Graduate School of Pharmaceutical Sciences, Hokkaido University, Kita-ku, Sapporo 060-0812, Japan.
Biochem Biophys Res Commun. 2013 Sep 6;438(4):613-8. doi: 10.1016/j.bbrc.2013.08.007. Epub 2013 Aug 11.
Legumain (EC 3.4.22.34) is an asparaginyl endopeptidase. Strong legumain activity was observed in the mouse kidney, and legumain was found to be highly expressed in tumors. We previously reported that bovine kidney annexin A2 was co-purified with legumain and that legumain cleaved the N-terminal region of annexin A2 at an Asn residue in vitro and in vivo. In this study, we found a p53-binding site in intron 1 of the human legumain gene using computational analysis. To determine whether transcription of the legumain gene is regulated by p53, HCT116 cells were transfected with p53 siRNA and the effect of knockdown of p53 expression on legumain expression was examined. The results showed that expression levels of both legumain mRNA and protein were decreased in the siRNA-treated cells. Furthermore, enzyme activity of legumain was also increased by doxorubicin and its activity was reduced by knockdown of p53 in HCT116 cells. These results suggest that legumain expression and its enzyme activity are regulated by p53.
组织蛋白酶 L（EC 3.4.22.34）是一种天冬酰胺内肽酶。在小鼠肾脏中观察到强烈的组织蛋白酶 L 活性，并且发现组织蛋白酶 L 在肿瘤中高度表达。我们之前报道过牛肾 annexin A2 与组织蛋白酶 L 共同纯化，并且组织蛋白酶 L 在体外和体内在 annexin A2 的 N 末端区域切割天冬酰胺残基。在这项研究中，我们使用计算分析在人组织蛋白酶 L 基因的内含子 1 中发现了一个 p53 结合位点。为了确定组织蛋白酶 L 基因的转录是否受 p53 调节，用 p53 siRNA 转染 HCT116 细胞，并检查 p53 表达敲低对组织蛋白酶 L 表达的影响。结果表明，siRNA 处理的细胞中组织蛋白酶 L mRNA 和蛋白的表达水平均降低。此外，在 HCT116 细胞中，阿霉素也增加了组织蛋白酶 L 的酶活性，而 p53 的敲低降低了其活性。这些结果表明组织蛋白酶 L 的表达及其酶活性受 p53 调节。
