[SAYP--a novel regulator of metazoan development].

SAYP is a dual-function transcriptional coactivator of RNA polymerase II. It is a metazoan-specific factor involved in different signaling pathways that control normal development. In Drosophila, SAYP is present in the organism from the early stages of development and participates in cell cycle synchronization at the blastoderm stage. SAYP is abundant in many embryonic cells and in imaginal discs of larvae and is crucial for oogenesis in adults. At the molecular level, SAYP serves as a basis for assembling the BTFly nuclear supercomplex consising of the Brahma and TFIID coactivators. We suppose that BTFly and other similar nuclear supercomplexes play an important role in ontogenesis.