Transcription factor. Activates the epsilon- and gamma-globin gene promoters and, to a much lower degree, the beta-globin gene and represses promoters containing SP1-like binding sites inhibiting cell growth (By similarity). Represses transcription of SMAD7 which enhances TGF-beta signaling. Induces apoptosis. Interacts with SIN3A. By TGF-beta. Expressed in a circadian manner in the kidney and epididymal fat tissue. Mice breed normally and are fertile. Hematopoiesis at all stages of development is normal and there is no effect on globin gene expression or longevity. Belongs to the Sp1 C2H2-type zinc-finger protein family.