Fig. 3.

Dll is expressed in the bristle cells, but not in the rest of the abdominal appendage. a During embryogenesis, Dll expression occurs in the thoracic legs (L1, L2, and L3) of T. biloba. b During embryogenesis, there is no Dll expression in the abdomen, including the ventral side of abdominal segment four (A4), where the appendages will eventually develop. c At 48 h APF, Dll is expressed in the developing bristle cells, which has been observed in Drosophila (Campbell and Tomlinson 1998), but not in the rest of the abdominal appendage. This pattern continues at 72 h APF (d) with strong Dll expression in the bristle cells but none in the surrounding appendage. A close-up of the bristle shaft cells (e) demonstrates that the expression of Dll is localized to bristle cells only, and is not in the appendage tissue surrounding the bristles. The Dll expression in the bristle cells is nuclear (bcn). f DAPI staining of the appendage at the same stage as e shows that the bristle cell nucleus (bcn) is a donut shape. Dll expression in the bristles of the appendage is the same pattern of expression seen in other bristles cells of the abdomen, such as on the fifth abdominal segment (g). h A summary of Dll expression in the abdominal appendage