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.

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 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 Mitotic Kinesin-Like Protein 2 Binds and Colocalizes with Papillomavirus E2 during Mitosis

2006 ◽  
Vol 81 (4) ◽  
pp. 1736-1745 ◽  
Author(s):  
Ting Yu ◽  
Yu-Cai Peng ◽  
Elliot J. Androphy
Keyword(s):  
Cell Cycle ◽  
Mitotic Spindle ◽  
Chromatin Immunoprecipitation ◽  
Viral Genome ◽  
Motor Protein ◽  
Dna Binding Protein ◽  
E2 Protein ◽  
Viral Genomes ◽  
Daughter Cells ◽  
Transcription And Replication

ABSTRACT MKlp2 is a kinesin-like motor protein of the central mitotic spindle required for completion of cytokinesis. Papillomavirus E2 is a sequence specific DNA binding protein that regulates viral transcription and replication and is responsible for partitioning viral episomes into daughter cells during cell division. We demonstrate that MKlp2 specifically associates with the E2 protein during mitosis. Using chromatin immunoprecipitation, we show viral genomes are in complex with MKlp2 only within this stage of cell cycle. By immunofluorescence, a subpopulation of papillomavirus E2 colocalizes with MKlp2 in the midbody/midplate during late mitosis. We conclude that during specific stages of mitosis, the papillomavirus E2 protein binds to MKlp2, and infer that association with this motor protein ensures viral genome partitioning during cytokinesis.

scholarly journals Kaposi’s Sarcoma-Associated Herpesvirus LANA-Adjacent Regions with Distinct Functions in Episome Segregation or Maintenance

2019 ◽  
Vol 93 (6) ◽  
Author(s):  
Franceline Juillard ◽  
Erika De León Vázquez ◽  
Min Tan ◽  
Shijun Li ◽  
Kenneth M. Kaye
Keyword(s):  
Dna Replication ◽  
Daughter Cell ◽  
Upstream Sequence ◽  
Cell Nuclei ◽  
Mitotic Chromosomes ◽  
Repeat Elements ◽  
Viral Genomes ◽  
Daughter Cells ◽  
Internal Repeat ◽  
Carboxy Terminal

ABSTRACTKaposi’s sarcoma-associated herpesvirus (KSHV) latency-associated nuclear antigen (LANA) is a 1,162-amino-acid protein that mediates episome persistence of viral genomes. LANA binds the KSHV terminal-repeat (TR) sequence through its carboxy-terminal domain to mediate DNA replication. LANA simultaneously binds mitotic chromosomes and TR DNA to segregate virus genomes to daughter cell nuclei. Amino-terminal LANA attaches to chromosomes by binding histones H2A/H2B, and carboxy-terminal LANA contributes to mitotic-chromosome binding. Although amino- and carboxy-terminal LANA are essential for episome persistence, they are not sufficient, since deletion of all internal LANA sequence renders LANA highly deficient for episome maintenance. Internal LANA sequence upstream of the internal repeat elements contributes to episome segregation and persistence. Here, we investigate this region with a panel of LANA deletion mutants. Mutants retained the ability to associate with mitotic chromosomes and bind TR DNA. In contrast to prior results, deletion of most of this sequence did not reduce LANA’s ability to mediate DNA replication. Deletions of upstream sequence within the region compromised segregation of TR DNA to daughter cells, as assessed by retention of green fluorescent protein (GFP) expression from a replication-deficient TR plasmid. However, deletion of this upstream sequence did not reduce episome maintenance. In contrast, deletions that included an 80-amino-acid sequence immediately downstream resulted in highly deficient episome persistence. LANA with this downstream sequence deleted maintained the ability to replicate and segregate TR DNA, suggesting a unique role for the residues. Therefore, this work identifies adjacent LANA regions with distinct roles in episome segregation and persistence.IMPORTANCEKSHV LANA mediates episomal persistence of viral genomes. LANA binds the KSHV terminal-repeat (TR) sequence to mediate DNA replication and tethers KSHV DNA to mitotic chromosomes to segregate genomes to daughter cell nuclei. Here, we investigate LANA sequence upstream of the internal repeat elements that contributes to episome segregation and persistence. Mutants with deletions within this sequence maintained the ability to bind mitotic chromosomes or bind and replicate TR DNA. Deletion of upstream sequence within the region reduced segregation of TR DNA to daughter cells, but not episome maintenance. In contrast, mutants with deletions of 80 amino acids immediately downstream were highly deficient for episome persistence yet maintained the ability to replicate and segregate TR DNA, the two principal components of episome persistence, suggesting another role for the residues. In summary, this work identifies adjacent LANA sequence with distinct roles in episome segregation and persistence.

scholarly journals Targeting mitotic chromosomes: a conserved mechanism to ensure viral genome persistence

2009 ◽  
Vol 276 (1662) ◽  
pp. 1535-1544 ◽  
Author(s):  
Katherine M Feeney ◽  
Joanna L Parish
Keyword(s):  
Host Cell ◽  
Genetic Material ◽  
Membrane Integrity ◽  
Mitotic Chromosomes ◽  
Nuclear Retention ◽  
Viral Genomes ◽  
Daughter Cells ◽  
Dna Damage Checkpoints ◽  
Low Copy Number ◽  
Dividing Cells

Viruses that maintain their genomes as extrachromosomal circular DNA molecules and establish infection in actively dividing cells must ensure retention of their genomes within the nuclear envelope in order to prevent genome loss. The loss of nuclear membrane integrity during mitosis dictates that paired host cell chromosomes are captured and organized by the mitotic spindle apparatus before segregation to daughter cells. This prevents inaccurate chromosomal segregation and loss of genetic material. A similar mechanism may also exist for the nuclear retention of extrachromosomal viral genomes or episomes during mitosis, particularly for genomes maintained at a low copy number in latent infections. It has been heavily debated whether such a mechanism exists and to what extent this mechanism is conserved among diverse viruses. Research over the last two decades has provided a wealth of information regarding the mechanisms by which specific tumour viruses evade mitotic and DNA damage checkpoints. Here, we discuss the similarities and differences in how specific viruses tether episomal genomes to host cell chromosomes during mitosis to ensure long-term persistence.

scholarly journals Different Modes of Human Papillomavirus DNA Replication during Maintenance

2006 ◽  
Vol 80 (9) ◽  
pp. 4431-4439 ◽  
Author(s):  
Ralf Hoffmann ◽  
Bernhard Hirt ◽  
Viviane Bechtold ◽  
Peter Beard ◽  
Kenneth Raj
Keyword(s):  
Human Papillomavirus ◽  
Dna Replication ◽  
S Phase ◽  
Basal Cells ◽  
Random Choice ◽  
Proliferating Cells ◽  
Hpv Dna ◽  
Viral Genomes ◽  
Viral Dnas ◽  
Keratinocyte Cell

ABSTRACT Human papillomavirus (HPV) begins its life cycle by infecting the basal cells of the epithelium. Within these proliferating cells, the viral genomes are replicated, maintained, and passed on to the daughter cells. Using HPV episome-containing cell lines that were derived from naturally infected cervical tissues, we investigated the mode by which the viral DNAs replicate in these cells. We observed that, whereas HPV16 DNA replicated in an ordered once-per-S-phase manner in W12 cells, HPV31 DNA replicated via a random-choice mechanism in CIN612 cells. However, when HPV16 and HPV31 DNAs were separately introduced into an alternate keratinocyte cell line NIKS, they both replicated randomly. This indicates that HPV DNA is inherently capable of replicating by either random-choice or once-per-S-phase mechanisms and that the mode of HPV DNA replication is dependent on the cells that harbor the viral episome. High expression of the viral replication protein E1 in W12 cells converted HPV16 DNA replication to random-choice replication and, as such, it appears that the mode of HPV DNA replication in proliferating cells is dependent on the presence or the increased level of this protein in the host cell. The implications of these observations on maintenance, latency, and persistence are discussed.

scholarly journals Effects of altering histone posttranslational modifications on mitotic chromosome structure and mechanics

2019 ◽  
Vol 30 (7) ◽  
pp. 820-827 ◽  
Author(s):  
Ronald Biggs ◽  
Patrick Z. Liu ◽  
Andrew D. Stephens ◽  
John F. Marko
Keyword(s):  
Posttranslational Modifications ◽  
Large Scale ◽  
Mitotic Chromosome ◽  
Chromosome Doubling ◽  
Chromosome Length ◽  
Force Measurements ◽  
Mitotic Chromosomes ◽  
Daughter Cells ◽  
Histone Ptms ◽  
Canonical Histone

During cell division, chromatin is compacted into mitotic chromosomes to aid faithful segregation of the genome between two daughter cells. Posttranslational modifications (PTMs) of histones alter compaction of interphase chromatin, but it remains poorly understood how these modifications affect mitotic chromosome stiffness and structure. Using micropipette-based force measurements and epigenetic drugs, we probed the influence of canonical histone PTMs that dictate interphase euchromatin (acetylation) and heterochromatin (methylation) on mitotic chromosome stiffness. By measuring chromosome doubling force (the force required to double chromosome length), we find that histone methylation, but not acetylation, contributes to mitotic structure and stiffness. We discuss our findings in the context of chromatin gel modeling of the large-scale organization of mitotic chromosomes.

scholarly journals The human papillomavirus 16 E2 protein is stabilised in S phase

Virology ◽  
2009 ◽  
Vol 394 (2) ◽  
pp. 194-199 ◽  
Author(s):  
Cecilia Johansson ◽  
Sheila V. Graham ◽  
Edward S. Dornan ◽  
Iain M. Morgan
Keyword(s):  
Human Papillomavirus ◽  
S Phase ◽  
E2 Protein ◽  
Human Papillomavirus 16

scholarly journals Interaction of Bovine Papillomavirus E2 Protein with Brd4 Stabilizes Its Association with Chromatin

2005 ◽  
Vol 79 (14) ◽  
pp. 8920-8932 ◽  
Author(s):  
Maria G. McPhillips ◽  
Keiko Ozato ◽  
Alison A. McBride
Keyword(s):  
Cell Types ◽  
Bovine Papillomavirus ◽  
Chromosomal Protein ◽  
Transactivation Domain ◽  
Mitotic Chromosomes ◽  
E2 Protein ◽  
Viral Genomes ◽  
Protein Protein Interaction ◽  
Binding Function ◽  
Interphase Cells

ABSTRACT The bovine papillomavirus E2 protein maintains and segregates the viral extrachromosomal genomes by tethering them to cellular mitotic chromosomes. E2 interacts with a cellular bromodomain protein, Brd4, to mediate the segregation of viral genomes into daughter cells. Brd4 binds acetylated histones and has been observed to diffusely coat mitotic chromosomes in several cell types. In this study, we show that in mitotic C127 cells, Brd4 diffusely coated the condensed chromosomes. However, in the presence of the E2 protein, E2 and Brd4 colocalized in punctate dots that were randomly distributed over the chromosomes. A similar pattern of E2 and Brd4 colocalization on mitotic chromosomes was observed in CV-1 cells, whereas only a faint chromosomal coating of Brd4 was detected in the absence of the E2 protein. Therefore, the viral E2 protein relocalizes and/or stabilizes the association of Brd4 with chromosomes in mitotic cells. The colocalization of E2 and Brd4 was also observed in interphase cells, indicating that this protein-protein interaction persists throughout the cell cycle. The interaction of E2 with Brd4 greatly stabilized the association of Brd4 with interphase chromatin. In both mitotic and interphase cells, this stabilization required a transcriptionally competent transactivation domain, but not the DNA binding function of the E2 protein. Thus, the E2 protein modulates the chromatin association of Brd4 during both interphase and mitosis. This study demonstrates that the segregation of papillomavirus genomes is not simply due to the passive hitchhiking of the E2/genome complex with a convenient cellular chromosomal protein.

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