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.