Epstein–Barr virus nuclear antigen 1 is a DNA-binding protein with strong RNA-binding activity Lu, Chih-Chung and Wu, Chia-Wei and Chang, Shin C. and Chen, Tzu-Yi and Hu, Chwan-Ren and Yeh, Ming-Yi and Chen, Jen-Yang and Chen, Mei-Ru,, 85, 2755-2765 (2004), doi = https://doi.org/10.1099/vir.0.80239-0, publicationName = Microbiology Society, issn = 0022-1317, abstract= Epstein–Barr virus (EBV) nuclear antigen 1 (EBNA-1) plays key roles in both the regulation of gene expression and the replication of the EBV genome in latently infected cells. To characterize the RNA-binding activity of EBNA-1, it was demonstrated that EBNA-1 binds efficiently to RNA homopolymers that are composed of poly(G) and weakly to those composed of poly(U). All three RGG boxes of EBNA-1 contributed additively to poly(G)-binding activity and could mediate RNA binding when attached to a heterologous protein in an RNA gel mobility-shift assay. In vitro-transcribed EBV and non-EBV RNA probes revealed that EBNA-1 bound to most RNAs examined and the affinity increased as the content of G and U increased, as demonstrated in competition assays. Among these probes, the 5′ non-coding region (NCR) (nt 131–278) of hepatitis C virus RNA appeared to be the strongest competitor for EBNA-1 binding to the EBV-encoded small nuclear RNA 1 (EBER1) probe, whereas a mutant 5′ NCR RNA with partially disrupted secondary structure was a weak competitor. Furthermore, the interaction of endogenous EBNA-1 and EBER1 in EBV-infected cells was demonstrated by a ribonucleoprotein immunoprecipitation assay. These results revealed that EBNA-1 is a DNA-binding protein with strong binding activity to a relatively broad spectrum of RNA and suggested an additional biological impact of EBNA-1 through its ability to bind to RNA., language=, type=