| Research Abstract |
To understand functional roles that GATA factors play during erythroid cell differentiation, we examined the expression of GATA factors at both mRNA and protein levels. We also examined the structure of the genes encoding GATA factors. The results of expression analysis of GATA factors in leukemia-derived cell lines suggest that GATA-1 is essential for the development of erythroid/megakaryocytic cells, whereas GATA-2 is important for much earlier stage of cells in hematopoietic lineage. To define which GATA factor actually binds to a particular GATA sequence in vivo, we isolated DNA/GATA-1 complex from nuclei of mouse erythroleukemia cells by using anti-GATA-1 monoclonal antibody. We found genes which are expressed specifically in erythroid lineage cells in the immunoprecipitate. In contrast, we could not find genes which have GATA sites but are expressed in cells different from erythroid lineage. This finding indicates that GATA-1 binds only to the GATA sequences in the regulatory region for erythroid genes and suggests that GATA-1 is important for erytyroid gene expression. We found that GATA-1 is also expressed in mouse testis. Whereas the primary structure of this factor is completely the same as that in erythroid cells, the expression of testis form GATA-1 mRNA was found to be driven by the testis-specific promoter. We determined human GATA-2 and chicken GATA-3 genes, and found that the organization of these genes are very well conserved between species and between each GATA factor. Based on these results, we concluded that GATA factors function as regulators of thissue-specific gene expression.
|
