Plays a role as a transcriptional repressor during development. May play a role in the control of cell survival. Interacts with HDAC1 and ATN1. Interaction with ATN1 is improved when the poly-Gln region of ATN1 is extended. Interacts with FAT1 (By similarity). Localized in nuclear bodies of variables size. Colocalized with PML and BAX in nuclear PODs (By similarity). At 8.25 dpc expression is strongly elevated in the anterior midline. At 8.5 dpc expression is elevated throughout the anteroposterior extent of the notochord and is down-regulated in the heart. At 8.75 dpc expression is increased in the ventral brain. At 9.5 dpc strong expression appears besides the notochord including the apical ectodermal ridge (AER), the isthmus and the ventral diencephalon. At 10.5 dpc expression increases in the notochord, the AER and spinal and brain neurons. The interaction with ATN1 is mediated by the coiled domain. Mice embryos exhibit a variety of patterning defects that first appear at 8.0 dpc. Defects include a specific failure in ventralization of the anterior neural plate, loss of heart looping and irregular partitioning of somites. In mutant embryos, Shh expression fails to initiate along the anterior midline at 8.0 dpc, and Fgf8 is delocalized from the anterior neural ridge at 8.5 dpc.