nfluence of the polymorphisms of the α-major regulatory element HS-40 on in vitro gene expression

Autor(es)

D.M. Ribeiro ; T.R. Zaccariotto ; M.N.N. Santos ; F.F. Costa ; M.F. Sonati

• Tipo de documento: Artigo Científico
• Fonte: Brazilian Journal of Medical and Biological Research; v. 42, n. 9, p. 783-786, Set. 2009.
• Assunto(s): Polimorfismo genético

Resumo

The α-MRE is the major regulatory element responsible for the expression of human α-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 α-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 α-MRE enhancer activity. We analyzed and compared the expression of luciferase of nine constructs containing different α-MRE elements as enhancers. Genomic DNA samples from controls with A (wild-type α-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 α-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 α-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. (AU)

• Processo FAPESP: 02/13801-7 - Alterações hereditárias das hemoglobinas: genética molecular, aspectos da evolução clínica e produção de animais transgênicos
• Beneficiário: Fernando Ferreira Costa
• Linha de fomento: Auxílio à Pesquisa - Temático
• Processo FAPESP: 03/07412-0 - Influência dos haplótipos do elemento regulatório do cluster alfa na expressão dos genes da globina alfa humana
• Beneficiário: Daniela Maria Ribeiro
• Linha de fomento: Bolsas no Brasil - Doutorado