Temporal aspects of major viral transcript expression in Hep G2 cells transfected with cloned hepatitis B virus DNA: with emphasis on the X transcript

Virology. 1991 Dec;185(2):644-51. doi: 10.1016/0042-6822(91)90535-j.


The major transcripts of hepatitis B virus (HBV) and the kinetics of their expression were studied in a transient expression system by transfecting partially duplicated copies of HBV genome into Hep G2 cells. By Northern blotting, six species of HBV-specific transcripts could be identified. They were the pregenomic (3.6 kb), the preS1 (2.6 kb), the preS2/S (2.2 kb), the X (0.8 kb), and two spliced (2.2 kb) RNAs, respectively. The preS2/S RNA and the spliced RNAs could be distinguished when a core gene-specific probe, which could not hybridize with the former, was used. Kinetic analysis of the expression of these RNAs revealed that the X transcript exhibited a pattern different from that of other viral transcripts. Amounts of all RNAs peaked at 24-48 hr post-transfection and then gradually declined. However, the X transcript became undetectable on Day 4 post-transfection while other viral RNAs persisted for at least 10 days. The unique expression profile of the X transcript suggested that it probably behaves as an early gene and this is consistent with its proposed role as a transactivator. Nevertheless, frameshift mutations within the X ORF had no obvious effects on the activities and temporal pattern of HBV transcription in this transient expression system.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Base Sequence
  • Blotting, Northern
  • Gene Expression / genetics*
  • Genes, Overlapping / genetics
  • Hepatitis B virus / genetics*
  • Humans
  • Kinetics
  • Molecular Sequence Data
  • Mutation / genetics
  • Open Reading Frames / genetics
  • Plasmids / genetics
  • RNA Splicing / genetics
  • RNA, Viral / genetics*
  • Trans-Activators / genetics*
  • Transcription, Genetic / genetics
  • Transfection
  • Tumor Cells, Cultured


  • RNA, Viral
  • Trans-Activators
  • hepatitis B virus X protein