To provide a new RNA sequence at the 3'-terminal sequence of an HCV (hepatitis C virus) genome RNA.

A 3' sequence having a specific base sequence of the HCV (hepatitis virus) genome RNA, a complement thereof and use thereof for nucleic acid-based diagnosis and new anti-HCV therapies are provided. The sequence element which is conserved among the HCV genotypes is essential for viral replication and required for construction of full-length HCV cDNA clones yielding an infectious RNA, a progeny virus or replication-competent HCV replicons. The functional clones are useful tools for evaluation of the therapeutic approaches and as substances for developing candidate attenuated or inactivated HCV derivatives for vaccination against HCV.