Circadian control of the cellular response to beta-ecdysone in Drosophila lebanonensis. I. Experimental puff induction and its relation to puparium formation.

Abstract

Drosophila lebanonensis displays a strict circadian rhythm with regard to the puparium formation and the occurrence of ecdysone-specific puffs in the salivary gland chromosomes. In normal development these puffs occur 3–4 hours before puparium formation. Injection of β-ecdysone at periods before ecdysone puffs are present, induces in all instances their appearance within 30 minutes, irrespective of the phase of the circadian oscillation at the time of injection. In spite of the appearance of the hormone specific puffs following β-ecdysone injection, puparium formation did not occur 3–4 hours after the puffs became active. Depending upon the time of injection within the circadian cycle, puparium formation occurred 5–6 hours after injection (when injection was performed close to a “gate” period), or occurred during the next “gate” of the circadian oscillation.