GATA-1 is a hematopoietic transcription factor that is essential for the terminal maturation of proerythroblasts, megakaryocytic cells and mast cells. The erythroid-specific promoter of the human GATA-1 gene directs t...GATA-1 is a hematopoietic transcription factor that is essential for the terminal maturation of proerythroblasts, megakaryocytic cells and mast cells. The erythroid-specific promoter of the human GATA-1 gene directs the high expression of a reporter gene in K562 cells. Multiple putative transcription factor binding sites were identified in the promoter from the -860 to the -1 base pair （bp）. For a better understanding of the transcriptional control of human GATA-1 gene expression, we tested the transcriptional activity of a series of deletions from the 5′ end of the 860-bp promoter. A region between -221 and -128 bp retains most of the transcriptional activity of the full-length promoter. Deletion of the CGCCC box at-195 bp reduced reporter gene activity to 60.4%. Further deletion of the CACCC box at -173 bp nearly abolished reporter gene expression, indicating that the CACCC box is more critical. In vitro experiments of electrophoretic mobility shifts and in vivo studies using chromatin immuno-precipitation （CHIP） assays show that the Sp1/Sp3 proteins bind the CACCC site in the nuclei of K562 cells. Coincidently, hyperacetylation of histones in the GATA-1 erythroid promoter was also shown by ChIP assay. Co-transfection of Spl expression plasmids and plasmids with a wild-type promoter showed enhanced reporter gene activity in a dose-dependent manner. The combined data demonstrate that Sp1/Sp3, but not EKLF, is involved in the activation of the GATA-1 erythroid promoter, and that histones H3 and H4 are highly acetylated in this promoter region for an actively transcribed GATA-1 gene in K562 cells in which EKLF is barely detectable.展开更多
An Amh promoter driving expression of a reporter gene (d2EGFP) has been used to analyze the role of two specific promoter transcription factor binding elements. In addition a downstream (3’) enhancer (DE) was also in...An Amh promoter driving expression of a reporter gene (d2EGFP) has been used to analyze the role of two specific promoter transcription factor binding elements. In addition a downstream (3’) enhancer (DE) was also investigated. The transcription factors GATA-1 and GATA-4 had opposite effects, the former being incremental and the latter decremental. The quantitative balance between these two factors may provide a degree of control over the level of gene expression.展开更多
Objective： The aim of the study was to investigate the expression pattern of hematopoietic transcription factor GATA-1, -2 and -3 genes in leukemic bone marrow （BM） micreenvironment [including bone marrow stremal c...Objective： The aim of the study was to investigate the expression pattern of hematopoietic transcription factor GATA-1, -2 and -3 genes in leukemic bone marrow （BM） micreenvironment [including bone marrow stremal cells （BMSCs） and BM hematopoietic cells]. Methods： Mononuclear cells were isolated from BM of patients with acute myeloid leukemia （AML）, chronic myelogenous leukemia （CML）, or acute lymphoblasUc leukemia （ALL）. Adherent cells （BMSCs） and nonadherent ceils （BM hematopoietic cells） were collected after long-term culture in vitro. The semi-quantitative expression levels of GATA genes in the BMSCs or BM hematopoietic cells from patients with leukemia were analyzed by using RT-PCR-ELISA and com- pared with normal controls. Results： The expression level of GATA-1 gene in the BMSCs from CML group was significantly lower than that of the normal controls. The expression level of GATA-3 gene in the BMSCs from ALL was higher than that of the normal controls, but that from CML was lower than the normal controls. Dominant expression of GATA-3 gene was found in the normal BM hematopoietic cells. The dominant expression of GATA-2 gene was found in the normal BMSCs and the BMSCs from CML, whereas the dominant expression of GATA-3 gene was detected in the BMSCs from AML. Conclusion： GATA-1, -2 and -3 genes might play a role in hematopoiesis regulation in leukemia, and the changes of expression pattern of GATA genes might influence the hematopoiesis in BM microenvironment and relate to the pathogenesis and development of leukemia.展开更多
文摘GATA-1 is a hematopoietic transcription factor that is essential for the terminal maturation of proerythroblasts, megakaryocytic cells and mast cells. The erythroid-specific promoter of the human GATA-1 gene directs the high expression of a reporter gene in K562 cells. Multiple putative transcription factor binding sites were identified in the promoter from the -860 to the -1 base pair （bp）. For a better understanding of the transcriptional control of human GATA-1 gene expression, we tested the transcriptional activity of a series of deletions from the 5′ end of the 860-bp promoter. A region between -221 and -128 bp retains most of the transcriptional activity of the full-length promoter. Deletion of the CGCCC box at-195 bp reduced reporter gene activity to 60.4%. Further deletion of the CACCC box at -173 bp nearly abolished reporter gene expression, indicating that the CACCC box is more critical. In vitro experiments of electrophoretic mobility shifts and in vivo studies using chromatin immuno-precipitation （CHIP） assays show that the Sp1/Sp3 proteins bind the CACCC site in the nuclei of K562 cells. Coincidently, hyperacetylation of histones in the GATA-1 erythroid promoter was also shown by ChIP assay. Co-transfection of Spl expression plasmids and plasmids with a wild-type promoter showed enhanced reporter gene activity in a dose-dependent manner. The combined data demonstrate that Sp1/Sp3, but not EKLF, is involved in the activation of the GATA-1 erythroid promoter, and that histones H3 and H4 are highly acetylated in this promoter region for an actively transcribed GATA-1 gene in K562 cells in which EKLF is barely detectable.
文摘An Amh promoter driving expression of a reporter gene (d2EGFP) has been used to analyze the role of two specific promoter transcription factor binding elements. In addition a downstream (3’) enhancer (DE) was also investigated. The transcription factors GATA-1 and GATA-4 had opposite effects, the former being incremental and the latter decremental. The quantitative balance between these two factors may provide a degree of control over the level of gene expression.
基金Supported by a grant from National Scaling Height Program, China (No. 95-zhuan-10)
文摘Objective： The aim of the study was to investigate the expression pattern of hematopoietic transcription factor GATA-1, -2 and -3 genes in leukemic bone marrow （BM） micreenvironment [including bone marrow stremal cells （BMSCs） and BM hematopoietic cells]. Methods： Mononuclear cells were isolated from BM of patients with acute myeloid leukemia （AML）, chronic myelogenous leukemia （CML）, or acute lymphoblasUc leukemia （ALL）. Adherent cells （BMSCs） and nonadherent ceils （BM hematopoietic cells） were collected after long-term culture in vitro. The semi-quantitative expression levels of GATA genes in the BMSCs or BM hematopoietic cells from patients with leukemia were analyzed by using RT-PCR-ELISA and com- pared with normal controls. Results： The expression level of GATA-1 gene in the BMSCs from CML group was significantly lower than that of the normal controls. The expression level of GATA-3 gene in the BMSCs from ALL was higher than that of the normal controls, but that from CML was lower than the normal controls. Dominant expression of GATA-3 gene was found in the normal BM hematopoietic cells. The dominant expression of GATA-2 gene was found in the normal BMSCs and the BMSCs from CML, whereas the dominant expression of GATA-3 gene was detected in the BMSCs from AML. Conclusion： GATA-1, -2 and -3 genes might play a role in hematopoiesis regulation in leukemia, and the changes of expression pattern of GATA genes might influence the hematopoiesis in BM microenvironment and relate to the pathogenesis and development of leukemia.
