The Preliminary Study on Hepatitis B Virus Quasispecies X Gene and its Mutants

The HBV genetic heterogeneity in the patients with chroni c HBV infection was reported in this article. A set of spectific primers was syn thesized according to HBV DNA sequence of Chinese strain, the whole X region was amplified by PCR method from the serum of 9 patients with chronic HBV infection , and then the PCR products were subcloned into pGEM Teasy vectors. Clones were randomly selected to be sequenced. Comparison of the cloned sequence was made to find the difference. After being compared, each sequence of selected clones is o f difference. The point mutation scattered through X region. Deletion mutations were detected in 19 clones of 37(51.4%), which caused different carboxyl endings of X protein. There is a hot region (after 123 aa code) where deletion mutation frequently happens. There were HBV quasispecies groups in sera from patients wi t h chronic HBV infection. There was a hot deletion region near the 3’ end of X ge ne, resulting in losing its transactivating activity