Kaposi's Sarcoma-Associated Herpesvirus-Encoded LANA Recruits Topoisomerase IIβ for Latent DNA Replication of the Terminal Repeats

Purushothaman, Pravinkumar; McDowell, Maria E.; McGuinness, James; Salas, Ruth; Rumjahn, Sharif M.; Verma, Subhash C.

doi:10.1128/jvi.00839-12

Cited by 25 publications

(31 citation statements)

References 71 publications

(137 reference statements)

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“…LANA interacts with and recruits ORCs to TR DNA, presumably to initiate a prereplicative complex (23,36,37). Notably, LANA also interacts with replication protein As (38) and topoisomerase IIβ (39), raising the possibility that these proteins may also function in downstream, rate-limiting steps. Additional, non-TR replication origins also occur in latent KSHV (34).…”

Section: Discussionmentioning

confidence: 99%

Kaposi's sarcoma-associated herpesvirus LANA recruits the DNA polymerase clamp loader to mediate efficient replication and virus persistence

Sun

Tsurimoto

Juillard

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

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Significance Kaposi's sarcoma herpesvirus (KSHV) latently infects tumor cells, and viral episomal DNA replicates once each cell cycle. KSHV does not express DNA replication proteins during latency. Instead, KSHV latency-associated nuclear antigen (LANA) recruits host cell DNA replication machinery to the replication origin. However, the mechanism by which LANA mediates replication is uncertain. Here, we show LANA recruits replication factor C, the DNA polymerase clamp [proliferating cell nuclear antigen (PCNA)] loader, in a critical step for viral DNA replication. Our findings suggest that PCNA loading is a rate-limiting step in DNA replication that is incompatible with KSHV persistence. LANA-enhanced PCNA loading is necessary for virus replication and persistent infection. These data reveal a therapeutic target for inhibition of KSHV persistence in malignant cells.

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Section: Discussionmentioning

confidence: 99%

Kaposi's sarcoma-associated herpesvirus LANA recruits the DNA polymerase clamp loader to mediate efficient replication and virus persistence

Sun

Tsurimoto

Juillard

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

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“…However, LANA has not been shown to interact physically with these proteins. Topoisomerase II␤ (TopoII␤) induces double-stranded DNA (dsDNA) breaks during DNA replication (46), and ellipticine, a TopoII␤ inhibitor, reduced KSHV TR DNA replication. TopoII␤ associates with LANA, but the association is with the N-terminal portion of LANA, which was present in all mutants.…”

Section: Discussionmentioning

confidence: 99%

Identification of Kaposi's Sarcoma-Associated Herpesvirus LANA Regions Important for Episome Segregation, Replication, and Persistence

Vázquez

Carey

Kaye

2013

J Virol

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Kaposi's sarcoma-associated herpesvirus (KSHV) latency-associated nuclear antigen (LANA) is a 1,162-amino-acid protein that mediates the maintenance of episomal viral genomes in latently infected cells. The two central components of episome persistence are DNA replication with each cell division and the segregation of DNA to progeny nuclei. LANA self-associates to bind KSHV terminal-repeat (TR) DNA and to mediate its replication. LANA also simultaneously binds to TR DNA and mitotic chromosomes to mediate the segregation of episomes to daughter nuclei. The N-terminal region of LANA binds histones H2A and H2B to attach to mitotic chromosomes, while the C-terminal region binds TR DNA and also associates with chromosomes. Both the N-and C-terminal regions of LANA are essential for episome persistence. We recently showed that deletion of all internal LANA sequences results in highly deficient episome maintenance. Here we assess independent internal LANA regions for effects on episome persistence. We generated a panel of LANA mutants that included deletions in the large internal repeat region and in the unique internal sequence. All mutants contained the essential N-and C-terminal regions, and as expected, all maintained the ability to associate with mitotic chromosomes in a wild-type fashion and to bind TR DNA, as assessed by electrophoretic mobility shift assays (EMSA). Deletion of the internal regions did not reduce the half-life of LANA. Notably, deletions within either the repeat elements or the unique sequence resulted in deficiencies in DNA replication. However, only the unique internal sequence exerted effects on the ability of LANA to retain green fluorescent protein (GFP) expression from TR-containing episomes deficient in DNA replication, consistent with a role in episome segregation; this region did not independently associate with mitotic chromosomes. All mutants were deficient in episome persistence, and the deficiencies ranged from minor to severe. Mutants deficient in DNA replication that contained deletions within the unique internal sequence had the most-severe deficits. These data suggest that internal LANA regions exert critical roles in LANA-mediated DNA replication, segregation, and episome persistence, likely through interactions with key host cell factors.

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“…For reporter assays, transfections were done by using Metafectene (Biontex Laboratories, GmbH) according to the manufacturer's protocol. B cells were transfected by electroporation as described previously (51). Coimmunoprecipitation assays and Western blot analysis.…”

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confidence: 99%

Kaposi's Sarcoma-Associated Herpesvirus Latency-Associated Nuclear Antigen Inhibits Major Histocompatibility Complex Class II Expression by Disrupting Enhanceosome Assembly through Binding with the Regulatory Factor X Complex

Thakker

Purushothaman

Gupta

et al. 2015

J Virol

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Major histocompatibility complex class II (MHC-II Kaposi's sarcoma-associated herpesvirus (KSHV) is an oncogenic gammaherpesvirus that causes several malignancies, such as Kaposi's sarcoma (KS), primary effusion lymphomas (PELs), and multicentric Castleman's disease (MCD), in immunocompromised individuals (1, 2). The life cycle of KSHV consists of a predominant latent phase marked by restricted gene expression and a transient lytic replication phase characterized by the production of functional virions. KSHV maintains a lifelong persistent infection in susceptible hosts after primary infection (3, 4). One of the main factors contributing to the successful lifelong persistence of KSHV is its astounding ability to hide from host immune surveillance. During the course of evolution, KSHV has evolved multiple mechanisms to evade and modulate nearly all aspects of both the innate and adaptive immunities of infected hosts (5-7).Latency-associated nuclear antigen (LANA or LANA-1) is the most abundantly expressed protein in all KSHV-infected cells (8-10). LANA is a large multifunctional protein that plays diverse Citation Thakker S, Purushothaman P, Gupta N, Challa S, Cai Q, Verma SC. 2015. Kaposi's sarcoma-associated herpesvirus latency-associated nuclear antigen inhibits major histocompatibility complex class II expression by disrupting enhanceosome assembly through binding with the regulatory factor X complex.

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Kaposi's Sarcoma-Associated Herpesvirus-Encoded LANA Recruits Topoisomerase IIβ for Latent DNA Replication of the Terminal Repeats

Cited by 25 publications

References 71 publications

Kaposi's sarcoma-associated herpesvirus LANA recruits the DNA polymerase clamp loader to mediate efficient replication and virus persistence

Kaposi's sarcoma-associated herpesvirus LANA recruits the DNA polymerase clamp loader to mediate efficient replication and virus persistence

Identification of Kaposi's Sarcoma-Associated Herpesvirus LANA Regions Important for Episome Segregation, Replication, and Persistence

Kaposi's Sarcoma-Associated Herpesvirus Latency-Associated Nuclear Antigen Inhibits Major Histocompatibility Complex Class II Expression by Disrupting Enhanceosome Assembly through Binding with the Regulatory Factor X Complex

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