Human histamine N-methyltransferase pharmacogenetics:: Common genetic polymorphisms that alter activity
Human histamine N-methyltransferase pharmacogenetics:: Common genetic polymorphisms that alter activity
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DOI：
10.1124/mol.53.4.708
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发表时间：
1998-04-01
影响因子：
3.6
通讯作者：
Weinshilboum, RM
中科院分区：
文献类型：
--
作者：
Preuss, CV;Wood, TC;Weinshilboum, RM
组胺N-甲基转移酶（HNMT）催化组胺代谢的主要途径。人类HNMT活性水平受遗传调节。我们着手研究这种遗传调节的分子基础。北方印迹分析显示HNMT在肾脏中高度表达，因此我们测定了127个人肾活检样品中的酶活性和热稳定性水平。从12个具有广泛不同HNMT表型的肾脏样品中分离DNA，并用聚合酶链反应扩增HNMT基因的外显子。在这12个样品中，我们观察到C314 T转换，导致编码氨基酸的Thr 105 Ile变化，以及3 '非翻译区内的A939 G转换。然后对所有剩余的肾活检样本进行这两种变异序列的基因分型。在114个研究样本中，编码Thr 105和Ile 105的等位基因的频率分别为0.90和0.10，而核苷酸A939和G等位基因的频率分别为0.79和0.21，具有编码Ile 105的等位基因的肾脏样品的HNMT活性和热稳定性水平显著低于具有编码Thr 105的等位基因的肾脏样品。这些观察结果得到了证实，在COS-1细胞的瞬时表达的构建体，含有所有四个等位基因的这两个多态性。转染Ile 105等位基因的COS-1细胞的HNMT活性和免疫反应性HNMT蛋白显著低于转染Thr 105等位基因的COS-1细胞。这些观察结果将有可能检验HNMT的遗传多态性可能在人类疾病的病理生理学中发挥作用的假设。
Histamine N-methyltransferase (HNMT) catalyzes a major pathway in histamine metabolism. Levels of HNMT activity in humans are regulated by inheritance. We set out to study the molecular basis for this genetic regulation. Northern blot analysis showed that HNMT is highly expressed in the kidney, so we determined levels of enzyme activity and thermal stability in 127 human renal biopsy samples. DNA was isolated from 12 kidney samples with widely different HNMT phenotypes, and exons of the HNMT gene were amplified with the polymerase chain reaction. In these 12 samples, we observed a C314T transition that resulted in a Thr105Ile change in encoded amino acid, as well as an A939G transition within the 3'-untranslated region. All remaining renal biopsy samples then were genotyped for these two variant sequences. Frequencies of the alleles encoding Thr105 and Ile105 in the 114 samples studied were 0.90 and 0.10, respectively, whereas frequencies for the nucleotide A939 and G alleles were 0.79 and 0.21, respectively, Kidney samples with the allele encoding Ile105 had significantly lower levels of HNMT activity and thermal stability than did those with the allele that encoded Thr105. These observations were confirmed by transient expression in COS-1 cells of constructs that contained all four alleles for these two polymorphisms. COS-1 cells transfected with the Ile105 allele had significantly lower HNMT activity and immunoreactive HNMT protein than did those transfected with the Thr105 allele. These observations will make it possible to test the hypothesis that genetic polymorphisms for HNMT may play a role in the pathophysiology of human disease.