Similarity of the secondary structure with identical seven bases in the pregenomic/genomic regions required for the replication of hepatitis B virus and hepatitis C virus

We described the existence of the similarity of the secondary structure in hepatitis B virus (HBV) packaging signal epsilon and in hepatitis C virus (HCV) 3'X tail, both of which are considered to be important for the viral replication cycle. Seven nucleotide (tit) sequence (5'-GGUGGCU-3') existed both in HBV epsilon tit 3169-3175 and HCV 3'X tail nt 1'-7'. Furthermore, the 7-nt sequence paired with the 6-nt sequence (5-'AGCCUC-3') of HBV epsilon (nt 3149-3154) and (5'-AGCCCU-3') of HCV 3'X tail (nt 15'-20'), to form the very similar secondary structure with one impaired U. We consider the possibility that the common biological characters shared by these viruses are derived from the recognition of this conserved secondary structure by the viral or cellular proteins.