Epstein-Barr virus noncoding small RNA (EBER1) induces cell proliferation by up-regulating cellular mitochondrial...

Epstein-Barr virus encoded RNAs (EBER1 and EBER2) are two non-polyadenylated, non-protein coding small RNAs expressed at high levels in all forms of EBV latent infections. Although not directly involved in cell transformation, a number of studies have reported that these RNAs may be involved in cell proliferation. However, which of the two EBERs play a major role in this process and the mechanisms involved remains unknown. The aim of this study was to investigate the role and mechanism of EBER1-induced cell proliferation. Using stably transfected EBER1 cell lines, and multiple methodologies, we show that EBER1 transfected epithelial, B and T cell lines proliferate at a higher rate, have higher metabolic activity and increased DNA synthesis. The mitochondrial number and activity was also observed to be higher in the EBER1 transfected cells. Moreover, cytochrome c activity and store operated calcium entry (SOCE) were potentiated in the EBER1 expressing cells. Finally, the genes associated with cell proliferation were also observed to be up-regulated in the EBER1 transfected cells. Taken together, our data has unravelled the role of mitochondria and cellular calcium pathway that appear to be involved in EBER1 induced cell proliferation of EBV infected cells.