Univ.-Prof. Dr. Mario De Bonio
Animals adopt different global states in responses to threats or opportunities. By using C. elegans to deconstruct such switches in animal state in molecular detail, at single neuron resolution, the de Bono group seeks to discover mechanisms that underpin fundamental properties of neurons and circuits. At a molecular level, recent discoveries include: finding that interleukin 17 acts as a neuromodulator; finding that two fold changes in calmodulin levels have marked effects on behavior and neural properties, and that a general and conserved mechanism regulates calmodulin levels in neurons; identifying a protein complex in the endoplasmic reticulum that performs co-translational quality control of nascent GPCRs, ion channels, and transporters and whose absence alters levels of these proteins; and finding a new arm of the insulin signalling pathway that regulates ageing. At a circuitry level we are unravelling how a hub-and-spoke circuit connected by chemical and electrical synapses integrates information across a range of sensory modalities to regulate behavior.
Focal points of interest
A feature of the global switches in an animal’s state we are studying is cross-modal inhibition of sensory pathways. For example, animals kept at 21% O2, a noxious signal for C. elegans, inhibit their responses to carbon dioxide and pheromones. The inhibitory pathways mediating this reprogramming are not clear, and elucidating them is one focus. C. elegans has 26 GABAergic neurons that define at least 6 neuron types. These neurons regulate locomotion, foraging, and sleep, behaviors we have worked on over the years.
Technical proficiency and instrumentation
The lab has state-of-the-art expertise in using C. elegans. Approaches we use include genetics, genomics, biochemistry, imaging neural activity of freely behaving animals, and automated behavior analysis from video. We use CRISPR to make knockins or knockouts, auxin-induced degrons to control the stability of tagged proteins in space and time, FACS sorting of dissociated animals to profile gene expression in single neurons, TRAP seq to profile translation in specific neurons, and whole genome sequencing to identify mutations obtained in forward genetic screens. We have promoters that allow us to drive expression specifically in single pairs of neurons. We have developed and optimized proximity labelling protocols to allow us to perform in vivo biochemistry in single identified neurons. We use tissue culture and mouse transgenics to extend discoveries made in C. elegans to mammals.
Aspirations for the next 5 years
We have several goals. One is to establish functions for conserved, metazoan-specific proteins that are expressed selectively in the nervous system but about which almost nothing is known. We seek to elucidate the functions of these proteins at biochemical, cell biological and physiological levels. A second goal is to biochemically characterize specific synapses in single identified neurons. One goal here is to highlight the molecular architecture of gap junctions, and to identify molecules and mechanisms that regulate their cell biology and function. A third goal is to elucidate molecular mechanisms that sustain tonic circuit activity over hours, and that allow gradual reprogramming of circuit properties to alter animal behavior and physiology.
References
- Neuronal calmodulin levels are controlled by CAMTA transcription factors. Vuong-Brender TT, Flynn S, Vallis Y, de Bono M. 2021 Elife 10, e68238.
- Natural variation in a dendritic scaffold protein remodels experience-dependent plasticity by altering neuropeptide expression. Beets I, Zhang G, Fenk LA, Chen C, Nelson GM, Félix MA, de Bono M. Neuron 2020 105, 106–121.
- Depletion of endogenously biotinylated carboxylases enhances the sensitivity of TurboID-mediated proximity labeling in Caenorhabditis elegans. Artan, M, Hartl M, Chen W, de Bono M. J Biol Chem 2022 298, 10343.
