The axon-guidance roundabout gene affects the communication in the circadian network

JIMENA BERNI; ESTEBAN BECKWITH; EZEQUIEL ARANOVICH; M. FERNANDA CERIANI

Sandestin, Florida, Estados Unidos

Congreso; XX Meeting of the Society for Biological Rhythms; 2008

Society for Biological Rhythms

Great efforts have been directed to the dissection of the cell-autonomous circadian oscillator in Drosophila.However, less information is available regarding how this oscillator controls rhythmic rest-activitycycles. We have identified a viable allele of roundabout, robohy, where the period of locomotor activity isshortened. From its role in axon pathfinding we anticipated developmental defects in circadian structures;however robohy produced minor defects in the architecture of the circuits essential for rhythmic behavior.The observation that ROBO is detected in the circadian network, coupled to its effect on rhythmicity whendownregulated specifically within the PDF circuit in the adult strengthened the possibility of a novel rolefor ROBO at this postdevelopmental stage. Genetic interactions between pdf01 and robohy suggest thatROBO could alter the communication within different clusters of the circadian network, thus impingingon two basic properties, periodicity and / or rhythmicity. In particular, introducing a copy of robohy intopdf01 gave rise to over 80% rhythmic individuals and also rescued the morning anticipation, suggestingthat PDF-independent factors could modulate this circadian behavior. Early translocation of PERIOD tothe nucleus in robohy pacemaker cells were first detected in adult flies indicating that robohy could onlyaffect the molecular oscillations when the adult circadian network is functional. We propose that distortedneuronal activity caused by defective synaptic contacts in any component of the circadian network could inturn impinge upon the molecular oscillations in the small LNvs.