论文部分内容阅读
The nucleotide sequences of cloned adw hepatitis B core antigens (HBcAg) which have differentlevels of expression have been determined by dideoxy chain-terminating method. The results indicatethat the different levels of gene expression is primarily due to the different structures of upstream se-quences before the initiator of HBcAg genes. The hepatitis B core gene in the low-expressed cloneforms a secondary structure before the initiator. This secondary structure has been removed by Bal-31exonuclease in the high-expressed clone and half of the structure removed in the mid-expressed clone.It is apparent that the transcription/translation of the hepatitis B core gene is somehow blocked be-cause of the secondary structure. Therefore, the amount of HBcAg synthesized in E. coli is dramati-cally reduced.
The different genes of cloned adw hepatitis B core antigens (HBcAg) which have different levels of expression have been determined by dideoxy chain-terminating method. The results indicate that the different levels of gene expression is due to the different structures of upstream se-quences before the initiator of HBcAg genes. The hepatitis B core gene in the low-expressed cloneforms a secondary structure before the initiator. This secondary structure has been removed by Bal-31 exonuclease in the high-expressed clone and half of the structure removed in the mid- expressed clone. It is apparent that the transcription / translation of the hepatitis B core gene is somehow blocked blocked-cause of the secondary structure. Therefore, the amount of HBcAg synthesized in E. coli is dramati-cally reduced.