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| Author(s): |
Diana Santos Branco
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | Campinas, SP. |
| Institution: | Universidade Estadual de Campinas (UNICAMP). Instituto de Biologia |
| Defense date: | 2013-01-31 |
| Examining board members: |
Fernando Ferreira Costa;
Barry Htin Paw;
José Xavier Neto;
Gisele Wally Braga Colleoni;
Mônica Barbosa de Melo;
Maria Stella Figueiredo;
Erich Vinicius De Paula
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| Advisor: | Fernando Ferreira Costa; Anderson Ferreira da Cunha |
| Abstract | |
Molecular mechanisms involved in expression profile during erythropoiesis have been the subject of numerous investigations such study of gene regulation in erythroid cell culture. These studies allow us to identify new genes potentially involved in erythroid differentiation and additionally to investigate genes already known as regulators of red blood cells and hemoglobin production. Our research group identified several genes differentially expressed during erythropoiesis. Among them, the transcription factors, EYA3 and HES6 and the latexin, LX, were found to have higher expression in the final phase of the in vitro erythropoiesis. Our data suggest that EYA3 and LX, are involved in the intermediate and final stages of erythropoiesis, expression pattern of alfa and gama globin and HbF production in vitro. Additionally in zebrafish model, eya1, eya2, eya3, eya4, hes6 and hes13 showed a ubiquitous expression pattern, while lxn showed specific expression in the ICM, making it the most promising candidate to be knockdowned. lxn knockdown in zebrafish showed anemic phenotype at 72hpf embryos, but not at 48hpf, suggesting that the anemia results is due to a process in the end of the erythroid differentiation, corroborating the results found for in vitro cultures. Additional studies are necessary to understand the mechanisms and pathways involved in the participation of the LX, gene during the process of erythroid differentiation. CLPX, TRAK2 and GFI transcription factors are also potentially candidates to be involved in erythropoiesis. CLPX gene codes for caseinolytic peptidase X, a protein highly conserved during evolution, which presents an ATP-dependent chaperone function. Data from this study showed that clpx1 knockdown reduced significantly hemoglobinization levels and erythroid production in zebrafish. However, future studies xv for the clpx2 gene is needed to better understand the function of these genes in the heme production. TRAK2 gene, in turn, is a Trafficking Protein, Kinesin-Binding 2, involved in mitochondrial movement along microtubules. Results obtained in collaboration with the researcher Jeffrey Miller, M.D. (NIH/NIDDK), showed the involvement of this gene in erythropoiesis in primary culture in vitro models. In this study, from the orthologs for the human TRAK2 gene analyzed, only trak1.1 appears to have its function conserved in teleosts. The silencing of this gene generated anemic phenotype in the embryos tested, corroborating the original results obtained in primary cell culture. Finally, gfi1aa, gfi1ab and gfi1b zebrafish transcription factors, orthologous to the Grow Factor Independence (GFI) family transcription factors in humans, also had their function evaluated in hematopoiesis. Our data suggest is involved in the initial phase of hematopoiesis while gf1b has a role in the definite hematopoiesis. The epistatic relation between the gfi and the hematopoietic key transcription factors was also determined, showing that gfi1aa and gfi1b, together with lmo2, scl, runx-1 and c-myb also act as regulators of HSPC in teleosts (AU) | |