Required during somitogenesis to regulate somite differentiation and the positioning of the presomitic mesoderm-front. Represses the expression of genes involved in somite segmentation by acting with the corepressor tle4 to down-regulate the transcriptional activity of tbx6. Also regulates retinoic acid signaling during somitogenesis and is necessary for the expression of aldh1a2/raldh2. Expressed in the presomitic mesoderm (PSM) in the anterior halves of somitomeres S-0, S-I and S-II and in the newly formed somites. Expressed from stage 12. By notch signaling. By tbx6 together with thy1 and tcf3. The ripply homology domain is required for transcriptional repression. The WRPW motif is required for binding to tle/groucho proteins and transcriptional repression. Belongs to the ripply family.