A highly magnified view of two tiny leg primordia (leg imaginal discs) from a fruitfly larva that have been immunostained with fluorescent antibodies to identify early-born sensory neurons (green nuclei) and cells that express AP-2 protein (red nuclei). The latter are precursor cells for joint tissue between leg segments and also provide essential survival signals for adjacent epithelial cells that are precursors of the "inter-joint" regions. In mutant flies lacking functional AP-2 protein, leg joints fail to develop and outgrowth of inter-joint regions is severely reduced.

Courtesy Pamela Mitchell

Close Window