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
Artemia embryos can endure extreme temperature, long-term anoxia, desiccation and other wide variety of stressful conditions. How the embryos survive these stresses is a very interesting and unsolved subject. To solve...Artemia embryos can endure extreme temperature, long-term anoxia, desiccation and other wide variety of stressful conditions. How the embryos survive these stresses is a very interesting and unsolved subject. To solve this question we analyzed the nucleotide and deduced protein sequence for Hsp26, a molecular chaperone specific to Artemia embryo development, cDNAs of Hsp26 were sequenced from eight Artemia species and deduced Hsp26 amino acid sequences were analyzed. Computer-assisted analysis indicated that the 5＇-untranslated region and all the 3 introns contain many putative cis-acting elements for Hsp26 gene expression during development, including heat shock elements （HSEs）, Dfd, dl, CF2-II, Hb and AP-1 binding sites. Secondary structure of the Hsp26 3＇-untranslated terminator contains the basic structure basis for transcriptional termination. Hsp26 shares sequence similarity with sHSPs （small heat shock protein） from other organisms. The physico-chemical properties of the deduced protein, such as theoretical molecular weight, protein extinction coefficient, isoelectric point and antigenic sites were also obtained. One seven-peptide nuclear localization signals （NLS） ＂PFRRRMM＂ was found, which suggested that the Hsp26 protein was hypothesized to be located inside the nucleus. The numbers of phosphorylation sites of serine, threonine and tyrosine and kinase specific phosphorylation sites are also located in Hsp26 protein sequence. These studies will help us achieve a better understanding of Hsp26 and broad implications for sHSPs function in crustacean embryo development.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Artemia embryos can endure extreme temperature, long-term anoxia, desiccation and other wide variety of stressful conditions. How the embryos survive these stresses is a very interesting and unsolved subject. To solve this question we analyzed the nucleotide and deduced protein sequence for Hsp26, a molecular chaperone specific to Artemia embryo development, cDNAs of Hsp26 were sequenced from eight Artemia species and deduced Hsp26 amino acid sequences were analyzed. Computer-assisted analysis indicated that the 5＇-untranslated region and all the 3 introns contain many putative cis-acting elements for Hsp26 gene expression during development, including heat shock elements （HSEs）, Dfd, dl, CF2-II, Hb and AP-1 binding sites. Secondary structure of the Hsp26 3＇-untranslated terminator contains the basic structure basis for transcriptional termination. Hsp26 shares sequence similarity with sHSPs （small heat shock protein） from other organisms. The physico-chemical properties of the deduced protein, such as theoretical molecular weight, protein extinction coefficient, isoelectric point and antigenic sites were also obtained. One seven-peptide nuclear localization signals （NLS） ＂PFRRRMM＂ was found, which suggested that the Hsp26 protein was hypothesized to be located inside the nucleus. The numbers of phosphorylation sites of serine, threonine and tyrosine and kinase specific phosphorylation sites are also located in Hsp26 protein sequence. These studies will help us achieve a better understanding of Hsp26 and broad implications for sHSPs function in crustacean embryo development.
