Regulation of KSHV Latency

Summary

Principal Investigator: Paul M Lieberman
Abstract: DESCRIPTION (provided by applicant): KSHV is the causative agent of Kaposi's sarcoma (KS) that occurs most frequently and severely in HIV-AIDS. KSHV has also been implicated in several lymphoid disorders, including pleural effusion lymphoma (PEL) and Castleman's disease. Long-term latent infection in B-lymphocytes and persistent infection in endothelial cells is thought to be a major driving force for KSHV-associated pathogenesis. Latent infection is characterized by the transcription of several viral genes associated with viral genome stability and host-cell survival. The major latency transcript is a multicistronic message that consists of the LANA, vCyclin, and vFLIP genes, which can be alternatively spliced to generate the viral microRNAs (vmiRNAs) and Kaposin genes. The latency transcriptional control is also responsible for the regulation of the vGPCR gene, which has been implicated in KS pathogenesis. Proper regulation of these viral transcripts is critical for viral genome persistence during latency and for pathogenesis in KSHV infected lesions. Our preliminary data indicates that this region of the viral chromosome is protected from epigenetic silencing by the chromatin insulator protein CTCF and colocalization with cohesin subunits (e.g. SMC1, SMC3, Rad21). In addition, changes in CTCF-cohesin interactions contribute to the cell cycle activation of vGPCR in latently infected PEL cells. We have also found that these CTCF sites in the latency control region are important for the programming of RNA polymerase II elongation and mRNA processing. In Aim 1, we will determine how the CTCF-cohesin complex contributes to the regulation of latency transcription, and protects the major latency control region from epigenetic silencing. We have also found that viral encoded miRNAs contribute to the epigenetic programming of the viral chromosome during latency. We propose in Aim 2 of this proposal to determine whether CTCF-cohesin complex regulates vmiRNA expression, and additionally, whether vmiRNAs coregulate the function of CTCF- cohesins in regulating the epigenetic state of the latent viral chromosome. Finally, we propose to investigate the mechanism of a small molecule inhibitor that selectively deregulates KSHV latency transcription. Glychyrrizic acid (GA) is a bioactive natural product derived from licorice that selectively inhibits KSHV positive PEL cell proliferation. We have found that GA deregulates RNA polymerase II interactions with the CTCF- cohesin complex at the LANA 5'UTR. We have used chemical affinity to identify candidate target molecules of GA. In Aim 3, we propose to further characterize the mechanism of GA deregulation of LANA transcription and its potential targeting of the CTCF-cohesin complex. Together, these aims focus on a novel mechanism of gene regulation that maintains latency gene expression during latency, restricts the pathogenic expression of vGPCR, and may serve as a potential target for small molecule intervention in KSHV-associated disease. PUBLIC HEALTH RELEVANCE: Human herpesvirus 8 (HHV8), more commonly referred to as Kaposi's Sarcoma (KS)-Associated Herpesvirus (KSHV) is the etiological agent of HIV-associated and endemic forms of KS. KSHV has also been linked to two other lymphoproliferative disorders, primary effusion lymphoma (PELs) and multicentric Castleman's disease. Additional diseases may also be associated with KSHV, including autoimmune disorders like multiple sclerosis and system lupus erythematosis. In all cases of KSHV, the infection is a complex mixture of latent episomes and lytic productive infection. In this application, we investigate the mechanisms regulating gene expression from KSHV latent genomes, and how small molecule inhibitors may be developed to disrupt this process. Further elucidation of the molecular mechanisms regulating latency transcription will provide useful information for understanding and treating viral pathogenesis and disease.
Funding Period: 2005-07-01 - 2015-12-31
more information: NIH RePORT

Top Publications

  1. pmc Cohesins localize with CTCF at the KSHV latency control region and at cellular c-myc and H19/Igf2 insulators
    William Stedman
    Gene Regulation Program, The Wistar Institute, University of Pennsylvania, Philadelphia, PA 19104, USA
    EMBO J 27:654-66. 2008
  2. pmc Molecular basis for oligomeric-DNA binding and episome maintenance by KSHV LANA
    John F Domsic
    Gene Expression and Regulation Program, The Wistar Institute, Philadelphia, Pennsylvania, United States of America
    PLoS Pathog 9:e1003672. 2013
  3. pmc Epigenetic regulation of EBV and KSHV latency
    Horng Shen Chen
    The Wistar Institute, Philadelphia, PA 19104, United States
    Curr Opin Virol 3:251-9. 2013
  4. pmc Timeless-dependent DNA replication-coupled recombination promotes Kaposi's Sarcoma-associated herpesvirus episome maintenance and terminal repeat stability
    Jayaraju Dheekollu
    Wistar Institute, Philadelphia, Pennsylvania, USA
    J Virol 87:3699-709. 2013
  5. pmc Telomeres and viruses: common themes of genome maintenance
    Zhong Deng
    The Wistar Institute Philadelphia, PA, USA
    Front Oncol 2:201. 2012
  6. pmc Snapshots: chromatin control of viral infection
    David M Knipe
    Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA, USA
    Virology 435:141-56. 2013
  7. pmc CTCF regulates Kaposi's sarcoma-associated herpesvirus latency transcription by nucleosome displacement and RNA polymerase programming
    Hyojeung Kang
    College of Pharmacy, Kyungpook National University, Daegu, Republic of Korea
    J Virol 87:1789-99. 2013
  8. pmc Cohesins repress Kaposi's sarcoma-associated herpesvirus immediate early gene transcription during latency
    Horng Shen Chen
    The Wistar Institute, Philadelphia, Pennsylvania, USA
    J Virol 86:9454-64. 2012
  9. pmc Identification of host-chromosome binding sites and candidate gene targets for Kaposi's sarcoma-associated herpesvirus LANA
    Fang Lu
    The Wistar Institute, Philadelphia, Pennsylvania, USA
    J Virol 86:5752-62. 2012
  10. pmc Mechanism of glycyrrhizic acid inhibition of Kaposi's sarcoma-associated herpesvirus: disruption of CTCF-cohesin-mediated RNA polymerase II pausing and sister chromatid cohesion
    Hyojeung Kang
    The Wistar Institute, 3601 Spruce Street, Philadelphia, PA 19104 4268, USA
    J Virol 85:11159-69. 2011

Research Grants

  1. HORMONAL CONTROL OF CALCIUM METABOLISM
    John T Potts; Fiscal Year: 2013

Detail Information

Publications18

  1. pmc Cohesins localize with CTCF at the KSHV latency control region and at cellular c-myc and H19/Igf2 insulators
    William Stedman
    Gene Regulation Program, The Wistar Institute, University of Pennsylvania, Philadelphia, PA 19104, USA
    EMBO J 27:654-66. 2008
    ..We conclude that cohesin subunits associate with viral and cellular CTCF sites involved in complex gene regulation and chromatin organization...
  2. pmc Molecular basis for oligomeric-DNA binding and episome maintenance by KSHV LANA
    John F Domsic
    Gene Expression and Regulation Program, The Wistar Institute, Philadelphia, Pennsylvania, United States of America
    PLoS Pathog 9:e1003672. 2013
    ..The structural features of LANADBD suggest a novel mechanism of episome maintenance through DNA-binding induced oligomeric assembly. ..
  3. pmc Epigenetic regulation of EBV and KSHV latency
    Horng Shen Chen
    The Wistar Institute, Philadelphia, PA 19104, United States
    Curr Opin Virol 3:251-9. 2013
    ..In addition, gammaherpesviruses have acquired specialized tools to modulate the epigenetic processes that promote viral genome propagation and host-cell survival. ..
  4. pmc Timeless-dependent DNA replication-coupled recombination promotes Kaposi's Sarcoma-associated herpesvirus episome maintenance and terminal repeat stability
    Jayaraju Dheekollu
    Wistar Institute, Philadelphia, Pennsylvania, USA
    J Virol 87:3699-709. 2013
    ....
  5. pmc Telomeres and viruses: common themes of genome maintenance
    Zhong Deng
    The Wistar Institute Philadelphia, PA, USA
    Front Oncol 2:201. 2012
    ..Understanding the common strategies of viral and cellular genome maintenance may provide new insights into viral-host interactions and the mechanisms driving genetic instability in cancer...
  6. pmc Snapshots: chromatin control of viral infection
    David M Knipe
    Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA, USA
    Virology 435:141-56. 2013
    ....
  7. pmc CTCF regulates Kaposi's sarcoma-associated herpesvirus latency transcription by nucleosome displacement and RNA polymerase programming
    Hyojeung Kang
    College of Pharmacy, Kyungpook National University, Daegu, Republic of Korea
    J Virol 87:1789-99. 2013
    ..We propose that RNAPII interactions and nucleosome displacement serve as a biochemical basis for programming RNAPII in the KSHV transcriptional control region...
  8. pmc Cohesins repress Kaposi's sarcoma-associated herpesvirus immediate early gene transcription during latency
    Horng Shen Chen
    The Wistar Institute, Philadelphia, Pennsylvania, USA
    J Virol 86:9454-64. 2012
    ..Our findings implicate cohesins as a major repressor of KSHV lytic gene activation and show that they function coordinately with CTCF to regulate the switch between latent and lytic gene activity...
  9. pmc Identification of host-chromosome binding sites and candidate gene targets for Kaposi's sarcoma-associated herpesvirus LANA
    Fang Lu
    The Wistar Institute, Philadelphia, Pennsylvania, USA
    J Virol 86:5752-62. 2012
    ..Our data provide a potential mechanism through which LANA may regulate several host cell pathways by direct binding to gene regulatory elements...
  10. pmc Mechanism of glycyrrhizic acid inhibition of Kaposi's sarcoma-associated herpesvirus: disruption of CTCF-cohesin-mediated RNA polymerase II pausing and sister chromatid cohesion
    Hyojeung Kang
    The Wistar Institute, 3601 Spruce Street, Philadelphia, PA 19104 4268, USA
    J Virol 85:11159-69. 2011
    ....
  11. pmc Coordination of KSHV latent and lytic gene control by CTCF-cohesin mediated chromosome conformation
    Hyojeung Kang
    The Wistar Institute, Philadelphia, Pennsylvania, United States of America
    PLoS Pathog 7:e1002140. 2011
    ..Our findings indicate that KSHV genomes are organized into chromatin loops mediated by CTCF and cohesin interactions, and that these inter-chromosomal linkages coordinate latent and lytic gene control...
  12. pmc CTCF prevents the epigenetic drift of EBV latency promoter Qp
    Italo Tempera
    The Wistar Institute, Philadelphia, Pennsylvania, United States of America
    PLoS Pathog 6:e1001048. 2010
    ....
  13. pmc Regulation of Epstein-Barr virus OriP replication by poly(ADP-ribose) polymerase 1
    Italo Tempera
    The Wistar Institute, 3601 Spruce Street, Philadelphia, PA 19104, USA
    J Virol 84:4988-97. 2010
    ..We propose that PARP1-dependent PARylation of EBNA1 and adjacently bound TRF2 induces structural changes at the DS element that reduce EBNA1 DNA binding affinity and functional recruitment of ORC...
  14. pmc Epigenetic regulation of Kaposi's sarcoma-associated herpesvirus latency by virus-encoded microRNAs that target Rta and the cellular Rbl2-DNMT pathway
    Fang Lu
    The Wistar Institute, Philadelphia, Pennsylvania 19104, USA
    J Virol 84:2697-706. 2010
    ....
  15. pmc Chromatin organization of gammaherpesvirus latent genomes
    Italo Tempera
    The Wistar Institute, Philadelphia, PA 19104, USA
    Biochim Biophys Acta 1799:236-45. 2010
    ..We also discuss the roles of host cell factors, like CTCF and cohesins, that contribute to higher-order chromosome structures that may be important for stable gene expression programs during latent infection in proliferating cells...
  16. pmc Cell cycle control of Kaposi's sarcoma-associated herpesvirus latency transcription by CTCF-cohesin interactions
    Hyojeung Kang
    The Wistar Institute, Philadelphia, Pennsylvania 19104, USA
    J Virol 83:6199-210. 2009
    ....
  17. pmc CTCF binding to the first intron of the major immediate early (MIE) gene of human cytomegalovirus (HCMV) negatively regulates MIE gene expression and HCMV replication
    Francisco Puerta Martínez
    Department of Microbiology RCMI Program, Ponce School of Medicine and Health Sciences, Ponce, Puerto Rico, USA
    J Virol 88:7389-401. 2014
    ....

Research Grants30

  1. HORMONAL CONTROL OF CALCIUM METABOLISM
    John T Potts; Fiscal Year: 2013
    ....