Six novel UDP-glucuronosyltransferase (UGT1A3) polymorphisms with varying activity
Six novel UDP-glucuronosyltransferase (UGT1A3) polymorphisms with varying activity
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DOI：
10.1007/s10038-003-0119-y
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发表时间：
2004-03-01
影响因子：
3.5
通讯作者：
Takeuchi, Y
中科院分区：
文献类型：
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作者：
Iwai, M;Maruo, Y;Takeuchi, Y
人 UDP-葡萄糖醛酸基转移酶 (UGT) 是内生素和异生素主要排泄途径的一部分。 UGT 基因家族具有高度多态性，我们的目标是描述 UGT1A3 基因座的新多态性，并确定它们如何改变底物代谢和药物反应。一百名健康的日本成年人自愿参加本研究。我们直接对 PCR 扩增的基因片段进行测序，并计算检测到的遗传变异的频率。为了测量变异酶的活性，我们构建了五种表达模型，并在测定中使用雌酮作为底物。我们鉴定了六种新的单核苷酸多态性 (SNP)。其中，四个引起氨基酸取代（17A-->G：Q6R、31T-->C：W11R、133C-->T：R45W和140T-->C：V47A），其余两个是沉默的（81G-->A：E27E和447A-->G：A159A）。我们发现了五种具有不同SNP组合的等位基因：野生型（频率=0.61）、W11R-E27E-A159A（0.10）、Q6A-W11R-E27E-A159A（0.055）、W11R-E27E-V47A-A159A（0.125）和R45W（0.11）。表达研究发现，这些变体将 W11R 的酶效率 (K-m/V-max) 更改为野生型的 121%，Q6R-W11R 为 86%，W11R-V47A 为 369%，R45W 为 70%。日本人群中存在多种 UGT 1A3 多态性，具有不同的活性水平。这些多态性能够影响雌激素的稳态水平，并可能增加对药物不良反应的敏感性。
Human UDP-glucuronosyltransferase (UGT) is a part of a major excretion pathway for endobiotics and xenobiotics. The UGT family of genes is highly polymorphic, and our aim is to describe novel polymorphisms at the UGT1A3 locus and determine how they alter substrate metabolism and drug reactions. One hundred healthy Japanese adults volunteered for the present study. We sequenced PCR-amplified fragments of the gene directly, and calculated the frequency of the genetic variations detected. To measure variant enzyme activity, we constructed five expression models and used estrone as the substrate in the assays. We identified six novel single nucleotide polymorphisms (SNPs). Of these, four caused amino acid substitutions (17A-->G: Q6R, 31T-->C: W11R, 133C-->T: R45W, and 140T-->C: V47A) and the remaining two were silent (81G-->A: E27E and 447A-->G: A159A). We found five types of alleles having differing SNP combinations: wild type (frequency=0.61), W11R-E27E-A159A (0.10), Q6A-W11R-E27E-A159A (0.055), W11R-E27E-V47A-A159A (0.125), and R45W (0.11). Expression studies found that the variants changed the enzyme efficiencies (K-m/V-max) to 121% of the wild type for W11R, 86% for Q6R-W11R, 369% for W11R-V47A, and 70% for R45W. Several UGT 1A3 polymorphisms exist in the Japanese population, having different levels of activity. These polymorphisms are capable of affecting the steady state levels of estrogens, and may increase sensitivity to adverse drug effects.