[Polymorphism in BP1 binding site upstream of β-globin gene in Chinese Han population]

This study was aimed to analyze the BP1 binding site sequence upstream of β-globin gene in Chinese Han population, and to investigate polymorphism in the BP1 binding site upstream of β-globin gene, so as to provide the basis for exploration of relation between polymorphisms in the BP1 binding site and β-globin expression. Genomic DNA was extracted from peripheral leukocytes of 110 healthy individuals in Chinese Han population. Sequence of the BP1 binding site upstream of β-globin gene was amplified by polymerase chain reaction, the polymorphic variation in the BP1 binding site was determined by DNA sequencing. The results indicated that 2 polymorphism loci were found in the BP1 binding site upstream of β-globin gene, they were C/T at the -551 bp region and (AC)(n)(AT)(x)T(y) at the -530 bp region in Chinese Han population. Frequencies of C and T were 60.4% and 39.6% at position -551. Analysis of the (AC)(n)(AT)(x)T(y) polymorphism revealed 9 different genotypes: (AC)(2)(AT)(9)T(5), (AC)(2)(AT)(8)T(5), (AC)(2)(AT)(7)T(7), (AC)(3)(AT)(7)T(5), (AC)(2)(AT)(8)T(9), (AC)(3)(AT)(8)T(5), (AC)(2)(AT)(10)T(3), (AC)(2)(AT)(11)T(3), and (AC)(2)(AT)(7)T(5) at position -530. Frequencies of 9 (AC)(n)(AT)(x)T(y) polymorphisms were 33.2%, 29.1%, 24.1%, 5.4%, 3.2%, 1.8%, 1.4%, 0.9%, and 0.9% respectively. It is concluded that rich (AC)(n)(AT)(x)T(y) polymorphisms at the -530 bp region in the BP1 binding site upstream of β-globin gene are found in Chinese Han population. (AC)(2)(AT)(9)T(5), (AC)(2)(AT)(8)T(5), and (AC)(2)(AT)(7)T(7) are 3 major polymorphisms among Chinese Han population, and (AC)(3)(AT)(8)T(5) is a novel polymorphism at the -530 bp region. More studies should be done to explore relation between (AC)(n)(AT)(x)T(y) polymorphisms and β-globin expression.