Article

Characterization of the Minimal Replicator of Kaposi's Sarcoma-Associated Herpesvirus Latent Origin

Division of Hematology/Oncology and Department of Molecular Genetics and Microbiology, Case Western Reserve University, Cleveland, OH, USA.
Journal of Virology (Impact Factor: 4.44). 03/2005; 79(4):2637-42. DOI: 10.1128/JVI.79.4.2637-2642.2005
Source: PubMed

ABSTRACT

The latency-associated nuclear antigen (LANA) of Kaposi's sarcoma-associated herpesvirus (KSHV) binds to two sites within
the 801-bp-long terminal repeat (TR) and is the only viral protein required for episomal maintenance. While two or more copies
of TR are required for long-term maintenance, a single TR confers LANA-dependent origin activity on plasmid DNA. Deletion
mapping revealed a 71-bp-long minimal replicator containing two distinctive sequence elements: LANA binding sites (LBS1/2)
and an adjacent 29- to 32-bp-long GC-rich sequence which we termed the replication element. Furthermore, the transcription
factor Sp1 can bind to TR outside the minimal replicator and contributes to TR's previously reported enhancer activity.

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Available from: Rolf Renne, Mar 04, 2014
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    • "KSHV encoded LANA is indispensable during latency and plays a crucial role in KSHV latent DNA replication. LANA binds directly to LBS-1/2 and the ori-P, with varying degrees of affinity (Garber et al., 2001; Grundhoff and Ganem, 2003; Hu and Renne, 2005). In cell culture system, it has been shown that expression of KSHV LANA alone is capable of maintaining and replicating KSHV TR containing episomes and synthetic plasmids (Ballestas and Kaye, 2001; Hu et al., 2002; Grundhoff and Ganem, 2003). "
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    ABSTRACT: Kaposi’ssarcomaassociatedherpesvirus(KSHV)orhumanherpesvirus8(HHV8)isamajoretiologicalagentformultipleseveremalignanciesinimmune-compromisedpatients.KSHVestablisheslifetimepersistenceintheinfectedindividualsanddisplaystwodistinctlifecycles,generallyaprolongedpassivelatent,andashortproductiveorlyticcycle.Duringlatentphase,theviralepisomeistetheredtothehostchromosomeandreplicatesonceduringeverycelldivision.Latency-associatednuclearantigen(LANA)isapredominantmultifunctionalnuclearproteinexpressedduringlatency,whichplaysacentralroleinepisometethering,replicationandperpetualsegregationoftheepisomesduringcelldivision.LANAbindscooperativelytoLANAbindingsites(LBS)withintheterminalrepeat(TR)regionoftheviralepisomeaswellastothecellularnucleosomalproteinstotetherviralepisometothehostchromosome.LANAhasbeenshowntomodulatemultiplecellularsignalingpathwaysandrecruitsvariouscellularproteinssuchaschromatinmodifyingenzymes,replicationfactors,transcriptionfactors,andcellularmitoticframeworktomaintainasuccessfullatentinfection.Although,manyotherregionswithintheKSHVgenomecaninitiatereplication,KSHVTRisimportantforlatentDNAreplicationandpossiblesegregationofthereplicatedepisomes.BindingofLANAtoLBSfavorstherecruitmentofvariousreplicationfactorstoinitiateLANAdependentDNAreplication.Inthisreview,wediscussthemolecularmechanismsrelevanttoKSHVgenomereplication,segregation,andmaintenanceoflatency.
    Full-text · Article · Feb 2016 · Frontiers in Microbiology
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    • "KSHV encoded LANA is indispensable during latency and plays a crucial role in KSHV latent DNA replication. LANA binds directly to LBS-1/2 and the ori-P, with varying degrees of affinity (Garber et al., 2001;Grundhoff and Ganem, 2003;Hu and Renne, 2005). In cell culture system, it has been shown that expression of KSHV LANA alone is capable of maintaining and replicating KSHV TR containing episomes and synthetic plasmids (Ballestas and Kaye, 2001;Hu et al., 2002;Grundhoff and Ganem, 2003). "
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    ABSTRACT: Kaposi’s sarcoma associated herpesvirus (KSHV) or human herpesvirus 8 (HHV8) is a major etiological agent for multiple severe malignancies in immunocompromised patients. KSHV establishes lifetime persistence in the infected individuals and displays two distinct life cycles, generally a prolonged passive latent, and a short productive or lytic cycle. During latent phase, the viral episome is tethered to the host chromosome and replicates once during every cell division. Latency-associated nuclear antigen (LANA) is a predominant multifunctional nuclear protein expressed during latency, which plays a central role in episome tethering, replication and perpetual segregation of the episomes during cell division. LANA binds cooperatively to LANA binding sites (LBS) within the terminal repeat (TR) region of the viral episome as well as to the cellular nucleosomal proteins to tether viral episome to the host chromosome. LANA has been shown to modulate multiple cellular signaling pathways and recruits various cellular proteins such as chromatin modifying enzymes, replication factors, transcription factors and cellular mitotic framework to maintain a successful latent infection. Although many other regions within the KSHV genome can initiate replication, KSHV TR is important for latent DNA replication and possible segregation of the replicated episomes. Binding of LANA to LBS favors the recruitment of various replication factors to initiate LANA dependent DNA replication. In this review, we discuss the molecular mechanisms relevant to KSHV genome replication, segregation, and maintenance of latency.
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    • "LANA has two binding sites called LANA binding sequences (LBS) in TR and replication origin of the KSHV genome in latency (ori-P) consists of the LBS and the following 32bp GCrich segment (32GC) (Garber, Hu, and Renne, 2002; Garber et al., 2001). One of two LBS is required for the viral replication at least but it is not enough, i.e., 32GC is also required (Hu and Renne, 2005). Though it remains to be solved how the viral ori-P is determined among repeated TR sequences and how 32GC is functioning, LANA has been reported to interact with components of cellular replication machinery; origin recognition complex 1 to 6 (ORC1~ORC6) (Verma et al., 2006). "

    Full-text · Chapter · Mar 2012
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