Nomoto K, Shibata N, Imai Y, Kitamura K, Nakamura K, Mizuno Y, Kikuchi K
Section of Biochemistry, Institute of Immunological Science, Hokkaido University, Kita-ku, Sapporo 060-0815, Japan.
Int J Oncol. 1998 Aug;13(2):331-4.
We have already reported the nucleotide sequence of 5'-flanking region of rat PP1alpha gene and identified the promoter region in NIH3T3 cells. Here we determined the promoter activity of PP1alpha gene in ascites hepatoma cells and compared with that of hepatocytes. Reporter analysis showed that the promoter activity was enhanced in an ascites hepatoma AH13 compared with normal hepatocytes at two regions, -37 to -198 bp and -492 to -848 bp upstream of the translation start site. At -37 to -198 bp region with high GC content, binding of Sp1 was markedly increased in all of five ascites hepatomas examined. At -492 to -848 bp region, two bands were clearly detected in two of the five ascites hepatomas, AH13 and AH7974F, by gel shift analysis. These results strongly suggest that the increase in PP1alpha mRNA expression in ascites hepatomas is at least in part due to the enhanced promoter activity of PP1alpha gene.
我们已经报道了大鼠PP1α基因5′侧翼区的核苷酸序列，并在NIH3T3细胞中鉴定出了启动子区域。在此，我们测定了PP1α基因在腹水肝癌细胞中的启动子活性，并与肝细胞的启动子活性进行了比较。报告基因分析表明，在翻译起始位点上游-37至-198 bp和-492至-848 bp这两个区域，与正常肝细胞相比，腹水肝癌AH13细胞中的启动子活性增强。在GC含量高的-37至-198 bp区域，在所检测的所有五种腹水肝癌中，Sp1的结合显著增加。在-492至-848 bp区域，通过凝胶迁移分析在五种腹水肝癌中的两种，即AH13和AH7974F中清晰检测到两条带。这些结果有力地表明，腹水肝癌中PP1α mRNA表达的增加至少部分归因于PP1α基因启动子活性的增强。
