Highly conserved Drosophila ananassae timeless gene functions as a clock component in Drosophila melanogaster

The behavior and physiology of Drosophila are subject to rhythms that are controlled by the circadian clock genes, period, timeless, clock and cycle, all of which are thought to participate in central pacemaker control. The molecular mechanism of rhythm in Drosophila has been studied in detail. However, rhythm and clock genes have mostly been analyzed in Drosophila melanogaster. To confirm whether the tim gene exists and works as a clock component in other Drosophila species, we cloned a tim homolog from Drosophila ananassae that shared 85.9% similarity with Drosophila melanogaster tim at the amino acid level. In addition, the PER interaction domains and NLS were highly conserved. Introduction of the D. ananassae tim homolog rescued the rhythm of the locomotor activity of about 44% of a population of D. melanogaster tim(01) flies. At the molecular level, hs-tim introduced not only TIM but PER oscillation in transgenic flies. These results indicate that the tim gene in D. ananassae functions as a component of the circadian clock in D. melanogaster.