Co-transcribed 3' host sequences augment expression of integrated hepatitis B virus DNA.
We have previously reported the cloning and structural analysis of integrated hepatitis B virus DNA copies from the human hepatoma cell line PLC/PRF/5. Here we show that the cloned DNA fragments of 10.7 kb and 10.5 kb contain intact coding sequences for HBsAg since Ltk- cells transfected with these DNAs secrete considerable amounts of HBsAg. We show for the 10.7-kb fragment that multiple readthrough messages composed of viral as well as cellular sequences are transcribed. These RNAs differ only in their 3' sequences. Furthermore, the 10.7-kb insert leads to a substantial increase in HBsAg produced compared with HBV DNA and with the 10.5-kb insert. We provide evidence that the different 3' sequences on the HBsAg transcripts account for the augmentation of expression.
von Loringhoven
A F
AF
Koch
S
S
Hofschneider
P H
PH
Koshy
R
R
D000818:Animals; D006528:Carcinoma, Hepatocellular / Q000209:etiology; D002874:Chromosome Mapping; D002999:Clone Cells / Q000276:immunology; D004279:DNA, Viral / Q000235:genetics*; D005786:Gene Expression Regulation; D005814:Genes, Viral; D006514:Hepatitis B Surface Antigens / Q000235:genetics; D006515:Hepatitis B virus / Q000235:genetics*; D008113:Liver Neoplasms; D051379:Mice; D012333:RNA, Messenger / Q000235:genetics; D012367:RNA, Viral / Q000235:genetics; D014158:Transcription, Genetic; D014162:Transfection
D004279:DNA, Viral; D006514:Hepatitis B Surface Antigens; D012333:RNA, Messenger; D012367:RNA, Viral