title: Involvement of Sp1/Sp3 in the activation of the GATA-1 erythroid promoter in K562 cells.
abstract: 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 Sp1 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.
authors.affiliation: Laboratory of Molecular Cell Biology, Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Graduate School of the Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200031, China.
authors.forename: Chun Hui
authors.initials: CH
authors.lastname: Hou
authors.forename: Jian
authors.initials: J
authors.lastname: Huang
authors.forename: Qi Ye
authors.initials: QY
authors.lastname: He
authors.forename: Cai Ning
authors.initials: CN
authors.lastname: Zhang
authors.forename: Xue Jun
authors.initials: XJ
authors.lastname: Zhang
authors.forename: Ruo Lan
authors.initials: RL
authors.lastname: Qian
mesh_terms: D000107:Acetylation; D001483:Base Sequence / Q000235:genetics; D050982:GATA1 Transcription Factor / Q000096:biosynthesis* / Q000235:genetics; D005786:Gene Expression Regulation / Q000502:physiology*; D006657:Histones / Q000235:genetics / Q000378:metabolism; D006801:Humans; D020014:K562 Cells; D051741:Kruppel-Like Transcription Factors / Q000235:genetics / Q000378:metabolism; D020218:Response Elements / Q000502:physiology*; D017384:Sequence Deletion; D016329:Sp1 Transcription Factor / Q000235:genetics / Q000378:metabolism*; D051705:Sp3 Transcription Factor / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic / Q000502:physiology*
chemical_list: D050982:GATA1 Transcription Factor; C494688:GATA1 protein, human; D006657:Histones; D051741:Kruppel-Like Transcription Factors; C497121:SP3 protein, human; D016329:Sp1 Transcription Factor; C080774:erythroid Kruppel-like factor; D051705:Sp3 Transcription Factor