Transcription repressor essential for hematopoiesis. Functions in a cell-context and development-specific manner. Binds to 5'-TAAATCAC[AT]GCA-3' in the promoter region of a large number of genes. Component of several complexes, including the EHMT2-GFI1-HDAC1, AJUBA-GFI1-HDAC1 and RCOR-GFI-KDM1A-HDAC complexes, that suppress, via histone deacetylase (HDAC) recruitment, a number of genes implicated in multilineage blood cell development. Regulates neutrophil differentiation, promotes proliferation of lymphoid cells, and is required for granulocyte development. Mediates, together with U2AF1L4, the alternative splicing of CD45 and controls T-cell receptor signaling. Regulates the endotoxin-mediated Toll-like receptor (TLR) inflammatory response by antagonizing RELA. Cooperates with CBFA2T2 to regulate ITGB1-dependent neurite growth. Controls cell-cycle progression by repressing CDKNIA/p21 transcription in response to TGFB1 via recruitment of GFI1 by ZBTB17 to the CDKNIA/p21 and CDKNIB promoters. Required for the maintenance of inner ear hair cells. Interacts with U2AF1L4. Component of RCOR-GFI-KDM1A-HDAC complexes. Interacts directly with RCOR1, KDM1A and HDAC2 (By similarity). Also interacts with HDAC1. Interacts (via the zinc-finger domain) with ARIH2; the interaction prevents GFI1 ubiquitination and proteasomal degradation. Interacts with PIAS3; the interaction relieves the inhibitory effect of PIAS3 on STAT3-mediated transcriptional activity. Forms a complex with EHMT2 and HDAC1 to promote 'Lys-9' dimethylation of H3 (H3K9Me2) and repress expression of target genes. Interacts directly with EHMT2. Component of the GFI1-AJUBA-HDAC1 repressor complex. Interacts directly with AJUBA (via ITS LIM domains); the interaction results in the HDAC-dependent corepression of a subset of GFI1 target genes and, occurs independently of the SNAG domain. Interacts with SPI1; the interaction inhibits SPI1 transcriptional activity and represses SPI1-regulated macrophage-specific genes required for proper granulocyte development. Interacts with RUNX1T1; the interaction represses HDAC-mediated transcriptional activity. Interacts with RELA; the interaction occurs on liposaccharide (LPS) stimulation and controls RELA DNA binding activity and regulates endotoxin-mediated TOLL-like receptor inflammatory response. Interacts (via the C-terminal zinc fingers) with ZBTB17; the interaction results in the recruitment of GFI1 to the CDKN1A/p21 and CDKN1B promoters and repression of transcription. Colocalizes with PIAS3 and RUNX1T1 in nuclear dots. Down-regulated by TGFB1. Zinc fingers 3, 4 and 5 are required for DNA-binding and for interaction with SPI1. The SNAG domain of GFIs is required for nuclear location and for interaction with some corepressors. Ubiquitinated. Ubiquitination and degradation by the proteasome is inhibited by the ubiquitin ligase, ARIH2. The disease is caused by variants affecting the gene represented in this entry. The disease is caused by variants affecting the gene represented in this entry. GFI1 mutation db