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Type: Artigo de periódico
Title: Influence Of The Polymorphisms Of The Alpha-major Regulatory Element Hs-40 On In Vitro Gene Expression.
Author: Ribeiro, D M
Zaccariotto, T R
Santos, M N N
Costa, F F
Sonati, M F
Abstract: The alpha-MRE is the major regulatory element responsible for the expression of human alpha-like globin genes. It is genetically polymorphic, and six different haplotypes, named A to F, have been identified in some population groups from Europe, Africa and Asia and in native Indians from two Brazilian Indian tribes. Most of the mutations that constitute the alpha-MRE haplotypes are located in flanking sequences of binding sites for nuclear factors. To our knowledge, there are no experimental studies evaluating whether such variability may influence the alpha-MRE enhancer activity. We analyzed and compared the expression of luciferase of nine constructs containing different alpha-MRE elements as enhancers. Genomic DNA samples from controls with A (wild-type alpha-MRE) and B haplotypes were used to generate C-F haplotypes by site-directed mutagenesis. In addition, three other elements containing only the G-->A polymorphism at positions +130, +199, and +209, separately, were also tested. The different alpha-MRE elements were amplified and cloned into a plasmid containing the luciferase reporter gene and the SV40 promoter and used to transiently transfect K562 cells. A noticeable reduction in luciferase expression was observed with all constructs compared with the A haplotype. The greatest reductions occurred with the F haplotype (+96, C-->A) and the isolated polymorphism +209, both located near the SP1 protein-binding sites believed not to be active in vivo. These are the first analyses of alpha-MRE polymorphisms on gene expression and demonstrate that these single nucleotide polymorphisms, although outside the binding sites for nuclear factors, are able to influence in vitro gene expression.
Subject: Gene Expression Regulation
K562 Cells
Polymorphism, Genetic
Regulatory Elements, Transcriptional
Citation: Brazilian Journal Of Medical And Biological Research = Revista Brasileira De Pesquisas Médicas E Biológicas / Sociedade Brasileira De Biofísica ... [et Al.]. v. 42, n. 9, p. 783-6, 2009-Sep.
Rights: aberto
Identifier DOI: 
Date Issue: 2009
Appears in Collections:Unicamp - Artigos e Outros Documentos

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