Transcriptional repressor which functions as a downstream effector of Notch signaling. Expressed following gastrulation. At the 1-somite stage, expressed in the paraxial mesoderm. Subsequently expressed in the telencephalon, the otic vesicles, the somites and the anterior presomitic mesoderm. Expression in the developing embryo is induced by activation of the Notch signaling pathway. Belongs to the HEY family.