The development of adult muscles in Drosophila: ablation of identified muscle precursor cells

A small subset of mesodermal cells continues to express twist in the late embryo of Drosophila. These cells are the precursors of adult muscles. Each late twist-expressing cell begins to divide early in the second larval instar and division continues throughout the second and third instars, resulting in a small clone of twist-expressing cells at puparium formation. Treatment with a DNA-synthesis inhibitor, hydroxyurea (HU), ablates these cells if applied during S-phase of their replication cycle. We ablated ftM'sf-expressing lineages in the larva and demonstrated that this results in the absence of subsets of muscles in the adult abdomen and leg. HU treatment during this larval period has no discernible effect on the adult epidermis or innervation. We conclude that the fw/sf-expressing cells identified in the late embryo are th