life cycle to achieve viral persistence and malignant progression, and 3) to investigate how dysfunction of important cellular apparatus hijacked by viral pathogen could lead to human diseases. Our research integrates biochemistry, proteomics, cell biology and molecular genetics to study how the molecular interplays between oncogenic DNA tumor viruses and their host targets contribute to tumorigenesis. Knowledge on the nature of this virus-host interaction could facilitate the development of novel therapies for treating high-risk HPV latent infection and associated human cancers.

SELECTED RECENT PUBLICATIONS

You J, Srinivasan V, Denis GV, Harrington Jr WJ, Ballestas ME, Kaye KM, Howley PM. The Kaposi’s Sarcoma-Associated Herpesvirus Latency-Associated Nuclear Antigen interacts with bromodomain protein Brd4 on host mitotic chromosomes. J Virol. 2006; 80:8909-19.

Schweiger MR, You J, Howley PM. Bromodomain protein 4 mediates the papillomavirus E2 transcriptional activation function. J Virol. 2006;80:4276-85.

You J, Schweiger MR, Howley PM. Inhibition of E2 binding to Brd4 enhances viral genome loss and phenotypic reversion of bovine papillomavirus-transformed cells. J Virol. 2005;79:14956-61.

You J, Croyle JL, Nishimura A, Ozato K, Howley PM. Interaction of the bovine papillomavirus E2 protein with Brd4 tethers the viral DNA to host mitotic chromosomes. Cell. 2004;117:349-60.