Construct: zen promoter region deleted between (approximate) coordinates -0.350kb and -0.042kb.
The 1.6 kb zen upstream region deleted between coordinates -300 and -42 is sufficient to drive dorsal EcollacZ expression in the precellular embryo. After cellularization, EcollacZ expression in the transformants is abnormal, and does not become further refined. This region is necessary for the refinement of the zen pattern of expression, and its function is separable from elements controlling dorsal expression.