Transcription regulator that modulates expression mediated by transcription factors of the GATA family such as pnr and srp. Represses transcription of proneural achaete-scute complex (AS-C), which is usually activated by pnr. Involved in cardiogenesis, blood, and eye development. During hematopoiesis, it is required to restrict the number of crystal cells, probably via its interaction with the isoform SrpNC of srp. Negatively regulates expression of sr. Probably acts by interacting with the GATA-type zinc finger of proteins such as pnr and srp, possibly antagonizing the interaction between the GATA-type zinc finger and some cofactor. Interacts with pnr, although weak this interaction is essential. Interacts with the isoform SrpNC of srp. Interacts with CtBP corepressor. First expressed in stage 5 at high levels in the primordium of the amnioserosa. Also expressed in germ band extending embryos in cells of the developing anterior and posterior midgut and in hemocyte precursors present in the cephalic mesoderm. In embryonic stage 8, it is expressed in blood cell precursors. By stage 10, it is expressed in hemocyte precursors that have spread throughout the lateral and ventral head mesoderm. By stage 11, it is expressed in the dorsal ectoderm and in precursor cells of the hemocytes and fat body. As embryogenesis proceeds, it is also expressed in stage 13 plasmatocytes migrating throughout the head mesoderm and down the ventral midline. By late embryogenesis, expression strongly decreases but remains in the dorsal ectoderm during dorsal closure, in cells within, or associated with, the central nervous system, and in plasmatocytes circulating throughout the embryonic hemolymph. During larval development, it is expressed in primary and secondary lobes of lymph glands. Expressed in the dorsal part of the thoracic imaginal disk. The CCHC FOG-type zinc fingers 1, 4 and 5 directly bind to GATA-type zinc fingers. The Tyr residue adjacent to the last Cys of the CCHC FOG-type zinc finger is essential for the interaction with GATA-type zinc fingers. Belongs to the FOG (Friend of GATA) family.