Viral lncRNA: A regulatory molecule for controlling virus life cycle

Wang, Ziqiang; Zhao, Yiwan; Zhang, Yaou

A study on the regulatory roles of Kaposi's sarcoma-associated herpes-virus PAN RNA on viral and cellular gene expression showed that PAN RNA could maintain cellular transformation by affecting cellular gene expression, resulting in an enhanced growth phenotype, higher cell densities, and increased survival [7] . In Epstein-Barr virus (EBV)-associated carcinogenesis, EBV-miR-BART6-3p inhibited EBV-associated cancer cell migration and invasion by targeting and downregulating the lncRNA LOC553103 [39] . The Epstein-Barr early RNAs (EBERs) are two abundantly expressed and virally encoded lncRNAs in latently EBV-infected cells. A recent study of the in vivo effects of EBERs in cellular gene expression demonstrated that the EBERs regulated a variety of host cell genes, including deaminase, protein kinase, cell adhesion, regulation of apoptosis, and receptor signaling [40] . Moreover, EBER-1 enhanced host cell protein synthesis by blocking the activation of the double-stranded RNA-dependent eukaryotic initiation factor 2a (eIF-2a) protein kinase DAI (p68) [41] . EBERs have also been shown to impact the growth potential of Burkitt's lymphoma (BL) cells by mediating the stable relocalization of L22 from the nucleoli to the nucleoplasm [42] and inducing interleukin-10, which is a growth factor for virally infected cells [43] . These findings contribute to the potential ability of EBERs to establish or maintain a transformed phenotype in EBV-associated nasopharyngeal carcinoma [44] and in EBV-infected NIH 3T3 cells [45] . However, EBER-2 but not EBER-1 plays a critical role in viralinduced growth transformation in EBV-infected B cells [46] .