Beschreibung:
<jats:p>
Gradients of extracellular signaling molecules and transcription factors are used in a variety of developmental processes, including the patterning of the
<jats:italic>Drosophila</jats:italic>
embryo, the establishment of diverse neuronal cell types in the vertebrate neural tube, and the anterior–posterior patterning of vertebrate limbs. Here, we discuss how a gradient of the maternal transcription factor Dorsal produces complex patterns of gene expression across the dorsal–ventral (DV) axis of the early
<jats:italic>Drosophila</jats:italic>
embryo. The identification of 60–70 Dorsal target genes, along with the characterization of ≈35 associated regulatory DNAs, suggests that there are at least six different regulatory codes driving diverse DV expression profiles.
</jats:p>