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BioAssay: AID 2659

Summary of Broad Institute MLPCN Kaposi's Sarcoma Herpes Virus Latent Infection Project

Kaposi's sarcoma-associated herpes virus (KSHV) latently infects tumor cells and has an etiologic role in Kaposi's sarcoma and primary effusion lymphoma. In latent infection, the viral genome is not integrated into chromosomes and exists as ..more
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AID: 2659
Data Source: Broad Institute (2053-01_INHIBITORS_PROJECT)
BioAssay Type: Summary, Candidate Probes/Leads with Supporting Evidence
Depositor Category: NIH Molecular Libraries Probe Production Network
BioAssay Version:
Deposit Date: 2010-03-24
Modify Date: 2010-10-15
Target
Depositor Specified Assays
AIDNameTypeComment
2629Fluorescence Polarization Cell-Free Homogeneous Primary HTS to Identify Inhibitors of the LANA Histone H2A/H2B InteractionscreeningPrimary HTS
435023Fluorescence Polarization Cell-Free Homogeneous Dose Retest to Confirm Inhibitors of the LANA Histone H2A/H2B InteractionconfirmatoryConfirmatory Dose Retest
463198Fluorescence Polarization Cell-Free Homogeneous Counter Screen to Identify Inhibitors of DNA IntercalationotherSecondary Screen to identify DNA intercalators
463211Luminescent Cell-Based Counter Screen to Identify Non-Cytotoxic CompoundsconfirmatorySecondary Screen to identify non-cytotoxic compounds
588510Fluorescence Polarization Biochemical Secondary LANA-Nucleosome Assay_2053_04_Inhibitor_Dose_DryPowder_Activityconfirmatory
Description:
Primary Collaborators:
Kenneth Kaye,Brigham & Womens,Boston MA,kkaye@rics.bwh.harvard.edu,617-525-4256
Chantal Beauchemin,Brigham & Womens,Boston MA,cbeauchemin@rics.bwh.harvard.edu,617-525-4256

Project Overview:
Kaposi's sarcoma-associated herpes virus (KSHV) latently infects tumor cells and has an etiologic role in Kaposi's sarcoma and primary effusion lymphoma. In latent infection, the viral genome is not integrated into chromosomes and exists as
an episome (plasmid). Virus survival in rapidly dividing cells depends on a carefully orchestrated chain of events. Episomes must replicate in concert with cellular genetic material, and then efficiently segregate to progeny nuclei. KSHV achieves this through its latency associated nuclear antigen (LANA), which tethers viral DNA to mitotic chromosomes to efficiently partition episomes. LANA's N-terminal region is essential for efficient KSHV DNA replication and tethering to mitotic chromosomes. The N-terminal portion of LANA binds histones H2A and H2B to attach to host chromosomes. Crystal structure of N-terminal LANA complexed with the nucleosome reveals that LANA peptide forms a hairpin that interacts exclusively with an acidic region of H2A/H2B on the nucleosome surface that is implicated in the formation of higher order chromatin structure. Currently, there are no small molecule inhibitors available that affect any aspect of LANA function.

Since LANA is necessary for KSHV latent infection, chemical probes which block the essential LANA binding to the nucleosome would serve as extremely useful reagents to investigate LANA and KSHV biology. Such inhibitory small molecules would be of potential therapeutic benefit since tumor cell persistence is dependent on KSHV infection. Small molecules which bind to the acidic region on the nucleosomal surface to block LANA binding will also greatly facilitate investigation of this region of chromatin, which is rapidly emerging as a critical functional region of the nucleosome.

Project Goal:
Screen for and identify inhibitors of the LANA histone H2A/H2B interaction. The primary screen is an in vitro biochemical assay where compounds are screened using fluorescence polarization for interaction of FITC labeled LANA peptide with nucleosomes as a source of H2A/H2B histone dimers. The peptide contains the first 23 amino acids from the amino terminal portion of LANA. This sequence is essential for LANA's interaction with H2A/H2B
Keywords: Kaposi's Sarcoma, herpesvirus, KSHV, latency, LANA, histone
Additional Information
Grant Number: 1 R21 NS061738-01

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