A central region in the minor capsid protein of papillomaviruses facilitates viral genome tethering and membrane penetration for mitotic nuclear entry

PLoS Pathogens

Samuel K. Campos¹  Mario Schelhaas²  Matthew P. Bronnimann²  Ruth Villalonga-Planells²  Christine M. Calton²  Lilo Greune³  Inci Aydin³  M. Alexander Schmidt³  Kun-Yi Lai⁴  Miriam Becker⁵ 

[1] BIO5 Institute, University of Arizona, Tucson, AZ, USA;Cells in Motion, CiM, Cluster of Excellence EXC, Münster, Germany;Cellular Virology, Institutes of Molecular Virology and Medical Biochemistry, Center for Molecular Biology of Inflammation (ZMBE), University of Münster, Münster, Germany;Department of Immunobiology, University of Arizona, Tucson, AZ, United States of America;Institute of Infectiology, Center for Molecular Biology of Inflammation (ZMBE), University of Münster, Münster, Germany

关键词: HPV-16;    Chromatin;    Viral packaging;    Prometaphase;    Mitosis;    Chromosome structure;    function;    Metaphase;    Point mutation;   

DOI  :  10.1371/journal.ppat.1006308

学科分类：生物科学（综合）

来源: Public Library of Science

【 摘 要 】

Incoming papillomaviruses (PVs) depend on mitotic nuclear envelope breakdown to gain initial access to the nucleus for viral transcription and replication. In our previous work, we hypothesized that the minor capsid protein L2 of PVs tethers the incoming vDNA to mitotic chromosomes to direct them into the nascent nuclei. To re-evaluate how dynamic L2 recruitment to cellular chromosomes occurs specifically during prometaphase, we developed a quantitative, microscopy-based assay for measuring the degree of chromosome recruitment of L2-EGFP. Analyzing various HPV16 L2 truncation-mutants revealed a central chromosome-binding region (CBR) of 147 amino acids that confers binding to mitotic chromosomes. Specific mutations of conserved motifs (IVAL286AAAA, RR302/5AA, and RTR313EEE) within the CBR interfered with chromosomal binding. Moreover, assembly-competent HPV16 containing the chromosome-binding deficient L2(RTR313EEE) or L2(IVAL286AAAA) were inhibited for infection despite their ability to be transported to intracellular compartments. Since vDNA and L2 were not associated with mitotic chromosomes either, the infectivity was likely impaired by a defect in tethering of the vDNA to mitotic chromosomes. However, L2 mutations that abrogated chromatin association also compromised translocation of L2 across membranes of intracellular organelles. Thus, chromatin recruitment of L2 may in itself be a requirement for successful penetration of the limiting membrane thereby linking both processes mechanistically. Furthermore, we demonstrate that the association of L2 with mitotic chromosomes is conserved among the alpha, beta, gamma, and iota genera of Papillomaviridae. However, different binding patterns point to a certain variance amongst the different genera. Overall, our data suggest a common strategy among various PVs, in which a central region of L2 mediates tethering of vDNA to mitotic chromosomes during cell division thereby coordinating membrane translocation and delivery to daughter nuclei.

【 授权许可】

CC BY