Biology subjects

Bervoets, S.

Publications and source records attributed to Bervoets, S..

3 recordsLinked to original sources

bioRxiv2026

Arc capsid signaling between serotonergic and dopaminergic neurons sets sleep depth in Drosophila

Arc genes evolved from Ty3 retrotransposons and encode proteins that self-assemble into virus-like capsids that package and transfer RNA between cells. This capsid-forming property may mediate a form of intercellular signaling distinct from classical synaptic transmission, but whether it operates within a defined neuronal system to control an ongoing behavior remains unclear. Here we show that Arc-dependent capsid signaling links serotonergic and PAM neurons to set sleep depth in Drosophila melanogaster. Loss of dArc genes deepened and consolidated sleep, increasing both sleep depth and the arousal threshold to mechanical stimulation, while leaving the diurnal sleep pattern intact. dArc1 was required in serotonergic neurons and, to a lesser extent, in PAM neurons, and both the loss-of-function phenotype and its rescue depended on capsid formation. Knocking down dArc1 in Sas-expressing cells, or Ptp10D in PAM neurons, reproduced the deeper, more consolidated sleep of dArc-/-flies, implicating the Sas-Ptp10D machinery in this signaling. These results identify Arc-dependent capsid signaling as a mechanism that links two modulatory neuronal populations to regulate an ongoing homeostatic behavior.

neuroscience↗

bioRxiv2024

dArc1 controls sugar reward valuation in Drosophila melanogaster

The Arc genes -- which include Drosophila Arc1 and Arc2 (dArc) -- evolved from Ty3 retrotransposons and encode proteins that form virus-like capsids. These capsids enable a novel form of intercellular communication by transferring RNAs between cells. However, the specific neuronal circuits and brain processes Arc intercellular signaling regulates remain unknown. Here, we show that loss of both dArc genes in Drosophila melanogaster enhances associative learning in an appetitive conditioning paradigm, where flies associate an odor with sugar rewards. This increased learning performance arises from an increased valuation of sugar rewards: unlike wild-type flies, dArc-/- flies form abnormally strong associations even when the sugar reward is small or has no caloric value. We found that the {gamma}5-dopaminergic neurons of the protocerebral anterior medial (PAM) cluster, which encode the positive valence of sugar rewards, show heightened activity in response to sucrose in dArc-/- flies. We further show that the learning phenotype of dArc-/- flies depends on the formation of capsids, underscoring a direct role for capsid-mediated Arc signaling in sugar valuation. Our findings establish dArc genes as critical regulators of reward valuation in D. melanogaster, acting through a non-cell autonomous mechanism that relies on capsid-mediated communication between cells.

neuroscience↗

bioRxiv2023

Evolution of connectivity architecture in the Drosophila mushroom body

Brain evolution has primarily been studied at the macroscopic level by comparing the relative size of homologous brain centers between species. How neuronal circuits change at the cellular level over evolutionary time remains largely unanswered. Here, using a phylogenetically informed framework, we compare the olfactory circuits of three closely related Drosophila species that differ radically in their chemical ecology: the generalists Drosophila melanogaster and Drosophila simulans that feed on fermenting fruit, and Drosophila sechellia that specializes on ripe noni fruit. We examine a central part of the olfactory circuit that has not yet been investigated in these species -- the connections between the projection neurons of the antennal lobe and the Kenyon cells of the mushroom body, an associative brain center -- to identify species-specific connectivity patterns. We found that neurons encoding food odors -- the DC3 neurons in D. melanogaster and D. simulans and the DL2d neurons in D. sechellia -- connect more frequently with Kenyon cells, giving rise to species-specific biases in connectivity. These species-specific differences in connectivity reflect two distinct neuronal phenotypes: in the number of projection neurons or in the number of presynaptic boutons formed by individual projection neurons. Finally, behavioral analyses suggest that such increased connectivity enhances learning performance in an associative task. Our study shows how fine-grained aspects of connectivity architecture in an associative brain center can change during evolution to reflect the chemical ecology of a species.

neuroscience↗