At stage 11, the EcollacZ^SCE enhancer is active in seven sets of cells in the most dorsal part of the mesoderm. EcollacZ^SCE is also active in additional cells slightly ventral to this, precursors of dorsal somatic muscles. There is also enhancer activity in cells closely apposed to the ventral ectoderm, which are likely to be a subset of the neuroblasts previously shown to express svp. During stage 12, enhancer activity intensifies in the dorsal mesoderm, and is still overlapping with tin. At stage 14, EcollacZ^SCE activity is strong in both the svp-positive cells of the dorsal vessel and in the dorsal somatic muscles. At stage 16, EcollacZ^SCE can be seen in all seven clusters of svp-positive cells, and small amounts of residual signal can be detected in the svp-positive pericardial cells.