2 PURIFIED FACTORS BIND TO THE SAME SEQUENCE IN THE ENHANCER OF MOUSE MHC CLASS-I GENES - ONE OF THEM IS A POSITIVE REGULATOR INDUCED UPON DIFFERENTIATION OF TERATOCARCINOMA CELLS
2 PURIFIED FACTORS BIND TO THE SAME SEQUENCE IN THE ENHANCER OF MOUSE MHC CLASS-I GENES - ONE OF THEM IS A POSITIVE REGULATOR INDUCED UPON DIFFERENTIATION OF TERATOCARCINOMA CELLS
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DOI：
10.1093/nar/17.13.5245
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发表时间：
1989-07-11
影响因子：
14.9
通讯作者：
KOURILSKY, P
中科院分区：
文献类型：
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作者：
ISRAEL, A;YANO, O;KOURILSKY, P
MHC I类鼠基因和β-2-微球蛋白基因在胚胎癌（EC）细胞中是沉默的，但在这些细胞分化时被诱导。我们以前已经表明，位于H-2Kb基因的启动子中的增强子样序列在F9和PCC 3细胞中是无功能的。我们先前已经从小鼠T细胞系中纯化了一种48 kd的蛋白质（KBF 1），该蛋白质与位于该增强子中的回文序列和β-2-微球蛋白基因启动子中的类似序列结合。我们在此描述了也与该序列结合的第二种蛋白质（KBF 2，58 kd）的纯化。虽然这两种活性都存在于分化的细胞中，但KBF 1结合活性在未分化的EC细胞中不存在，其中回文序列不显示增强子活性。分化后，KBF 1结合活性被诱导，回文序列作为增强子变得有活性。因此，在未分化的EC细胞中KBF 1活性的缺乏至少部分地导致了这些细胞中H-2 I类和β-2-微球蛋白基因表达的缺乏，并表明KBF 1活性在分化过程中受到调节。
The MHC class I murine and beta-2-microglobulin genes are silent in embryonal carcinoma (EC) cells but are induced upon differentiation of these cells. We have previously shown that enhancer-like sequences located in the promoter of the H-2Kb gene are non-functional in F9 and PCC3 cells. We have previously purified a 48 kd protein (KBF1) from a mouse T cell line which binds to a palindromic sequence located in this enhancer and to a similar sequence in the promoter of the beta-2-microglobulin gene. We describe here the purification of a second protein (KBF2, 58 kd) which also binds to this sequence. While both activities are present in differentiated cells, KBF1 binding activity is absent in undifferentiated EC cells, where the palindromic sequence shows no enhancer activity. Upon differentiation, KBF1 binding activity is induced and the palindromic sequence becomes active as an enhancer. Thus, the absence of the KBF1 activity in undifferentiated EC cells is at least in part responsible for the lack of expression of H-2 class I and beta-2-microglobulin genes in these cells and suggests that KBF1 activity is regulated during differentiation.