國家衛生研究院 NHRI:Item 3990099045/6316
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    Please use this identifier to cite or link to this item: http://ir.nhri.org.tw/handle/3990099045/6316


    Title: Suppressive regulation of KSHV RTA with O-GlcNAcylation
    Authors: Ko, YC;Tsai, WH;Wang, PW;Wu, IL;Lin, SY;Chen, YL;Chen, JY;Lin, SF
    Contributors: National Institute of Cancer Research
    Abstract: ABSTRACT: BACKGROUND: The replication and transcription activator (RTA) of Kaposi's sarcoma-associated herpesvirus (KSHV) is a molecular switch that initiates a productive replication of latent KSHV genomes. KSHV RTA (K-RTA) is composed of 691 amino acids with high Ser and Thr content (17.7%), but to what extent these Ser and Thr are modified in vivo has not been explored. METHODS: By using tandem mass spectrometric analysis of affinity-purified FLAG tagged K-RTA, we sought to identify Ser and Thr residues that are post-translationally modified in K-RTA. RESULTS: We found that K-RTA is an O-GlcNAcylated protein and Thr-366/Thr-367 is the primary motif with O-GlcNAcylation in vivo. The biological significance of O-GlcNAc modified Thr-366 and Thr-367 was assessed by site-specific amino acid substitution. Replacement of Thr with Ala at amino acid 366 or 367 caused a modest enhancement of K-RTA transactivation activity in a luciferase reporter assay and a cell model for KSHV reactivation. By using co-immunoprecipitation coupled with western blot analysis, we showed that the capacity of K-RTA in associating with endogenous PARP1 was significantly reduced in the Thr-366/Thr-367 O-GlcNAc mutants. PARP1 is a documented negative regulator of K-RTA that can be ascribed by the attachment of large negatively charged polymer onto K-RTA via PARP1's poly (ADP-ribose) polymerase activity. In agreement, shRNA-mediated depletion of O-GlcNAc transferase (OGT) in KSHV infected cells augmented viral reactivation and virus production that was accompanied by diminished K-RTA and PARP1 complexes. CONCLUSIONS: KSHV latent-lytic switch K-RTA is modified by cellular O-GlcNAcylation, which imposes a negative effect on K-RTA transactivation activity. This inhibitory effect involves OGT and PARP1, two nutritional sensors recently emerging as chromatin modifiers. Thus, we speculate that the activity of K-RTA on its target genes is continuously checked and modulated by OGT and PARP1 in response to cellular metabolic state.
    Date: 2012-02
    Relation: Journal of Biomedical Science. 2012 Feb;19(1):Article number 12.
    Link to: http://dx.doi.org/10.1186/1423-0127-19-12
    JIF/Ranking 2023: http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=NHRI&SrcApp=NHRI_IR&KeyISSN=1021-7770&DestApp=IC2JCR
    Cited Times(WOS): https://www.webofscience.com/wos/woscc/full-record/WOS:000300887600001
    Cited Times(Scopus): http://www.scopus.com/inward/record.url?partnerID=HzOxMe3b&scp=84856481417
    Appears in Collections:[Su-Fang Lin] Periodical Articles
    [Jen-Yang Chen] Periodical Articles

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