CONICET | Buscador de Institutos y Recursos Humanos

The circadian systemallows synchronization of vital biochemical, cellular and physiologicalprocesses to cyclical environmental events in a wide array of organisms. InDrosophila the circadian clock is controlled by interlocked transcriptionalfeedback loops present in neuronal and non-neuronal tissues. In particular, theperiodic egg-laying behavior, or oviposition, is one of several physiologicalprocesses regulated in a circadian fashion. However, this rhythmic behavior ispoorly studied and many important aspects related with the role of themolecular clock remain to be elucidated. We study the molecular clockparticipation on egg-laying behavior by analyzing oviposition in control fliesas well as in per and tim null mutants, which lack afunctional clock. In contrast to controls, no rhythmic oviposition was detectedin mutant flies. Moreover, to study if oviposition is regulated by central orperipheral clocks, we downregulated per expression exclusively in the brain. Ourexperiments indicate that the central molecular clock is necessary for rhythmicoviposition, since a reduction of per levels exclusively in the brain inducesarrythmicity. To elucidate the identity of the central neurons involved on rhythmiccontrol of oviposition, we downregulated per expression on the small lateralventral neurons. Circadian oviposition was observed on mutant flies, indicatingno role of these neurons on rhythmic egg-laying behavior. As Drosophila has astrong egg-laying place preference behavior, we study the influence ofcircadian clocks on this preference. We implemented a setup to allow us trackingthe flies? position in a controlled environment. Preliminary results show thatplace preferences is markedly different between mated females and males. Furtherexperiments will be designed to dissect the role and hierarchy of differentcentral and peripheral neurons.