title: Kaposi's sarcoma herpesvirus microRNAs target caspase 3 and regulate apoptosis.
abstract: Kaposi's sarcoma herpesvirus (KSHV) encodes a cluster of twelve micro (mi)RNAs, which are abundantly expressed during both latent and lytic infection. Previous studies reported that KSHV is able to inhibit apoptosis during latent infection; we thus tested the involvement of viral miRNAs in this process. We found that both HEK293 epithelial cells and DG75 cells stably expressing KSHV miRNAs were protected from apoptosis. Potential cellular targets that were significantly down-regulated upon KSHV miRNAs expression were identified by microarray profiling. Among them, we validated by luciferase reporter assays, quantitative PCR and western blotting caspase 3 (Casp3), a critical factor for the control of apoptosis. Using site-directed mutagenesis, we found that three KSHV miRNAs, miR-K12-1, 3 and 4-3p, were responsible for the targeting of Casp3. Specific inhibition of these miRNAs in KSHV-infected cells resulted in increased expression levels of endogenous Casp3 and enhanced apoptosis. Altogether, our results suggest that KSHV miRNAs directly participate in the previously reported inhibition of apoptosis by the virus, and are thus likely to play a role in KSHV-induced oncogenesis.
authors.affiliation: Architecture et Réactivité de l'ARN, Institut de Biologie Moléculaire et Cellulaire du CNRS, Université de Strasbourg, Strasbourg, France.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Suffert
authors.forename: Georg
authors.initials: G
authors.lastname: Malterer
authors.forename: Jean
authors.initials: J
authors.lastname: Hausser
authors.forename: Johanna
authors.initials: J
authors.lastname: Viiliäinen
authors.forename: Aurélie
authors.initials: A
authors.lastname: Fender
authors.forename: Maud
authors.initials: M
authors.lastname: Contrant
authors.forename: Tomi
authors.initials: T
authors.lastname: Ivacevic
authors.forename: Vladimir
authors.initials: V
authors.lastname: Benes
authors.forename: Frédéric
authors.initials: F
authors.lastname: Gros
authors.forename: Olivier
authors.initials: O
authors.lastname: Voinnet
authors.forename: Mihaela
authors.initials: M
authors.lastname: Zavolan
authors.forename: Päivi M
authors.initials: PM
authors.lastname: Ojala
authors.forename: Juergen G
authors.initials: JG
authors.lastname: Haas
authors.forename: Sébastien
authors.initials: S
authors.lastname: Pfeffer
mesh_terms: D017209:Apoptosis / Q000235:genetics*; D015152:Blotting, Northern; D015153:Blotting, Western; D053148:Caspase 3 / Q000096:biosynthesis* / Q000235:genetics; D002460:Cell Line; D015536:Down-Regulation; D015967:Gene Expression Regulation, Viral / Q000235:genetics; D006566:Herpesviridae Infections / Q000235:genetics* / Q000378:metabolism; D019288:Herpesvirus 8, Human / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D020287:In Situ Nick-End Labeling; D035683:MicroRNAs / Q000235:genetics*; D016297:Mutagenesis, Site-Directed; D020411:Oligonucleotide Array Sequence Analysis; D060888:Real-Time Polymerase Chain Reaction
chemical_list: D035683:MicroRNAs; D053148:Caspase 3