Department of Biology, College of Sciences, Shiraz University, Shiraz 71454, Iran.
Biochem Biophys Res Commun. 2012 Oct 26;427(3):503-5. doi: 10.1016/j.bbrc.2012.09.085. Epub 2012 Sep 26.
Polymorphism of variable number of tandem repeats (VNTR) in the promoter region of X-ray repair cross-complementing 5 (XRCC5; MIM: 194364, rs6147172) has been reported. The main aim of the present study is to introduce a novel allele for the VNTR polymorphism in the promoter region of XRCC5. The participants of the present study were of 535 (140 males, 395 females), unrelated, adult, healthy Iranian blood donors (Caucasians/Muslims). Genotypes of XRCC5 VNTR were determined by a high resolution melting analysis, and confirmed by DNA sequencing. Based on the sequencing of new bands upper than the 2R allele band, a novel allele was introduced (named 3R allele). The promoter region of XRCC5 contains several copies of Sp1 recognition cis regulatory elements. The novel 3R allele is capable of expanding the number of cis regulatory elements to eight. The prevalence of the 0R, 1R, 2R and 3R alleles in our sample was 0.0645, 0.5439, 0.3794 and 0.0122, respectively. The study group was at the Hardy-Weinberg equilibrium for the genotypic frequencies (χ(2)=3.95, df=6, P=0.73). It is suggested that the prevalence of the novel allele (3R allele) among European populations may be higher than its prevalence among Iranians.
X 射线修复交叉互补基因 5（XRCC5；MIM：194364，rs6147172）启动子区的可变数目串联重复（VNTR）多态性已被报道。本研究的主要目的是介绍 XRCC5 启动子区 VNTR 多态性的一个新等位基因。本研究的参与者为 535 名（140 名男性，395 名女性），无亲缘关系，成年，健康的伊朗献血者（白种人/穆斯林）。XRCC5 VNTR 基因型通过高分辨率熔解分析确定，并通过 DNA 测序确认。基于比 2R 等位基因带高的新带的测序，引入了一个新的等位基因（命名为 3R 等位基因）。XRCC5 的启动子区含有几个 Sp1 识别顺式调控元件的拷贝。新的 3R 等位基因能够将顺式调控元件的数量扩展到八个。在我们的样本中，0R、1R、2R 和 3R 等位基因的流行率分别为 0.0645、0.5439、0.3794 和 0.0122。研究组在基因型频率上处于哈迪-温伯格平衡（χ(2)=3.95，df=6，P=0.73）。据推测，该新等位基因（3R 等位基因）在欧洲人群中的流行率可能高于在伊朗人群中的流行率。
