POLYPEPTIDE DERIVED FROM VARIANT HEPATITIS B VIRUS, GENE ENCODING THE SAME, AND RELATED DNA

摘要

The invention provides a novel hepatitis virus that cannot be detected by any of the type A, B, C, D and E virus tests, determines the gene sequence thereof, and provides a means for developing an effective method of detection and diagnosis thereof. The sequencing of a polypeptide derived from the above-identified novel variant hepatitis B virus and a gene encoding the same is conducted by amplifying the nucleic acid obtained from the serum of a patient with hepatitis according to the polymerase chain reaction. Also found is a polypeptide encoded by the antisense sequence DNA of a gene derived from the X region of the HBV. The polypeptide has 161 amino acid residues. The X protein as a product of X genes of the HBV is known to be not only useful as an antigen for detecting HBV infection but also capable of activating transcription by the trans-action thereof on the enhancer of the HBV itself or the enhancer of the promoter sequence of another cell gene through the interaction with cell factors in normal liver cells. Therefore attention is paid to the participation of this protein in liver cancer. A polypeptide containing the whole or part of the amino acid sequence encoded by the antisense sequence DNA derived from the X region of the above novel HBV is thought to be useful in the development of a hepatitis virus detection system and the development of efficacious antiviral and antitumor drugs through the development of a transcription activity detection system.