Functional polymorphism in ALOX15 results in increased allele‐specific transcription in macrophages through binding of the transcription factor SPI1
Functional polymorphism in ALOX15 results in increased allele‐specific transcription in macrophages through binding of the transcription factor SPI1
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DOI：
10.1002/humu.20273
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发表时间：
2006-01
期刊：
影响因子：
3.9
通讯作者：
J. Wittwer;Jacqueline Marti‐Jaun;M. Hersberger
中科院分区：
文献类型：
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作者：
J. Wittwer;Jacqueline Marti‐Jaun;M. Hersberger
网织红细胞15-脂氧合酶-1(ALOX15)具有抗炎和炎症作用，与哮喘、关节炎和动脉粥样硬化的发生有关。我们筛选了人类ALOX15基因的变异，因为ALOX15的遗传变异可能会影响这些疾病。我们检测到11个变异，其中5个位于ALOX15启动子区域。其中一种多态，即c.−第292位的C-T替换，为SPI1创造了一个新的转录因子结合位点。转录实验表明，带有c.−292 T的启动子变异体的转录效率是所有含有c.−292C的启动子变异体的两倍。这在结构性表达SPI1的巨噬细胞中是正确的，但在不表达SPI1的肺上皮细胞系中则不是。SPI1核心结合位点的突变取消了较高的转录活性，凝胶迁移率改变分析表明，SPI1选择性地与突变的c.292T和c.−292C启动子结合。这些结果在原代人巨噬细胞中得到证实，杂合子c.−292CT携带者的巨噬细胞表达的ALOX15mRNA是纯合子c.−292CC携带者巨噬细胞的3倍。我们的结论是，ALOX15启动子中的c.-292 T等位基因为转录因子SPI1产生了一个新的结合位点，从而导致该基因在巨噬细胞中的高转录。这可能导致ALOX15介导的脂代谢产物增加，后者在炎症中发挥作用。嗡嗡作响27(1)，78-87,2006。©2005 Wiley-Liss Inc.
The reticulocyte‐type 15‐lipoxygenase‐1 (ALOX15) has antiinflammatory and inflammatory effects, and is implicated in the development of asthma, arthritis, and atherosclerosis. We screened the human ALOX15 gene for variations because genetic variability in ALOX15 may influence these diseases. We detected 11 variations, including five polymorphisms located in the ALOX15 promoter region. One of these polymorphisms, a C‐to‐T substitution at position c.−292, created a novel transcription factor binding site for SPI1. Transcription assays revealed that promoter variants with c.−292 T transcribe twice as efficiently as all the other promoter variants containing c.−292C. This was true in macrophages that constitutively express SPI1, but not in a lung epithelial cell line that does not express SPI1. Mutation of the core‐binding site for SPI1 abolished the higher transcriptional activity, and electrophoretic mobility shift assays showed that SPI1 selectively binds to the mutant c.–292 T and c.−292C promoter. These results were corroborated in primary human macrophages, in which macrophages from heterozygous c.−292CT carriers expressed three times more ALOX15 mRNA than macrophages from homozygous c.−292CC carriers. We conclude that the c.–292 T allele in the ALOX15 promoter generates a novel binding site for the transcription factor SPI1 that results in higher transcription of the gene in macrophages. This may lead to an increase in ALOX15‐mediated lipid metabolites, which play a role in inflammation. Hum Mutat 27(1), 78–87, 2006. © 2005 Wiley‐Liss, Inc.