UBIQUITOUS PRESENCE OF CELLULAR PROTEINS THAT SPECIFICALLY BIND TO THE 3'-TERMINAL REGION OF HEPATITIS-C VIRUS

The 3' terminal region (3'-X tail) of hepatitis C virus (HCV) genomic RNA forms a stable stem-loop structure. The 3'-X tail consists of 98 n ucleotides (nt) that are highly conserved among the HCV strains and su pposed to function as a cis-acting region for replication of negative strand RNA and/or viral encapsidation, In the present study, by UV cro ss-linking assay we found two kinds of cellular proteins of approximat ely 87 and 130 kDa, which specifically bind to the full-length 3'-X ta il (nt 1 to 98), but not the 3'- or 5'-truncated 3'-X tail, consisting of nt 1 to 50 or nt 51 to 98, respectively, These proteins were detec ted in human cell lines such as hepatic tumor cell lines and a T-lymph ocyte cell line and also in a human embryonic lung fibroblast cell str ain, In addition, human hepatocellular carcinoma tissues expressed the se proteins regardless of infection or uninfection of HCV. Furthermore , these proteins were also detected in normal human tissues derived fr om the lung, heart, kidney, stomach, intestine, and colon. Thus, these cellular proteins, which are ubiquitously present in human tissues, m ight be involved in viral replication and/or encapsidation. (C) 1998 A cademic Press.