Nuclear factor 1 family proteins bind to the silencer element in the rat glutathione transferase P gene.
Nuclear factor 1 family proteins bind to the silencer element in the rat glutathione transferase P gene.
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核因子 1 家族蛋白与大鼠谷胱甘肽转移酶 P 基因中的沉默元件结合。
DOI：
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发表时间：
1997
期刊：
影响因子：
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通讯作者：
M. Imagawa
中科院分区：
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作者：
S. Osada;S. Daimon;T. Ikeda;T. Nishihara;K. Yano;M. Yamasaki;M. Imagawa
我们已经在谷胱甘肽转移酶P(GST-P)基因中发现了一个沉默区域，其在大鼠肝脏中的表达完全被抑制。至少有三个反式作用因子与该区域的多个顺式元件结合。由于GST-P沉默因子4(GSP4)是该沉默因子中的主要成分，我们纯化了GSP4结合蛋白，称为沉默因子A(SF-A)。将纯化的SF-A在SDS-聚丙烯酰胺凝胶上分离成多个蛋白质，并测定了SF-A的四个主要组分的氨基酸序列。其中3个片段的氨基酸序列与大鼠NF1-L的氨基酸序列一致，另一个片段的氨基酸序列与仓鼠NF1/Red1相同。在脊椎动物中，核因子1(NF1)家族蛋白至少由4个独立的基因编码，NF1-L和NF1/Red1分别来自不同的基因NFI-A和NFI-B。SF-A的显微测序显示，大鼠肝脏中至少存在两种类型的NF1。GAL4-融合蛋白在HepG2细胞中的功能分析表明，NFI-A代表了人金属硫蛋白IIA启动子的转录活性。我们的发现表明，多种形式的NF1家族结合到沉默区域，并参与GST-P基因表达的负调控。
We have previously identified a silencer region in the glutathione transferase P (GST-P) gene, of which the expression is completely repressed in liver of the rat. At least three trans-acting factors bind to multiple cis-elements in this region. Since GST-P silencer 4 (GSP4) is a dominant element in this silencer, we purified the GSP4 binding protein, called Silencer Factor A (SF-A). Purified SF-A was separated into several proteins on an SDS-polyacrylamide gel, and the amino acid sequences of four major components of SF-A were determined. The amino acid sequences of three fragments were identical to those of rat NF1-L, and that of the other fragment was the same as that of hamster NF1/Red1. It is known that nuclear factor 1 (NF1) family proteins are encoded by at least four independent genes in vertebrates, and NF1-L and NF1/Red1 are derived from different genes, NFI-A and NFI-B, respectively. The microsequencing of SF-A revealed that at least two types of NF1 existed in rat liver. Functional analysis by using GAL4-fusion protein in HepG2 cells revealed that NFI-A represented the transcription activity from human metallothionein IIA promoter. Our findings indicate that multiple forms of the NF1 family bind to the silencer region and contribute to the negative regulation of the GST-P gene expression.