Roles of LncRNAs in Viral Infections

Liu, Weiwei; Ding, Chan

In influenza virus infection, Ouyang et al found the expression of the lncRNA NRAV was down regulated after infection with a DNA virus (HSV) and with RNA viruses (SeV and MDRV) (Ouyang et al., 2014) . NRAV promotes influenza A virus (IAV) replication and virulence and negatively regulates the expression of several critical IFN-stimulated genes (ISGs), including IFIT2, IFIT3, IFITM3, OASL, and MxA. Among these ISGs, the level of MxA was most significantly affected by the expression of NRAV and negatively correlated with NRAV expression. NRAV inhibits the initial transcription of MxA and IFITM3 by regulating histone modifications H3K4me3 and H3K27me3 of the ISG genes. LncBST2/BISPR is expressed from the position in the genome divergent from the well characterized BST2 (a key host cell defense molecule), and lncBST2/BISPR is induced in cells infected with mutants of influenza or VSV. Furthermore, lncBST2/BISPR is upregulated in response to IFN stimulation and was identified as a positive regulator of BST expression. Meanwhile, lncBST2/BISPR is also induced in cells infected with hepatitis C virus (HCV) and in the liver of patients with HCV infections (Barriocanal et al., 2015) . Although, lncRNAs, NRAV, and lncBST2, were found in anti-viral response, the specific mechanisms of how they regulate ISG expression have not been elucidated.