Regulation der Transkription im Uhr-Netzwerk von Drosophila melanogaster.
Zusammenfassung der Projektergebnisse
The aim of this project was to investigate the circadian clock on the transcriptional and neuronal level. Even though we were not yet able to establish the MS2 stem loop system for investigating clock gene transcription in individual neurons, we accomplished important steps to reach that goal: We incorporated stem-loops in the UTR of core clock genes and are in the process of reducing signal-to-noise issues. However, a newly developed FISH protocol from the Singer lab allowed us to investigate clock gene transcription in individual neurons in the brain. By manipulating neuronal properties we show that tim transcription is reduced in silenced neurons, suggesting neuronal firing and/or neuronal communication is necessary for proper clock gene regulation. We further focused on neuronal interactions and discovered several key findings during the period of this funding. We found that cholinergic input from a specific visual organ, called the HB-eyelet, activates key circadian neurons and thereby alters the fly’s adaptation to high light intensity. Another feature of summer days is the change of daylength. In a collaborative effort we identified a new “circadian” neuropeptide called Allatostatin C which is expressed in a subset of dorsal and lateral clock neurons. Knockdown of this peptide does not affect the behavior under equinox conditions, but significantly delays the E peak under long summer days by inhibiting a single LNd neuron. We further investigated the effect of PDF under the same conditions. We discovered a new pathway of light information integration: Light from a specific photoreceptor cell activates the lLNvs, which release PDF. By using expansion microscopy as well as cell-specific CRISPR/Cas9 knockout strategies, we show that PDF is communicating with the cells important for evening activity and thereby alter the behavior of the fly. Given the importance of G-protein coupled receptors for circadian entrainment and other functions in the brain, we are developing a “guide library” which will allow us to investigate neuronal communication within and beyond the clock network.
Projektbezogene Publikationen (Auswahl)
-
(2019) A distinct visual pathway mediates high light intensity adaptation of the circadian clock in. J Neurosci
Schlichting, M.; Menegazzi, P.; Rosbash, M. & Helfrich-Förster, C.
-
(2019) Allatostatin-C/AstC-R2 Is a Novel Pathway to Modulate the Circadian Activity Pattern in Drosophila. Curr Biol 29:13–22.e3
Díaz, Madelen M.; Schlichting, Matthias; Abruzzi, Katharine C.; Long, Xi & Rosbash, Michael
-
(2019) Light-mediated circuit switching in the Drosophila neuronal clock network
Schlichting, M.; Weidner, P.; Diaz, M.; Menegazzi, P.; Dalla-Benetta, E.; Helfrich-Förster, C. & Rosbash, M.
