More dorsally, active Dpp signaling represses "rhomboid" thus confining it to the lateral blastoderm nuclei. First 13 nuclear divisions take place forming a syncytial blastoderm consisting of approximately 6000 nuclei. These patterns of expression are established within the syncytial blastoderm. Early on, 256 nuclei migrate to the perimeter of the egg, creating the syncytial blastoderm. In chicken eggs, the blastoderm represents a flat disc after embryonic fertilization. At the early blastoderm stage, Dpp signaling is uniform and low along the dorsal side. These actomyosin rings invaginate to separate all nuclei for one another in the syncytial blastoderm. Wingless acts on Engrailed-expressing cells to stabilize Engrailed expression after the cellular blastoderm forms. By implanting a fragment of quail Koller's sickle into a chicken blastoderm, Drs. At the edge of the blastoderm is the site of active migration by most cells. Interior cells of the blastoderm move towards the outer cells, thus "intercalating" with each other.