Teh L K, Lee W L, Amir J, Salleh M Z, Ismail R
Faculty of Pharmacy, Universiti Teknologi MARA, 41050 Shah Alam, Malaysia.
J Clin Pharm Ther. 2007 Jun;32(3):313-9. doi: 10.1111/j.1365-2710.2007.00822.x.
P-glycoprotein (PgP) is the most extensively studied ATP-binding cassette (ABC) coded by MDR1 gene. To date, 29 single nucleotide polymorphisms (SNPs) have been identified; but only SNP C3435T has been correlated with intestinal PgP expression levels and shown to influence the absorption of orally taken drugs that are PgP substrates. Individuals homozygous for the T allele have more than fourfold lower PgP expression compared with C/C individuals. We developed a one step primer based allele specific PCR method to detect SNP at C3435T to investigate the distribution of this genotype in the local population.
DNA was extracted from 5 mL of whole blood using standard salting-out method. Primers were designed specific to 3' end which amplify the variants of C3435T. The method was validated by direct DNA sequencing. Seven hundred and sixty-three healthy blood donors comprising of three major ethnic groups in Malaysia were recruited and DNA subjected to genotyping of C3435T using this method.
The method was found to be robust and reproducible in detecting SNP of C3435T. Interethnic variations in genotype and allele frequency were observed in PgP among the ethnic groups. In comparison to both the Caucasians and the other Asian countries, the Malay and Chinese showed a higher frequency of allele C (50-60%); while the Indian exhibits a lower frequency (40%), similar to other Indian populations.
Using a new simple method to investigate the distribution of C3435T, we found that the allele frequency of MDR1 showed variablity between the different ethnic groups within the Malaysian population.
P-糖蛋白（PgP）是由多药耐药基因1（MDR1）编码的研究最为广泛的ATP结合盒转运蛋白（ABC）。迄今为止，已鉴定出29个单核苷酸多态性（SNP）；但只有SNP C3435T与肠道PgP表达水平相关，并显示会影响口服PgP底物药物的吸收。与C/C个体相比，T等位基因纯合个体的PgP表达降低四倍以上。我们开发了一种基于一步引物的等位基因特异性PCR方法来检测C3435T处的SNP，以研究该基因型在当地人群中的分布。
采用标准盐析法从5 mL全血中提取DNA。设计3'端特异性引物以扩增C3435T的变体。该方法通过直接DNA测序进行验证。招募了763名马来西亚三个主要种族的健康献血者，并使用该方法对C3435T进行基因分型。
该方法在检测C3435T的SNP方面具有稳健性和可重复性。在不同种族的PgP中观察到基因型和等位基因频率的种族间差异。与白种人和其他亚洲国家相比，马来人和华人的等位基因C频率较高（50 - 60%）；而印度人的频率较低（40%），与其他印度人群相似。
使用一种新的简单方法来研究C3435T的分布，我们发现MDR1的等位基因频率在马来西亚人群的不同种族之间存在差异。
