Alison McBride, Ph.D.
Chief, DNA Tumor Virus Section, LVD
Papillomaviruses are small DNA viruses that persistently infect and replicate in stratified cutaneous and mucosal epithelia. Each papillomavirus type is species-specific and has a tropism for certain types of epithelia. In most cases, the resulting papillomas are benign, but infection with certain papillomavirus types can lead to the development of carcinomas.
The basal cells of stratified epithelia constantly divide to replenish the overlying differentiated cell layers. The viral DNA replicates and is maintained in these dividing basal cells as low copy, extrachromosomal circular DNA molecules. Viral genome amplification and synthesis of capsid proteins occurs only in the upper layers of the epithelium. Papillomavirus infections are usually long-lived, and the dividing basal cells provide a reservoir of infected cells for the overlying virus producing tissue. This strategy requires that the papillomaviruses have a faithful and robust mechanism to replicate and retain their extrachromosomal genomes in the nuclei of dividing cells.
Papillomaviruses have exploited interactions between virus and host chromatin at many stages of the viral life cycle. Viral DNA is targeted to beneficial regions of the host nucleus to ensure that the genomes are transcriptionally active and are not eliminated from the cell or repressed in heterochromatin. Viral genomes are tethered to specific regions of host mitotic chromosomes to efficiently partition the viral genomes to daughter cells. Viral DNA replication also initiates at specific regions of host chromatin, where the viral E1 and E2 proteins initiate a DNA damage response that recruits cellular DNA repair proteins to viral replication foci for efficient viral DNA synthesis.
The papillomavirus genomes are tethered to host chromatin by the viral E2 protein. The E2 protein binds specifically to repeated DNA binding motifs in the viral genomes and links them to the host chromosomes via protein-protein interactions. This ensures that viral genomes remain in the nucleus and are partitioned to daughter cells in approximately equal numbers. There are variations in the association of different papillomavirus E2 proteins with mitotic chromosomes, and different papillomaviruses have evolved to bind to different chromosomal targets to partition their genomes. Other persistent DNA viruses, such as the gamma herpesviruses, have adopted a similar strategy to retain and partition their genomes in dividing cells.
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Dr. McBride received a B.Sc.(with Honors) in molecular biology from the University of Glasgow, Scotland, and a Ph.D. in biochemistry from the Imperial Cancer Research Fund and Imperial College, London, studying Epstein-Barr virus. She began working on human and other papillomaviruses as a postdoctoral fellow in the National Cancer Institute and joined NIAID in 1994. She became a senior investigator in the Laboratory of Viral Diseases in 2000.
Moon-Kyoo Jang, Staff ScientistKoenraad van Doorslaer, Postdoctoral FellowCaleb McKinney, Postdoctoral FellowWesley Stepp, Predoctoral FellowKatharine Dolley, Post-baccalaureate FellowDan Chen, Biologist
Jang MK, Shen K, McBride AA. Papillomavirus genomes associate with BRD4 to replicate at fragile sites in the host genome. PLoS Pathog. 2014 May 15;10(5):e1004117.
Chapman S, McDermott DH, Shen K, Jang MK, McBride AA. The effect of Rho kinase inhibition on long-term keratinocyte proliferation is rapid and conditional. Stem Cell Res Ther. 2014 Apr 28;5(2):60.
Sakakibara N, Chen D, Jang MK, Kang DW, Luecke HF, Wu SY, Chiang CM, McBride AA. Brd4 is displaced from HPV replication factories as they expand and amplify viral DNA. PLoS Pathog. 2013;9(11):e1003777.
Stepp WH, Meyers JM, McBride AA. Sp100 provides intrinsic immunity against human papillomavirus infection. MBio. 2013 Nov 5;4(6):e00845-13.
Sakakibara N, Chen D, McBride AA. Papillomaviruses use recombination-dependent replication to vegetatively amplify their genomes in differentiated cells. PLoS Pathog. 2013;9(7):e1003321.
Van Doorslaer K, Tan Q, Xirasagar S, Bandaru S, Gopalan V, Mohamoud Y, Huyen Y, McBride AA. The Papillomavirus Episteme: a central resource for papillomavirus sequence data and analysis. Nucleic Acids Res. 2013 Jan;41(Database issue):D571-8.
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In collaboration with the NIAID Office of Cyber Infrastructure and Computational Biology Bioinformatics and the Computational Biosciences Branch, we established the PapillomaVirus Episteme (PaVE) to provide information and bioinformatics resources to the scientific community for research on the Papillomaviridae. The goal of PaVE is to provide an HPV sequence database and tools that will accelerate scientific progress and ultimately our understanding, detection, diagnosis, and treatment of diseases caused by papillomaviruses. Find out more about the PaVE animal papillomavirus and human papillomavirus (HPV) sequence database.
Last Updated September 12, 2012
Last Reviewed September 12, 2012