PERIOD PROTEIN FROM THE GIANT SILKMOTH ANTHERAEA-PERNYI FUNCTIONS AS A CIRCADIAN CLOCK ELEMENT IN DROSOPHILA-MELANOGASTER

Homologs of the Drosophila clock gene per have recently bt!en cloned i n Lepidopteran and Blattarian insect species. To assess the extent to which clock mechanisms are conserved among phylogenetically distant sp ecies, we determined whether PER protein from the silkmoth Antheraea p ernyi can function in the Drosophila circadian timing system. When exp ressed in transgenic Drosophila, the silkmoth PER protein is detected in the expected neural cell types, with diu mal changes in abundance t hat are similar to those observed in wild-type fruitflies. Behavioral analysis demonstrates that the silkmoth protein can serve as a molecul ar element of the Drosophila clock system; expression of the protein s hortens circadian period in a dose-dependent manner and restores pacem aker functions to arrhythmic per(0) mutants. This comparative study al so suggests that the involvement of PER in different aspects of circad ian timing, such as period determination, strength of rhythmicity, and clock output, requires distinct molecular interactions.