title: MicroRNAs encoded by Kaposi's sarcoma-associated herpesvirus regulate viral life cycle.
abstract: Kaposi's sarcoma-associated herpesvirus (KSHV) is linked with Kaposi's sarcoma and lymphomas. The pathogenesis of KSHV depends on the balance between two phases of the viral cycle: latency and lytic replication. In this study, we report that KSHV-encoded microRNAs (miRNAs) function as regulators by maintaining viral latency and inhibiting viral lytic replication. MiRNAs are short, noncoding, small RNAs that post-transcriptionally regulate the expression of messenger RNAs. Of the 12 viral miRNAs expressed in latent KSHV-infected cells, we observed that expression of miR-K3 can suppress both viral lytic replication and gene expression. Further experiments indicate that miR-K3 can regulate viral latency by targeting nuclear factor I/B. Nuclear factor I/B can activate the promoter of the viral immediate-early transactivator replication and transcription activator (RTA), and depletion of nuclear factor I/B by short hairpin RNAs had similar effects on the viral life cycle to those of miR-K3. Our results suggest a role for KSHV miRNAs in regulating the viral life cycle.
authors.affiliation: Program for RNA Biology, Sanford-Burnham Medical Research Institute, 10901 North Torrey Pines Road, La Jolla, California 92037, USA.
authors.forename: Chih-Chung
authors.initials: CC
authors.lastname: Lu
authors.forename: Zhonghan
authors.initials: Z
authors.lastname: Li
authors.forename: Chia-Ying
authors.initials: CY
authors.lastname: Chu
authors.forename: Jiaying
authors.initials: J
authors.lastname: Feng
authors.forename: Jun
authors.initials: J
authors.lastname: Feng
authors.forename: Ren
authors.initials: R
authors.lastname: Sun
authors.forename: Tariq M
authors.initials: TM
authors.lastname: Rana
mesh_terms: D002460:Cell Line; D004261:DNA Replication; D004279:DNA, Viral / Q000096:biosynthesis; D015967:Gene Expression Regulation, Viral; D019288:Herpesvirus 8, Human / Q000235:genetics* / Q000502:physiology; D006801:Humans; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000378:metabolism*; D012514:Sarcoma, Kaposi / Q000503:physiopathology; D015534:Trans-Activators / Q000378:metabolism; D017735:Virus Latency; D014779:Virus Replication
chemical_list: D004279:DNA, Viral; D035683:MicroRNAs; D012333:RNA, Messenger; D015534:Trans-Activators