Fujii M, Saijoh K, Kobayashi T, Fujii S, Lee M J, Sumino K
Department of Public Health, Kobe University School of Medicine, Japan.
Gene. 1997 Oct 15;199(1-2):211-7. doi: 10.1016/s0378-1119(97)00369-7.
Selenoprotein P-like protein, similar to selenoprotein P, uses multiple TGAs for incorporation of selenocysteines but not as stop codons. It is also characterized by having a His-Pro-rich domain and a regionally differential expression pattern. Hence, in addition to selenium metabolism, this protein is considered to have a developmental function. In the present study, the structure of the selenoprotein P-like protein gene was analyzed. The gene consisted of five exons, and the 5'-flanking region contained a TATA box, TCF-1-CS, bHLH-CS, gamma-IRE-CS, c-Myb-CS, C/EBP-CS, HNF-5-CS, MRE2-CS, etc. The presence of motifs like TCF-1-CS, c-Myb-CS, etc. supports the suggestion that this protein is involved in cellular maturation. Since the presence of MRE2-CS suggests that this protein is related to the antidote effect of selenium against heavy metal intoxication, the availability of this motif was examined using bovine kidney cell lines, CKT-1 and MDBK. Metallothionein mRNA markedly increased 6 h after administration of 10(-6) M CdCl2 and ZnCl2 in both cell lines. No significant alteration was observed in selenoprotein P-like protein mRNA, whereas its basal expression was high, indicating that this protein is constitutively expressed. Thus, it is still possible that this protein acts as an antidote, even though it is not inducible by heavy metals.
硒蛋白P样蛋白，与硒蛋白P相似，使用多个TGA来掺入硒代半胱氨酸而非作为终止密码子。它还具有富含组氨酸 - 脯氨酸的结构域和区域差异表达模式的特征。因此，除了硒代谢外，该蛋白还被认为具有发育功能。在本研究中，对硒蛋白P样蛋白基因的结构进行了分析。该基因由五个外显子组成，其5'侧翼区域包含一个TATA盒、TCF-1结合位点、bHLH结合位点、γ-铁反应元件结合位点、c-Myb结合位点、C/EBP结合位点、HNF-5结合位点、MRE2结合位点等。TCF-1结合位点、c-Myb结合位点等基序的存在支持了该蛋白参与细胞成熟的推测。由于MRE2结合位点的存在表明该蛋白与硒对重金属中毒的解毒作用有关，因此使用牛肾细胞系CKT-1和MDBK检测了该基序的可用性。在两种细胞系中，给予10(-6)M CdCl2和ZnCl2后6小时，金属硫蛋白mRNA显著增加。硒蛋白P样蛋白mRNA未观察到明显变化，但其基础表达较高，表明该蛋白是组成型表达的。因此，即使它不能被重金属诱导，该蛋白仍有可能起到解毒作用。
