Expression of dorsoventral-axis-patterning genes
Expression domains of specific dorsoventral-axis-patterning genes correspond to particular future tissue layers. (a) The maternally derived Dorsal protein is expressed in a gradient, with the highest concentration of Dorsal in the nuclei of ventral cells (bottom of photograph). (b) The expression of four zygotic dorsoventral-axis-patterning genes revealed by in situ hybridization to RNA. In this lateral view, the domains of the decapentaplegic (yellow), muscle segment homeobox (red), intermediate neuroblasts defective (green), and ventral neuroblasts defective (blue) genes are revealed.
[Courtesy of (a) Michael Levine and (b) David Kosman, Bill McGinnis, and Ethan Bier.]