Influence of the polymorphisms of the alpha-major regulatory element HS-40 on in vitro gene expression
Braz. j. med. biol. res
; 42(9): 783-786, Sept. 2009. graf, tab
Article
en En
| LILACS
| ID: lil-524320
Biblioteca responsable:
BR1.1
ABSTRACT
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.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Base de datos:
LILACS
Asunto principal:
Polimorfismo Genético
/
Haplotipos
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Globinas
/
Regulación de la Expresión Génica
/
Elementos Reguladores de la Transcripción
/
Mutación
Tipo de estudio:
Prognostic_studies
Límite:
Humans
Idioma:
En
Revista:
Braz. j. med. biol. res
Asunto de la revista:
BIOLOGIA
/
MEDICINA
Año:
2009
Tipo del documento:
Article
/
Project document
País de afiliación:
Brasil
Pais de publicación:
Brasil