Mutations of the X region of hepatitis B virus and their clinical implications
Version of Record online: 12 DEC 2008
© 1997 The Japanese Society of Pathology
Volume 47, Issue 4, pages 183–193, April 1997
How to Cite
Uchida, T., Saltoh, T. and Shinzawa, H. (1997), Mutations of the X region of hepatitis B virus and their clinical implications. Pathology International, 47: 183–193. doi: 10.1111/j.1440-1827.1997.tb04479.x
- Issue online: 12 DEC 2008
- Version of Record online: 12 DEC 2008
- Received 15 October 1996. Accepted for publication 5 November 1996.
- hepatitis B virus;
- X gene;
- X protein
Nucleotide (nt) sequences of the X region of more than 130 hepatitis B virus (HBV) Isolates were determined and derived from patients with a variety of clinical features. Correlation of not substitutions with clinicopathological characteristies was attempted. The X region (465nt) Is crucial for the replication and expression of HBV because the X protein trans-activates the HBV genes and this region contains the core promoter, enhancer II, and two direct repeats. There are several mutational hotspots, some of which seem to relate to immunological epitopes of the X protein. Two kinds of mutations which have important clinical significances were found. One is an 8-nt deletion between nt 1770 and 1777, which truncates 20 amino acids from the carboxyl terminus of the X protein. This deletion leads to the suppression of replication and expression of HBV DNA, resulting In immunoserological marker (HBsAg) negativity. This silent HBV infection Is responsible for the majority of non A to non-E hepatitis. The other mutation substituting T for C (nt 1655), T for A (nt 1764) and A for G (nt 1766) seems to relate to fulminant hepatitis. Further sequencing studies and In vitro mutagenesis experiments will clarify the significance of other mutations of the X region.