Pugh C W, Ebert B L, Ebrahim O, Ratcliffe P J
Institute of Molecular Medicine, John Radcliffe Hospital, Headington, Oxford, UK.
Biochim Biophys Acta. 1994 Apr 6;1217(3):297-306. doi: 10.1016/0167-4781(94)90289-5.
We have analysed sequences within the mouse erythropoietin enhancer which are required for oxygen regulated operation in the erythropoietin producing cell line, HepG2, and in two non-erythropoietin producing cell lines; the lung fibroblastoid cell line a23, and mouse erythroleukaemia (MEL) cells. At least three critical sites were demonstrated within a 96 nucleotide sequence. Oxygen regulated operation was dependent on sites within the first 26 nucleotides. Sequences lying 3' to this region modulated enhancer function but did not themselves convey oxygen regulated operation. In HepG2 cells these 3' sequences co-operated to permit operation of the inducible element at a distance from a promoter, but in MEL cells 3' sequences repressed activity of the inducible element. Though operation of this 3' sequence differed according to the cell type, oxygen regulated operation was dependent on the same two critical sites in the 5' region in both erythropoietin producing and non-erythropoietin producing cells. These findings support the existence of a widespread oxygen sensing system in mammalian cells which is similar to that operating in specific cells to regulate erythropoietin production, and they indicate that the system activates factors with similar DNA sequence specificity in different cells.
我们分析了小鼠促红细胞生成素增强子中的序列，这些序列对于促红细胞生成素产生细胞系HepG2以及两种非促红细胞生成素产生细胞系（肺成纤维样细胞系a23和小鼠红白血病（MEL）细胞）中的氧调节作用是必需的。在一个96个核苷酸的序列中至少证明了三个关键位点。氧调节作用取决于前26个核苷酸内的位点。位于该区域3'端的序列调节增强子功能，但它们本身并不传递氧调节作用。在HepG2细胞中，这些3'序列协同作用，使诱导元件在远离启动子的位置发挥作用，但在MEL细胞中，3'序列抑制诱导元件的活性。尽管该3'序列的作用因细胞类型而异，但在促红细胞生成素产生细胞和非促红细胞生成素产生细胞中，氧调节作用都依赖于5'区域中相同的两个关键位点。这些发现支持了哺乳动物细胞中存在一种广泛的氧感应系统，该系统类似于在特定细胞中调节促红细胞生成素产生的系统，并且表明该系统在不同细胞中激活具有相似DNA序列特异性的因子。
