Epstein-Barr virus-encoded microRNA BART15-3p promotes cell apoptosis partially by targeting BRUCE.

Abstract

Epstein-Barr Virus (EBV) generates a variety of viral microRNAs (miRNAs) by processing the BHRF1 and BamHI A rightward (BART) transcripts. BART miRNAs are expressed in all cells latently infected with EBV, but the functions of most BART miRNAs remain unknown. The results of a cell proliferation assay revealed that miR-BART15-3p inhibited cell proliferation. Fluorescence-activated cell sorting following staining with annexin V or propidium iodide showed that miR-BART15-3p promoted apoptosis. Furthermore, the inhibitor for miR-BART15-3p increased cell growth and reduced apoptosis in EBV-infected cells. Using bioinformatic analyses, we predicted that miR-BART15-3p may target the antiapoptotic B-cell lymphoma 2 (BCL2), BCL2L2, DEAD (Asp-Glu-Ala-Asp) box polypeptide 42 (DDX42), and baculovirus inhibitor of apoptosis repeat-containing ubiquitin-conjugating enzyme (BRUCE) mRNAs. The luciferase reporter assay showed that only the 3' untranslated region (UTR) of BRUCE was affected by miR-BART15-3p. Two putative seed-matched sites for miR-BART15-3p were evident on the BRUCE 3' UTR. The results of a mutation study indicated that miR-BART15-3p hybridized only with the first seed-matched site on the BRUCE 3' UTR. miR-BART15-3p downregulated the BRUCE protein in EBV-negative cells, while the inhibitor for miR-BART15-3p upregulated the BRUCE protein in EBV-infected cells without affecting the BRUCE mRNA level. miR-BART15-3p was secreted from EBV-infected gastric carcinoma cells, and the level of miR-BART15-3p was 2- to 16-fold higher in exosomes than in the corresponding cells. Our data suggest that miR-BART15-3p can induce apoptosis partially by inhibiting the translation of the apoptosis inhibitor BRUCE. Further study is warranted to understand the role of miR-BART15-3p in the EBV life cycle.

• Authors: Hoyun Choi, Hanna Lee, Sae Rom Kim, Yong Song Gho, Suk Kyeong Lee
• Journal: Journal of virology (J Virol) Vol. 87 Issue 14 Pg. 8135-44 (Jul 2013) ISSN: 1098-5514 [Electronic] United States
• PMID: 23678170 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Annexin A5
• BIRC6 protein, human
• DNA Primers
• Inhibitor of Apoptosis Proteins
• MicroRNAs
• Propidium
• Luciferases

Topics

• Analysis of Variance
• Annexin A5
• Apoptosis (physiology)
• Blotting, Western
• Cell Line, Tumor
• Cell Proliferation (drug effects)
• Computational Biology
• DNA Primers (genetics)
• Flow Cytometry
• Herpesvirus 4, Human (genetics)
• Humans
• Inhibitor of Apoptosis Proteins (metabolism)
• Luciferases
• MicroRNAs (genetics, metabolism, pharmacology)
• Microscopy, Electron, Transmission
• Plasmids (genetics)
• Propidium
• RNA Interference
• Reverse Transcriptase Polymerase Chain Reaction