Wild type (WT) stage 11 embryos express Dll transcript (red) encompassing encompassing a stripe of wg expression that demarcates the anterior field from the posterior field. Abd-A protein staining is shown in green. The white line marks the separation of the anterior and posterior fields of Dll expression (as determined by wg expression, data not shown). Stage 11 embryos ubiquitously expressing Drosophila UBX, Artemia UBX or Artemia UBX with Serine/Threonine to Alanine mutations in the C-terminus show varied abilities to repress Dll expression. Mutation of all Serines/Threonines within the C-terminus of Artemia UBX, Art UBX(1–7), results in strong repression of Dll. While mutation of the serine within the CK2 consensus site only, Art UBX(7), results in a level of Dll expression comparable to wild type Artemia UBX.