A nucleotide insertion in the transcriptional regulatory region of FADS2 gives rise to human fatty acid delta-6-desaturase deficiency
A nucleotide insertion in the transcriptional regulatory region of FADS2 gives rise to human fatty acid delta-6-desaturase deficiency
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DOI：
10.1194/jlr.m300273-jlr200
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发表时间：
2003-12-01
影响因子：
6.5
通讯作者：
Domann, FE
中科院分区：
文献类型：
--
作者：
Nwankwo, JO;Spector, AA;Domann, FE
脂肪酸δ-6-去饱和酶（FADS 2）是哺乳动物合成长链多不饱和脂肪酸的限速酶。我们研究了皮肤成纤维细胞中FADS 2缺乏的分子机制，该酶缺乏的患者。表达分析表明，与正常对照组相比，患者来源的细胞中FADS 2 mRNA的稳态水平降低了80%至90%，这与先前的代谢生化研究一致。体外转录测定表明，患者来源的细胞中的转录起始速率降低了80%，从而暗示转录调控是转录水平降低的机制。对该基因5'端的序列分析表明，与正常细胞和已发表的序列相比，在患者来源的细胞中，在翻译起始位点上游的-941和-942位置之间插入了胸苷。启动子-报告基因分析表明，与正常基因相比，多态性变体FADS 2调控区的启动子活性降低了6倍，证实了插入突变与患者来源细胞中基因表达降低的功能相关性。这些发现表明，脂肪酸δ-6-去饱和酶缺乏和FADS 2转录降低是由人FADS 2基因转录调控区中的核苷酸插入引起的。Nwankwo，J. O.，A. A. Spector和E.多曼在FADS 2的转录调控区中的核苷酸插入引起人脂肪酸δ-6-去饱和酶缺乏。
Fatty acid delta-6-desaturase (FADS2) is the rate-limiting enzyme in mammalian synthesis of long-chain polyunsaturated fatty acids. We investigated the molecular mechanism of FADS2 deficiency in skin fibroblasts from a patient deficient in this enzyme. Expression analyses demonstrated an 80% to 90% decrease in the steady-state level of FADS2 mRNA in patient-derived cells compared with normal controls that was consistent with previous metabolic biochemical studies. In vitro transcription assays indicated an 80% decrease in the rate of transcriptional initiation in patient-derived cells, thus implicating transcriptional regulation as the mechanism for the decreased transcript levels. Sequence analysis of the 5' end of the gene revealed the insertion of a thymidine between positions -941 and -942 upstream of the translation start site in patient-derived cells compared with normal cells and published sequences. Promoter-reporter assays demonstrated a 6-fold decrease in promoter activity in the polymorphic variant FADS2 regulatory region compared with the normal gene, confirming the functional relevance of the insertion mutation to the decreased expression of the gene in the patient-derived cells. These findings indicate that fatty acid delta-6-desaturase deficiency and decreased FADS2 transcription are caused by a nucleotide insertion in the transcriptional regulatory region of the human FADS2 gene.-Nwankwo,J. O., A. A. Spector, and E E. Domann. A nucleotide insertion in the transcriptional regulatory region of FADS2 gives rise to human fatty acid delta-6-desaturase deficiency.