ANALYSIS OF PERIOD MESSENGER-RNA CYCLING IN DROSOPHILA HEAD AND BODY-TISSUES INDICATES THAT BODY OSCILLATORS BEHAVE DIFFERENTLY FROM HEAD OSCILLATORS

The period (per) gene is thought to be part of the Drosophila circadia n pacemaker. The circadian fluctuations in per RNA and protein that co nstitute the per feedback loop appear to be required for pacemaker fun ction, and have been measured in head neuronal tissues that are necess ary for locomotor activity and eclosion rhythms. The per gene is also expressed in a number of neuronal and nonneuronal body tissues for whi ch no known circadian phenomena have been described. To determine whet her per might affect some circadian function in these body tissues, pe r RNA cycling was examined. These studies show that per RNA cycles in the same phase and amplitude in head and body tissues during light-dar k cycles. One exception to this is the lack of per RNA cycling in the ovary, which also appears to be the only tissue in which PER protein i s primarily cytoplasmic. In constant darkness, however, the amplitude of per RNA cycling dampens much more quickly in bodies than in heads. Taken together, these results indicate that circadian oscillators are present in head and body tissues in which PER protein is nuclear and t hat these oscillators behave differently.