Abstract
Kaposi’s sarcoma-associated herpesvirus (KSHV) microRNAs are encoded in the latency-associated region. Knockdown of KSHV miR-K12-3 and miR-K12-11 increased expression of lytic genes in BC-3 cells, and increased virus production from latently infected BCBL-1 cells. Furthermore, iSLK cells infected with miR-K12-3 and miR-K12-11 deletion mutant viruses displayed increased spontaneous reactivation and were more sensitive to inducers of reactivation than cells infected with wild type KSHV. Predicted binding sites for miR-K12-3 and miR-K12-11 were found in the 3’UTRs of the cellular transcription factors MYB, Ets-1, and C/EBPα, which activate RTA, the KSHV replication and transcription activator. Targeting of MYB by miR-K12-11 was confirmed by cloning the MYB 3’UTR downstream from the luciferase reporter. Knockdown of miR‑K12-11 resulted in increased levels of MYB transcript, and knockdown of miR-K12-3 increased both C/EBPα and Ets-1 transcripts. Thus, miR-K12-11 and miR-K12-3 contribute to maintenance of latency by decreasing RTA expression indirectly, presumably via down‑regulation of MYB, C/EBPα and Ets-1, and possibly other host transcription factors.
Highlights
Kaposi’s sarcoma-associated herpesvirus (KSHV), known as Human Herpesvirus 8 (HHV-8), is a DNA tumor virus that infects endothelial cells in vivo and is the etiological agent of Kaposi’s sarcoma (KS) [1]
To validate efficiency and specificity of 2'OMe antagomirs against KSHV miRNAs, knock-down was assessed by stem-loop TaqMan Quantitative PCR (qPCR) which measures the amount of mature miRNA
We note that miR-K12-3 and miR-K12-11 expression levels are higher in BC-3 cells compared to BCBL-1 cells used in previous screens [43,44]
Summary
Kaposi’s sarcoma-associated herpesvirus (KSHV), known as Human Herpesvirus 8 (HHV-8), is a DNA tumor virus that infects endothelial cells in vivo and is the etiological agent of Kaposi’s sarcoma (KS) [1]. KSHV has been linked to two B cell lymphoproliferative disorders, primary effusion lymphoma (PEL) and a subset of multicentric Castleman’s disease (MCD) [2,3]. During lytic replication and reactivation, genome-wide expression occurs in a temporally regulated cascade of immediate early, early, and late genes, which results in lysis of the host cell and release of progeny virus. During latency most tumor cells express only a limited number of genes, the majority residing in the latency-associated region, which encodes the latency-associated nuclear antigen (LANA), v-FLIP, v-cyclin, kaposin, and 12. A subset of cells express vIRF3, vIL-6, and K1 during latency [4,5,6,7,8,9,10,11,12]
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call