An artifact derived from a pseudogene led to the discovery of microRNA binding site polymorphism in the 3'-untranslated region of the human dihydrofolate reductase gene.
A novel single-nucleotide polymorphism (SNP) in the 3'-untranslated region of the human dihydrofolate reductase (DHFR) gene with enhanced expression was identified in 2001. In 2007, it was reported that this SNP, DHFR C829T, was located close to a microRNA binding site and contributed to the stability of mRNA. Many researchers have analyzed this SNP in several races including Asians and Caucasians. However, the mutation allele is not yet confirmed in most populations. In this study, we reinvestigated the frequency of this SNP using three methods. First, this SNP in genomic DNA was analyzed by a PCR-restriction fragment length polymorphism method. Second, this SNP in mRNA was analyzed by a single nucleotide extension method following a reverse transcription reaction. Third, the mRNA expression level was analyzed by a real-time PCR method. The findings in our study, regarding the discovery of this SNP, suggest that the SNP is an artifact caused by contamination by the genomic DNA of the pseudogene DHFRP1. This study is a reinvestigation of a newly discovered genetic polymorphism.
Department of Clinical Pharmacology & Genetics, School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka.
Hideki
H
Hayashi
Yui
Y
Tazoe
Masato
M
Horino
Chihiro
C
Fujimaki-Katoh
Seiji
S
Tsuboi
Taiji
T
Matsuyama
Kazuhiro
K
Kosuge
Hiroshi
H
Yamada
Daiki
D
Tsuji
Kazuyuki
K
Inoue
Kunihiko
K
Itoh
D020413:3' Untranslated Regions / Q000235:genetics*; D016477:Artifacts; D044466:Asian People / Q000235:genetics*; D001665:Binding Sites / Q000502:physiology; D006801:Humans; D035683:MicroRNAs / Q000235:genetics* / Q000378:metabolism; D020641:Polymorphism, Single Nucleotide / Q000235:genetics*; D011544:Pseudogenes / Q000235:genetics*; D013762:Tetrahydrofolate Dehydrogenase / Q000235:genetics* / Q000378:metabolism
D020413:3' Untranslated Regions; D035683:MicroRNAs; D013762:Tetrahydrofolate Dehydrogenase