Definition: Cells in certain regions of an embryo that self-regulate embryonic development. These organizers have been found in dorsal and ventral poles of GASTRULA embryos, including Spemann organizer in amphibians, and Hensen node in chicken and mouse. These organizer cells communicate with each other via a network of secreted signaling proteins, such as BONE MORPHOGENETIC PROTEINS and their antagonists (chordin and noggin).
