Structural analysis of small deletion mutants of hepatitis B virus / 中华传染病杂志

ABSTRACT

Objective To elucidate the genome organization of small deletion mutants of hepatitis B virus(HBV).Methods Amplified the HBV genomes by polymerase chain reaction from the serum of the patients with chronic hepatitis B and cloned the small HBV DNA less than 1 kb,then sequenced and analyzed the gene organization of these small deletion mutants of HBV.Results Totally one hundred and twenty-four small deletion mutants of HBV genomes categorized to sixty-four types were obtained and classified into three groups according to the criteria of the characteristics of gene organization,for example,spliced variants,regular deletion mutants and the deletion mutants with an internal poly (dA).All of these isolated mutants shared some common features as the deletion in coding regions and regulatory elements,66% of the mutants retained the cis elements crucial for the viral replication and encapsidation,while 48% retained the X region.Conclusions Small deletion mutants of HBV are commonly detected in the serum from chronic hepatitis B patients,the characteristic structure of such mutants implies that they might be closely co-related with the pathogenicity of HBV.The exact mechanisms need further study yet.