Identification and synergism of cis-acting elements essential for basal promoter activity of the human type 1 angiotensin II receptor gene in PLC-PRF-5 cells.
Identification and synergism of cis-acting elements essential for basal promoter activity of the human type 1 angiotensin II receptor gene in PLC-PRF-5 cells.
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DOI：
10.1507/endocrj.k06-187
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发表时间：
2007-07
影响因子：
2
通讯作者：
Seiko Shimoda;K. Ohnaka;Y. Sakai;H. Nawata;R. Takayanagi
中科院分区：
文献类型：
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作者：
Seiko Shimoda;K. Ohnaka;Y. Sakai;H. Nawata;R. Takayanagi
人类AT(1)受体基因的基础启动子活性是用具有相当高AT(1)表达的人肝癌细胞系PLC-PRF-5来表征的。鉴定出4个顺式正向调控元件AT(1)PRE1 （-113 ~ -102 bp）、AT(1)PRE2 （-49 ~ -43 bp）、AT(1)PRE3 （-5 ~ -2 bp）和AT(1)PRE4 （+44 ~ +50 bp）。AT(1)PRE2包含一个GC-box-like序列并与Sp1结合。AT(1)PRE1包含两个串联gc -box，除Sp1外还与多个核蛋白结合。在PLC-PRF-5细胞和8505C细胞中均发现了序列特异性结合AT(1)PRE1、AT(1)PRE2和AT(1)PRE4的核蛋白，而在8505C细胞中未发现与AT(1)PRE3结合的核蛋白，表明AT(1)基因不表达，AT(1)基因几乎没有启动子活性。即使AT(1)PRE1、AT(1)PRE2和AT(1)PRE4都发生突变，启动子活性仍然显著。然而，AT(1)PRE3的诱变实质上使启动子活性失活。AT(1)PRE1、AT(1)PRE2和AT(1)PRE4协同增强AT(1)PRE3促进的AT(1)基因转录。这些结果表明，AT(1)PRE3负责人类AT(1)基因的组织特异性表达，AT(1)PRE1、AT(1)PRE2和AT(1)PRE4在肝源性细胞中作为一般增强子起作用。
The basal promoter activity of the human AT(1) receptor gene was characterized using a human hepatoma cell line with a considerably high expression of AT(1), PLC-PRF-5. Four cis-acting, positively regulating elements termed AT(1)PRE1 (-113 to -102 bp), AT(1)PRE2 (-49 to -43 bp), AT(1)PRE3 (-5 to -2 bp) and AT(1)PRE4 (+44 to +50 bp) were identified. AT(1)PRE2 contained a GC-box-like sequence and bound to Sp1. AT(1)PRE1 contained two tandem GC-boxes and was bound to several nuclear proteins in addition to Sp1. Nuclear proteins that were bound sequence-specifically to AT(1)PRE1, AT(1)PRE2 and AT(1)PRE4 were found in both PLC-PRF-5 cells and 8505C cells, while those bound to AT(1)PRE3 were not found in 8505C cells, which showed no expression of AT(1) and almost no promoter activity for the AT(1) gene. Significant promoter activity was still observed even when AT(1)PRE1, AT(1)PRE2 and AT(1)PRE4 were all mutated. Mutagenesis of AT(1)PRE3, however, substantially inactivated promoter activity. AT(1)PRE1, AT(1)PRE2 and AT(1)PRE4 synergistically enhanced AT(1) gene transcription promoted by AT(1)PRE3. These results suggested that AT(1)PRE3 is responsible for the tissue-specific expression of the human AT(1) gene, and that AT(1)PRE1, AT(1)PRE2 and AT(1)PRE4 function as a general enhancer in liver-derived cells.