Cell autonomous and non-autonomous mechanisms underlying axonal terminal remodeling of pacemaker neurons in Drosophila

DUHART, JM; DUHART, JM; HERRERO, A; HERRERO, A; CERIANI, MF; CERIANI, MF

Congreso; XXXII Congreso de la Sociedad Argentina de Neurociencias; 2017

A number of years ago we reported that pigment dispersing factor (PDF) neurons, which are essential in the control of rest-activity cycles in Drosophila, undergo circadian remodeling of their axonal projections. We then proposed that such adult-specific remodeling could provide a means of transmitting time-of-day information complementary to differential neurotransmitter release (i.e., PDF). In terms of clock- dependent mechanisms, several neuronal types undergoing circadian remodeling hinted to a differential effect of clock genes;suggesting these genes could be playing additional roles to those ascribed to core clock function. To shed light onto this possibility we altered clock gene levels through RNAimediated downregulation and expression of dominant negative forms exclusively in the adult. These experiments confirmed that a cell-autonomous circadian clock is sufficient to drive the remodeling process independently of the clock protein affected. Interestingly, affecting the positive and negative elements of the feedback loop associated to distinctiveconfigurations. Given the extent of the structural changes involved, glia would be expected to play a role to balance changes in neuronal volume and structure. Thus, we explored the contribution of glia to the remodeling of PDF neurons through disruption of their internal clock. Our results reveal the complexity of the mechanisms underlying structural remodeling taking place daily in taking place daily in the adult brain.