title: 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.affiliation: Research Institute of Immunobiology, Department of Medical Lifescience, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea.
authors.forename: Hoyun
authors.initials: H
authors.lastname: Choi
authors.forename: Hanna
authors.initials: H
authors.lastname: Lee
authors.forename: Sae Rom
authors.initials: SR
authors.lastname: Kim
authors.forename: Yong Song
authors.initials: YS
authors.lastname: Gho
authors.forename: Suk Kyeong
authors.initials: SK
authors.lastname: Lee
mesh_terms: D000704:Analysis of Variance; D017304:Annexin A5; D017209:Apoptosis / Q000502:physiology*; D015153:Blotting, Western; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D019295:Computational Biology; D017931:DNA Primers / Q000235:genetics; D005434:Flow Cytometry; D004854:Herpesvirus 4, Human / Q000235:genetics*; D006801:Humans; D051034:Inhibitor of Apoptosis Proteins / Q000378:metabolism*; D008156:Luciferases; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D046529:Microscopy, Electron, Transmission; D010957:Plasmids / Q000235:genetics; D011419:Propidium; D034622:RNA Interference; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D017304:Annexin A5; C401541:BIRC6 protein, human; D017931:DNA Primers; D051034:Inhibitor of Apoptosis Proteins; D035683:MicroRNAs; D011419:Propidium; D008156:Luciferases