Active repression of RAR signaling is required for head formation.

@article{Koide2001ActiveRO,
  title={Active repression of RAR signaling is required for head formation.},
  author={Taro Koide and Meredith Downes and Roshantha A.S. Chandraratna and Bruce Blumberg and Kazuhiko Umesono},
  journal={Genes & development},
  year={2001},
  volume={15 16},
  pages={2111-21}
}
The retinoic acid receptors (RARs) recruit coactivator and corepressor proteins to activate or repress the transcription of target genes depending on the presence of retinoic acid (RA). Despite a detailed molecular understanding of how corepressor complexes function, there is no in vivo evidence to support a necessary function for RAR-mediated repression. Signaling through RARs is required for patterning along the anteroposterior (A-P) axis, particularly in the hindbrain and posterior, although… CONTINUE READING