Full text
| |
| Author(s): |
Daniela Maria Ribeiro
Total Authors: 1
|
| Document type: | Doctoral Thesis |
| Press: | Campinas, SP. |
| Institution: | Universidade Estadual de Campinas (UNICAMP). Faculdade de Ciências Médicas |
| Defense date: | 2007-08-24 |
| Examining board members: |
Maria de Fátima Sonati;
Francisco M. Salzano;
Márcio José da Silva;
Mônica Barbosa de Melo;
Maricilda Palandi de Mello
|
| Advisor: | Maria de Fátima Sonati |
| Abstract | |
The expression of human a-like globin genes is regulated by the a-MRE (a-Major Regulatory Element), an element located 40 kb upstream of the a cluster in the short arm of chromosome 16. The a-MRE 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. The base substitutions that resulted in these haplotypes are located between binding sites for nuclear factors or in a site that is considered not to be active in vivo, with the exception of haplotype D, in which the polymorphism changes the first binding site for the NF-E2 factor occupied in vivo. To our knowledge, there are no experimental studies evaluating whether this variability may influence gene expression. Thus, the present work analyzed and compared the expression of the luciferase reporter gene in K562 cells transiently transfected with constructs that have, as enhancers, the different a-MRE haplotypes, besides three isolated polymorphisms (+130, +199 and +209). The results demonstrated a reduction in luciferase gene expression with all the constructs compared with the wild type a-MRE (A haplotype): the B and C haplotypes corresponded to 19% of the A haplotype expression, the D to 21%, the E to 15%, the F to 3%, the polymorphism +130 to 24%, the +199 to 32% and the +209 to 3%. They demonstrate that the polymorphisms responsible for the a-MRE haplotypes, most located in the flanking sequences of the regulatory protein binding sites, decrease in vitro gene expression (AU) | |