title: Electromobility Shift Assay Reveals Evidence in Favor of Allele-Specific Binding of RUNX1 to the 5' Hypersensitive Site 4-Locus Control Region.
abstract: In our previous studies on the Iranian β-thalassemia (β-thal) patients, we identified an association between the severity of the β-thal phenotype and the polymorphic palindromic site at the 5' hypersensitive site 4-locus control region (5'HS4-LCR) of the β-globin gene cluster. Furthermore, a linkage disequilibrium was observed between this region and XmnI-HBG2 in the patient population. Based on this data, it was suggested that the well-recognized phenotype-ameliorating role assigned to positive XmnI could be associated with its linked elements in the LCR. To investigate the functional significance of polymorphisms at the 5'HS4-LCR, we studied its influence on binding of transcription factors. Web-based predictions of transcription factor binding revealed a binding site for runt-related transcription factor 1 (RUNX1), when the allele at the center of the palindrome (TGGGG(A/G)CCCCA) was A but not when it was G. Furthermore, electromobility shift assay (EMSA) presented evidence in support of allele-specific binding of RUNX1 to 5'HS4. Considering that RUNX1 is a well-known regulator of hematopoiesis, these preliminary data suggest the importance of further studies to confirm this interaction and consequently investigate its functional and phenotypical relevance. These studies could help us to understand the molecular mechanism behind the phenotype modifying role of the 5'HS4-LCR polymorphic palindromic region (rs16912979), which has been observed in previous studies.
authors: a Genetics Research Center, University of Social Welfare and Rehabilitation Sciences , Tehran , Iran.
authors: Hossein
authors: H
authors: Dehghani
authors: a Genetics Research Center, University of Social Welfare and Rehabilitation Sciences , Tehran , Iran.
authors: Sepideh
authors: S
authors: Ghobakhloo
authors: a Genetics Research Center, University of Social Welfare and Rehabilitation Sciences , Tehran , Iran.
authors: Maryam
authors: M
authors: Neishabury
mesh_terms: D000483:Alleles; D001665:Binding Sites; D050676:Core Binding Factor Alpha 2 Subunit / Q000378:metabolism*; D024202:Electrophoretic Mobility Shift Assay; D006801:Humans; D055029:Inverted Repeat Sequences; D019901:Locus Control Region; D010641:Phenotype; D011485:Protein Binding
chemical_list: D050676:Core Binding Factor Alpha 2 Subunit
keywords: 5′ hypersensitive site 4-LCR (5′HS4-LCR); RUNX1 (runt-related transcription factor 1); XmnI-HBG2; chromatin looping; hemoglobin (Hb) switching; phenotype modifying factors; polymorphic-palindromic region; thalassemia; β-Globin locus control region (LCR)