scholarly journals Dynamic Localization of the Human Papillomavirus Type 11 Origin Binding Protein E2 through Mitosis While in Association with the Spindle Apparatus

2006 ◽  
Vol 80 (10) ◽  
pp. 4792-4800 ◽  
Author(s):  
Luan D. Dao ◽  
Aaron Duffy ◽  
Brian A. Van Tine ◽  
Shwu-Yuan Wu ◽  
Cheng-Ming Chiang ◽  
...  
Keyword(s):  
Human Papillomavirus ◽  
Binding Protein ◽  
Cellular Protein ◽  
Bovine Papillomavirus ◽  
Mitotic Spindles ◽  
Mitotic Chromosomes ◽  
Mitotic Apparatus ◽  
Viral Origin ◽  
E2 Protein ◽  
Origin Binding Protein

ABSTRACT Papillomaviral DNA replicates as extrachromosomal plasmids in squamous epithelium. Viral DNA must segregate equitably into daughter cells to persist in dividing basal/parabasal cells. We have previously reported that the viral origin binding protein E2 of human papillomavirus types 11 (HPV-11), 16, and 18 colocalized with the mitotic spindles. In this study, we show the localization of the HPV-11 E2 protein to be dynamic. It colocalized with the mitotic spindles during prophase and metaphase. At anaphase, it began to migrate to the central spindle microtubules, where it remained through telophase and cytokinesis. It was additionally observed in the midbody at cytokinesis. A peptide spanning residues 285 to 308 in the carboxyl-terminal domain of HPV-11 E2 (E2C) is necessary and sufficient to confer localization on the mitotic spindles. This region is conserved in HPV-11, -16, and -18 and bovine papillomavirus type 4 (BPV-4) E2 and is also required for the respective E2C to colocalize with the mitotic spindles. The E2 protein of bovine papillomavirus type 1 is tethered to the mitotic chromosomes via the cellular protein Brd4. However, the HPV-11 E2 protein did not associate with Brd4 during mitosis. Lastly, a chimeric BPV-1 E2C containing the spindle localization domain from HPV-11 E2C gained the ability to localize to the mitotic spindles, whereas the reciprocal chimera lost the ability. We conclude that this region of HPV E2C is critical for localization with the mitotic apparatus, enabling the HPV DNA to sustain persistent infections.

scholarly journals The Human Papillomavirus Type 8 E2 Tethering Protein Targets the Ribosomal DNA Loci of Host Mitotic Chromosomes

2008 ◽  
Vol 83 (2) ◽  
pp. 640-650 ◽  
Author(s):  
Atasi Poddar ◽  
Shawna C. Reed ◽  
Maria G. McPhillips ◽  
Jonathan E. Spindler ◽  
Alison A. McBride
Keyword(s):  
Human Papillomavirus ◽  
Ribosomal Dna ◽  
Cellular Protein ◽  
Bovine Papillomavirus ◽  
Mitotic Chromosomes ◽  
Protein Targets ◽  
E2 Protein ◽  
Viral Genomes ◽  
Wide Range ◽  
Polymerase I

ABSTRACT For many papillomaviruses, the viral protein E2 tethers the viral genome to the host mitotic chromosomes to ensure persistent, long-term maintenance of the genome during cell division. Our previous studies of E2 proteins from different genera of papillomaviruses have shown that they bind to different regions of the host chromosomes during mitosis. For example, bovine papillomavirus type 1 (BPV-1) E2 binds to all chromosomes as small speckles in complex with the cellular protein Brd4. In contrast, the human papillomavirus type 8 (HPV-8) E2 protein binds as large speckles at the pericentromeric regions of chromosomes. Here we show that these speckles do not contain Brd4, and unlike that of BPV-1, the N-terminal Brd4-interacting domain of HPV-8 E2 is not required for chromosome binding. In contrast to BPV-1 E2, the HPV-8 E2 protein targets the short arms of acrocentric mitotic chromosomes. Furthermore, the E2 protein interacts with the repeated ribosomal DNA genes found in this location and colocalizes with UBF, the RNA polymerase I transcription factor. Therefore, HPV-8 E2 genome tethering occurs by a Brd4-independent mechanism through a novel interaction with specific regions of mitotic chromosomes. Thus, a wide range of viruses have adopted the strategy of linking their genomes to host chromosomes, but individual viruses use different chromosomal targets. Characterization of these targets will enable the development of antiviral therapies to eliminate the viral genomes from infected cells.

scholarly journals Human papillomavirus (HPV) origin-binding protein associates with mitotic spindles to enable viral DNA partitioning

2004 ◽  
Vol 101 (12) ◽  
pp. 4030-4035 ◽  
Author(s):  
B. A. Van Tine ◽  
L. D. Dao ◽  
S.-Y. Wu ◽  
T. M. Sonbuchner ◽  
B. Y. Lin ◽  
...  
Keyword(s):  
Human Papillomavirus ◽  
Binding Protein ◽  
Mitotic Spindles ◽  
Viral Dna ◽  
Origin Binding Protein ◽  
Dna Partitioning

scholarly journals Association of Bovine Papillomavirus E2 Protein with Nuclear Structures In Vivo

2005 ◽  
Vol 79 (16) ◽  
pp. 10528-10539 ◽  
Author(s):  
Reet Kurg ◽  
Kristiina Sild ◽  
Aigi Ilves ◽  
Mari Sepp ◽  
Mart Ustav
Keyword(s):  
Cellular Protein ◽  
Micrococcal Nuclease ◽  
Viral Gene ◽  
Genome Replication ◽  
Bovine Papillomavirus ◽  
Transactivation Domain ◽  
Proliferating Cells ◽  
E2 Protein ◽  
Nuclear Structures

ABSTRACT Papillomaviruses are small DNA viruses which have the capacity to establish a persistent infection in mammalian epithelial cells. The papillomavirus E2 protein is a central coordinator of viral gene expression, genome replication, and maintenance. We have investigated the distribution of bovine papillomavirus E2 protein in nuclei of proliferating cells and found that E2 is associated with cellular chromatin. This distribution does not change during the entire cell cycle. The N-terminal transactivation domain, but not the C-terminal DNA-binding domain, of the E2 protein is responsible for this association. The majority of the full-length E2 protein can only be detected in chromatin-enriched fractions but not as a free protein in the nucleus. Limited micrococcal nuclease digestion revealed that the E2 protein partitioned to different chromatin regions. A fraction of the E2 protein was located at nuclear sites that are resistant against nuclease attack, whereas the remaining E2 resided on compact chromatin accessible to micrococcal nuclease. These data suggest that there are two pools of E2 in the cell nucleus: one that localizes on transcriptionally inactive compact chromatin and the other, which compartmentalizes to transcriptionally active nuclear structures of the cell. Our data also suggest that E2 associates with chromatin through cellular protein(s), which in turn is released from chromatin at 0.4 M salt.

scholarly journals Dimerization of the Papillomavirus E2 Protein Is Required for Efficient Mitotic Chromosome Association and Brd4 Binding

2008 ◽  
Vol 82 (15) ◽  
pp. 7298-7305 ◽  
Author(s):  
Juan Cardenas-Mora ◽  
Jonathan E. Spindler ◽  
Moon Kyoo Jang ◽  
Alison A. McBride
Keyword(s):  
Dna Binding ◽  
Fluorescent Protein ◽  
Binding Domain ◽  
Bovine Papillomavirus ◽  
Dna Binding Domain ◽  
Transactivation Domain ◽  
Mitotic Chromosomes ◽  
Dimerization Domain ◽  
E2 Protein ◽  
Binding Function

ABSTRACT The E2 proteins of several papillomaviruses link the viral genome to mitotic chromosomes to ensure retention and the efficient partitioning of genomes into daughter cells following cell division. Bovine papillomavirus type 1 E2 binds to chromosomes in a complex with Brd4, a cellular bromodomain protein. Interaction with Brd4 is also important for E2-mediated transcriptional regulation. The transactivation domain of E2 is crucial for interaction with the Brd4 protein; proteins lacking or mutated in this domain do not interact with Brd4. However, we found that the C-terminal DNA binding/dimerization domain of E2 is also required for efficient binding to Brd4. Mutations that eliminated the DNA binding function of E2 had no effect on the ability of E2 to interact with Brd4, but an E2 protein with a mutation that disrupted C-terminal dimerization bound Brd4 with greatly reduced efficiency. Furthermore, E2 proteins in which the C-terminal domains were replaced with the dimeric DNA binding domain of EBNA-1 or Gal4 bound efficiently to the Brd4 protein, but the replacement of the E2 C-terminal domain with a monomeric red fluorescent protein did not rescue efficient Brd4 binding. Thus, E2 bound to Brd4 most efficiently as a dimer. To prove this finding further, the E2 DNA binding domain was replaced with an FKBP12-derived domain in which dimerization was regulated by a bivalent ligand. This fusion protein bound Brd4 efficiently only in the presence of the ligand, confirming that a dimer of E2 was required. Correspondingly, E2 proteins that could dimerize were able to bind to mitotic chromosomes much more efficiently than monomeric E2 polypeptides.

scholarly journals Interaction of the Bovine Papillomavirus E2 Protein with Brd4 Tethers the Viral DNA to Host Mitotic Chromosomes

Cell ◽  
2004 ◽  
Vol 117 (3) ◽  
pp. 349-360 ◽  
Author(s):  
Jianxin You ◽  
Jennie L Croyle ◽  
Akiko Nishimura ◽  
Keiko Ozato ◽  
Peter M Howley
Keyword(s):  
Bovine Papillomavirus ◽  
Mitotic Chromosomes ◽  
Viral Dna ◽  
E2 Protein

scholarly journals Chaperone Proteins Abrogate Inhibition of the Human Papillomavirus (HPV) E1 Replicative Helicase by the HPV E2 Protein

2002 ◽  
Vol 22 (18) ◽  
pp. 6592-6604 ◽  
Author(s):  
Biing Yuan Lin ◽  
Alexander M. Makhov ◽  
Jack D. Griffith ◽  
Thomas R. Broker ◽  
Louise T. Chow
Keyword(s):  
Human Papillomavirus ◽  
Topoisomerase I ◽  
Atp Binding ◽  
Dna Unwinding ◽  
Chaperone Proteins ◽  
Viral Origin ◽  
Replicative Helicase ◽  
E2 Protein ◽  
Hpv Dna ◽  
Atp Binding Site

ABSTRACT Human papillomavirus (HPV) DNA replication requires the viral origin recognition protein E2 and the presumptive viral replicative helicase E1. We now report for the first time efficient DNA unwinding by a purified HPV E1 protein. Unwinding depends on a supercoiled DNA substrate, topoisomerase I, single-stranded-DNA-binding protein, and ATP, but not an origin. Electron microscopy revealed completely unwound molecules. Intermediates contained two single-stranded loops emanating from a single protein complex, suggesting a bidirectional E1 helicase which translocated the flanking DNA in an inward direction. We showed that E2 protein partially inhibited DNA unwinding and that Hsp70 or Hsp40, which we reported previously to stimulate HPV-11 E1 binding to the origin and promote dihexameric E1 formation, apparently displaced E2 and abolished inhibition. Neither E2 nor chaperone proteins were detected in unwinding complexes. These results suggest that chaperones play important roles in the assembly and activation of a replicative helicase in higher eukaryotes. An E1 mutation in the ATP binding site caused deficient binding and unwinding of origin DNA, indicating the importance of ATP binding in efficient helicase assembly on the origin.

scholarly journals Phosphorylation Regulates Binding of the Human Papillomavirus Type 8 E2 Protein to Host Chromosomes

2012 ◽  
Vol 86 (18) ◽  
pp. 10047-10058 ◽  
Author(s):  
Vandana Sekhar ◽  
Alison A. McBride
Keyword(s):  
Human Papillomavirus ◽  
Posttranslational Modifications ◽  
S Phase ◽  
Chromatin Binding ◽  
Genome Maintenance ◽  
Mitotic Chromosomes ◽  
E2 Protein ◽  
Viral Genomes ◽  
Daughter Cells ◽  
Host Nucleus

The papillomavirus E2 proteins are indispensable for the viral life cycle, and their functions are subject to tight regulation. The E2 proteins undergo posttranslational modifications that regulate their properties and roles in viral transcription, replication, and genome maintenance. During persistent infection, the E2 proteins from many papillomaviruses act as molecular bridges that tether the viral genomes to host chromosomes to retain them within the host nucleus and to partition them to daughter cells. The betapapillomavirus E2 proteins bind to pericentromeric regions of host mitotic chromosomes, including the ribosomal DNA loci. We recently reported that two residues (arginine 250 and serine 253) within the chromosome binding region of the human papillomavirus type 8 (HPV8) E2 protein are required for this binding. In this study, we show that serine 253 is phosphorylated, most likely by protein kinase A, and this modulates the interaction of the E2 protein with cellular chromatin. Furthermore, we show that this phosphorylation occurs in S phase, increases the half-life of the E2 protein, and promotes chromatin binding from S phase through mitosis.

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