Temperature entrainment of the molecular circadian clock circuits in Drosophila

Circadian clocks generate and organize daily rhythms in animal physiology and behaviour. While their periodicity is temperature-compensated, circadian clocks in both poikolithermic and homeothermic organisms do synchronize to temperature cycles. The conserved core circadian regulator PERIOD (PER) is key to both temperature compensation and temperature entrainment. The PI recently uncovered strong temperature-driven transcriptional regulation of the per gene in the representative circadian model organism Drosophila melanogaster. Given the importance of the daily PER expression profile in the circadian oscillator as well as the proposed role of mammalian Per2 in temperature entrainment the newly uncovered temperature-driven per transcription is hypothesized to contribute to temperature-dependent regulation of daily time keeping. It is the aim of this project to provide insight in the mechanisms underlying circadian temperature entrainment and compensation by elucidating the role of temperature-driven per transcription. To this aim the responsible cis-regulatory elements will be genetically mapped in the per gene and their ability to confer temperature-driven regulation to the native per gene as well as reporter constructs will be determined. In addition, transcription factors involved in this process will be identified by candidate gene tests and systematic genetic screens in flies as well as a comprehensive set of Yeast 1-Hybrid assays. Molecular and behavioural time keeping, temperature entrainment, and temperature compensation phenotypes resulting from the disruption of the cis and trans-acting mediators of temperature-driven per transcription will be determined by gene expression and locomotor activity assays. Ultimately, this project is expected to provide new insights in the mechanisms underlying temperature-dependent regulation of molecular and behavioural circadian rhythms in animals and humans involving the conserved core clock component PER.