Transthyretin(TTR) gene was highly expressed in normal liver and it has been found to be deleted in part of DNA samples from human hepatic cancer. Its mRNA expression was suppressed in most hepatoma samples. In order ...Transthyretin(TTR) gene was highly expressed in normal liver and it has been found to be deleted in part of DNA samples from human hepatic cancer. Its mRNA expression was suppressed in most hepatoma samples. In order to study the biological effect of TTR gene on the growth of hepatoma cells, a recombinant vector containing TTR cDNA was constructed by pCMV, then it was transfected into hepatoma cell lines SMMC-7721 and Q3.It has been demonstrated that the inhibition of growth rate of TTR cDNA transfected hepatoma cells was about 50%in strength compared with that of the control. This inhibition was further enhanced when the transfected hepatoma cells were treated with all-trans retinoic acid. Hepatoma cells of cell lines PLC/PRF/5, SMMC-7721 and Q3 as well as hepatoma cells SMMC-7721 transfected with pCMV or pCMV-TTR were analyzed for TTR expression by Northern hybridization. The low level of TTR expression was found in both hepatoma cell lines and in SMMC-7721cells transfected with pCMV alone. However, a remarkable TTR mRNA expression was observed in hepatoma SMMC-7721 cells transfected with pCMV-TTR. It seems possible that TTR gene might be a candidate of cancer suppressor gene for human hepatic cancer.展开更多
Cytosine deaminase gene of Escherichia coli strain H30 was cloned, and its initiation codon of ’GTG’ was mutated to ’ATG’ by PCR. Prokaryotic recombinant expression vector pBV220CD was constructed. Clone with high...Cytosine deaminase gene of Escherichia coli strain H30 was cloned, and its initiation codon of ’GTG’ was mutated to ’ATG’ by PCR. Prokaryotic recombinant expression vector pBV220CD was constructed. Clone with high enzyme activity were selected by detecting their specific activity of cytosine deaminase. 5FC（5FC, 5fluorocytosine） could induce the lethal toxicity to cells containing active CD gene. DNA sequence analysis indicated that there were 16 altered bases and 5 of them resulted in the alteration of amino acids in predicted peptide by comparing DNA sequence of the clone H30CD11 with high enzyme activity with CD gene reported in Gene Bank.展开更多
文摘Transthyretin(TTR) gene was highly expressed in normal liver and it has been found to be deleted in part of DNA samples from human hepatic cancer. Its mRNA expression was suppressed in most hepatoma samples. In order to study the biological effect of TTR gene on the growth of hepatoma cells, a recombinant vector containing TTR cDNA was constructed by pCMV, then it was transfected into hepatoma cell lines SMMC-7721 and Q3.It has been demonstrated that the inhibition of growth rate of TTR cDNA transfected hepatoma cells was about 50%in strength compared with that of the control. This inhibition was further enhanced when the transfected hepatoma cells were treated with all-trans retinoic acid. Hepatoma cells of cell lines PLC/PRF/5, SMMC-7721 and Q3 as well as hepatoma cells SMMC-7721 transfected with pCMV or pCMV-TTR were analyzed for TTR expression by Northern hybridization. The low level of TTR expression was found in both hepatoma cell lines and in SMMC-7721cells transfected with pCMV alone. However, a remarkable TTR mRNA expression was observed in hepatoma SMMC-7721 cells transfected with pCMV-TTR. It seems possible that TTR gene might be a candidate of cancer suppressor gene for human hepatic cancer.
文摘Cytosine deaminase gene of Escherichia coli strain H30 was cloned, and its initiation codon of ’GTG’ was mutated to ’ATG’ by PCR. Prokaryotic recombinant expression vector pBV220CD was constructed. Clone with high enzyme activity were selected by detecting their specific activity of cytosine deaminase. 5FC（5FC, 5fluorocytosine） could induce the lethal toxicity to cells containing active CD gene. DNA sequence analysis indicated that there were 16 altered bases and 5 of them resulted in the alteration of amino acids in predicted peptide by comparing DNA sequence of the clone H30CD11 with high enzyme activity with CD gene reported in Gene Bank.
