TY - JOUR
T1 - Human histamine N-methyltransferase pharmacogenetics
T2 - Gene resequencing, promoter characterization, and functional studies of a common 5′-flanking region single nucleotide polymorphism (SNP)
AU - Wang, Liewei
AU - Thomae, Bianca
AU - Eckloff, Bruce
AU - Wieben, Eric
AU - Weinshilboum, Richard
N1 - Funding Information:
We thank Mrs. Luanne Wussow for her assistance with the preparation of this manuscript. This work was supported, in part, by NIH Grants RO1 GM28157, RO1 GM35720, and UO1 GM61388.
PY - 2002/8/15
Y1 - 2002/8/15
N2 - Histamine N-methyltransferase (HNMT) catalyzes one of two major metabolic pathways for histamine. The levels of HNMT activity and immunoreactive protein in human tissues are regulated primarily by inheritance. Previous studies of HNMT identified two common single nucleotide polymorphisms (SNPs), including a functionally significant nonsynonymous coding SNP (cSNP), (C314T, Thr105Ile), but that polymorphism did not explain all of the phenotypic variation. In the present study, a genotype-to-phenotype strategy was used to search for additional genetic factors that might contribute to the regulation of human HNMT activity. Specifically, we began by resequencing the human HNMT gene using 90 ethnically anonymous DNA samples from the Coriell Cell Repository and identified a total of eight SNPs, including the two that had been reported previously. No new nonsynonymous cSNPs were observed, but three of the six novel SNPs were located in the 5′-flanking region (5′-FR) of the gene - including a third common polymorphism with a frequency of 0.367 (36.7%). That observation directed our attention to possible genetic effects on HNMT transcription. As a first step in testing that possibility, we created and studied a series of reporter gene constructs for the initial 1kb of the HNMT 5′-FR. The core promoter and possible regulatory regions were identified and verified by electrophoresis mobility shift assays. We then studied the possible functional implications of the new common HNMT 5′-FR SNP. However, on the basis of reporter gene studies, that SNP appeared to have little effect on transcription. Phenotype-genotype correlation analysis performed with 112 human kidney biopsy samples that had been phenotyped for their level of HNMT activity confirmed that the common 5′-FR SNP was not associated with the level of HNMT activity in vivo. In summary, this series of experiments resulted in the identification of several novel HNMT polymorphisms, identification of the HNMT core promoter, and a comprehensive functional genomic study of a common HNMT 5′-FR SNP. These results represent an additional step in the definition of molecular genetic mechanisms involved in the regulation of this important autacoid-metabolizing enzyme in humans.
AB - Histamine N-methyltransferase (HNMT) catalyzes one of two major metabolic pathways for histamine. The levels of HNMT activity and immunoreactive protein in human tissues are regulated primarily by inheritance. Previous studies of HNMT identified two common single nucleotide polymorphisms (SNPs), including a functionally significant nonsynonymous coding SNP (cSNP), (C314T, Thr105Ile), but that polymorphism did not explain all of the phenotypic variation. In the present study, a genotype-to-phenotype strategy was used to search for additional genetic factors that might contribute to the regulation of human HNMT activity. Specifically, we began by resequencing the human HNMT gene using 90 ethnically anonymous DNA samples from the Coriell Cell Repository and identified a total of eight SNPs, including the two that had been reported previously. No new nonsynonymous cSNPs were observed, but three of the six novel SNPs were located in the 5′-flanking region (5′-FR) of the gene - including a third common polymorphism with a frequency of 0.367 (36.7%). That observation directed our attention to possible genetic effects on HNMT transcription. As a first step in testing that possibility, we created and studied a series of reporter gene constructs for the initial 1kb of the HNMT 5′-FR. The core promoter and possible regulatory regions were identified and verified by electrophoresis mobility shift assays. We then studied the possible functional implications of the new common HNMT 5′-FR SNP. However, on the basis of reporter gene studies, that SNP appeared to have little effect on transcription. Phenotype-genotype correlation analysis performed with 112 human kidney biopsy samples that had been phenotyped for their level of HNMT activity confirmed that the common 5′-FR SNP was not associated with the level of HNMT activity in vivo. In summary, this series of experiments resulted in the identification of several novel HNMT polymorphisms, identification of the HNMT core promoter, and a comprehensive functional genomic study of a common HNMT 5′-FR SNP. These results represent an additional step in the definition of molecular genetic mechanisms involved in the regulation of this important autacoid-metabolizing enzyme in humans.
KW - Genotype-phenotype correlation analysis
KW - HNMT
KW - Histamine
KW - Histamine N-methyltransferase
KW - Methylation
KW - SNPs
KW - Single nucleotide polymorphism
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U2 - 10.1016/S0006-2952(02)01223-6
DO - 10.1016/S0006-2952(02)01223-6
M3 - Article
C2 - 12167489
AN - SCOPUS:0037103556
SN - 0006-2952
VL - 64
SP - 699
EP - 710
JO - Biochemical Pharmacology
JF - Biochemical Pharmacology
IS - 4
ER -