In wild-type, neuroblast NB7-1 generates five U motoneurons. Overexpression of hbΔB.Scer\UAS.T:Hsim\VP16 in NB7-1 under the control of Scer\GAL4en-e16E produces an average of sixteen U neurons per hemisegment. Overexpression of hbΔB.Scer\UAS.T:Hsim\VP16 in hb15/hbP1only mutant NB7-1 under the control of Scer\GAL4en-e16E produces an average of twelve U neurons per hemisegment.