Ecdysteroid control of metamorphosis in the differentiating adult leg structures of Drosophila melanogaster.

摘要: During insect metamorphosis, the steroid hormone 20-hydroxyecdysone (20E) is responsible for coordinating differentiation of adult structures. Several structures Drosophila melanogaster leg, six distalmost joints, bristles, and pretarsal claws, were examined to investigate how 20E controls their development in vitro. Joints, claws dependent on between 20-22 24-26 h after puparium formation (APF). After 26-28 APF, became independent. Tissue-specific markers 20E-free cultures showed that bristle joint cells had not undergone any further morphogenetic progression. In contrast, pretarsi underwent partial differentiation. The concentration required was structure specific; tarsal joints higher concentrations (greater than 400 ng 20 E/ml) other 40 20E/ml). precursor ecdysone (E) also able induce at over 700 E/ml, but did show synergistic interactions with 20E. Lastly, leg a finite ability respond 20E; lost competence 32-34 while remaining incompetent 44-46 APF.