Essential transcription regulator during early development. Coactivates transcription of some euchromatin genes and repress transcription in of euchromatin genes translocated to heterochromatin. On polytene chromosomes, it mainly localizes to transcriptionally active euchromatin sites but also localizes to heterochromatic regions such as the chromocenter and the chromosome 4. Cytoplasmic in nursing cells and growing oocytes. Widely expressed. Highly expressed in ovary. Expressed in nursing cells and growing oocytes at all stages of development and accumulates in mature oocytes. Expressed in the nuclei of syncytium blastoderm of early embryos and in the nuclei of different tissues of late embryos, larvae, and adults. Expressed throughout all stages of development. Expressed at higher level in adult females. The PHD fingers mediate the transcription repression in heterochromatin. The SAY domain is essential for fly viability and transcription activation. Belongs to the SAYP family. Truncated N-terminus.