title: GATA-1 mediates auto-regulation of Gfi-1B transcription in K562 cells.
abstract: Gfi-1B (growth factor independence-1B) gene is an erythroid-specific transcription factor, whose expression plays an essential role in erythropoiesis. Our laboratory has previously defined the human Gfi-1B promoter region and shown that GATA-1 mediates erythroid-specific Gfi-1B transcription. By further investigating the regulation of the Gfi-1B promoter, here we report that (i) Gfi-1B transcription is negatively regulated by its own gene product, (ii) GATA-1, instead of Gfi-1B, binds directly to the Gfi-1-like sites in the Gfi-1B promoter and (iii) Gfi-1B suppresses GATA-1-mediated stimulation of Gfi-1B promoter through their protein interaction. These results not only demonstrate that interaction of GATA-1 and Gfi-1B participates in a feedback regulatory pathway in controlling the expression of the Gfi-1B gene, but also provide the first evidence that Gfi-1B can exert its repression function by acting on GATA-1-mediated transcription without direct binding to the Gfi-1 site of the target genes. Based on these data, we propose that this negative auto-regulatory feedback loop is important in restricting the expression level of Gfi-1B, thus optimizing its function in erythroid cells.
authors.affiliation: Institute of Biochemistry and Molecular Biology, College of Medicine, National Taiwan University, No. 1 Jen Ai Road 1st Section, Taipei, Taiwan, ROC.
authors.forename: Duen-Yi
authors.initials: DY
authors.lastname: Huang
authors.forename: Yuan-Yeh
authors.initials: YY
authors.lastname: Kuo
authors.forename: Zee-Fen
authors.initials: ZF
authors.lastname: Chang
mesh_terms: D001483:Base Sequence; D001665:Binding Sites; D004268:DNA-Binding Proteins / Q000037:antagonists & inhibitors / Q000502:physiology*; D015536:Down-Regulation; D050981:Erythroid-Specific DNA-Binding Factors; D050982:GATA1 Transcription Factor; D005786:Gene Expression Regulation; D006706:Homeostasis; D006801:Humans; D020014:K562 Cells; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D017434:Protein Structure, Tertiary; D011518:Proto-Oncogene Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D012097:Repressor Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D014157:Transcription Factors / Q000037:antagonists & inhibitors / Q000502:physiology*; D014158:Transcription, Genetic; D015533:Transcriptional Activation
chemical_list: D004268:DNA-Binding Proteins; D050981:Erythroid-Specific DNA-Binding Factors; D050982:GATA1 Transcription Factor; C494688:GATA1 protein, human; C111977:GFI1B protein, human; D011518:Proto-Oncogene Proteins; D012097:Repressor Proteins; D014157:Transcription Factors