Translocation of the papillomavirus L2/vDNA complex across the limiting membrane requires the onset of mitosis

PLoS Pathogens

Christine M. Calton¹  Samuel K. Campos¹  Janice A. Chapman¹  Shuaizhi Li²  Ricardo A. Bernal³  Sudheer K. Molugu³  Matthew P. Bronnimann⁴  Ariana R. Manson⁵  Marcela Suarez-Berumen⁵  Tatum R. Williamson⁵ 

[1] BIO5 Institute, University of Arizona, Tucson, Arizona, United States of America;Department of Cellular & Molecular Medicine, University of Arizona, Tucson, Arizona, United States of America;Department of Chemistry, University of Texas at El Paso, El Paso, Texas, United States of America;Department of Immunobiology, University of Arizona, Tucson, Arizona, United States of America;Department of Molecular & Cellular Biology, University of Arizona, Tucson, Arizona, United States of America

关键词: Mitosis;    Biotinylation;    Viral packaging;    Cell cycle inhibitors;    Cell cycle;    cell division;    Chromatin;    Small interfering RNAs;    Membrane trafficking;   

DOI  :  10.1371/journal.ppat.1006200

学科分类：生物科学（综合）

来源: Public Library of Science

【 摘 要 】

The human papillomavirus type 16 (HPV16) L2 protein acts as a chaperone to ensure that the viral genome (vDNA) traffics from endosomes to the trans-Golgi network (TGN) and eventually the nucleus, where HPV replication occurs. En route to the nucleus, the L2/vDNA complex must translocate across limiting intracellular membranes. The details of this critical process remain poorly characterized. We have developed a system based on subcellular compartmentalization of the enzyme BirA and its cognate substrate to detect membrane translocation of L2-BirA from incoming virions. We find that L2 translocation requires transport to the TGN and is strictly dependent on entry into mitosis, coinciding with mitotic entry in synchronized cells. Cell cycle arrest causes retention of L2/vDNA at the TGN; only release and progression past G2/M enables translocation across the limiting membrane and subsequent infection. Microscopy of EdU-labeled vDNA reveals a rapid and dramatic shift in vDNA localization during early mitosis. At late G2/early prophase vDNA egresses from the TGN to a pericentriolar location, accumulating there through prometaphase where it begins to associate with condensed chromosomes. By metaphase and throughout anaphase the vDNA is seen bound to the mitotic chromosomes, ensuring distribution into both daughter nuclei. Mutations in a newly defined chromatin binding region of L2 potently blocked translocation, suggesting that translocation is dependent on chromatin binding during prometaphase. This represents the first time a virus has been shown to functionally couple the penetration of limiting membranes to cellular mitosis, explaining in part the tropism of HPV for mitotic basal keratinocytes.

【 授权许可】

CC BY