Liliane Abuin | Search bioRxiv

bioRxiv2020

Targeted molecular profiling of rare cell populations identifies olfactory sensory neuron fate and wiring determinants

Determining the molecular properties of neurons is essential to understand their development, function and evolution. We used Targeted DamID (TaDa) to characterize RNA polymerase II occupancy and chromatin accessibility in selected Ionotropic Receptor (IR)-expressing sensory neurons in the Drosophila antenna. Although individual populations represent a minute fraction of cells, TaDa is sufficiently sensitive and specific to identify the expected receptor genes. Unique Ir expression is not linked to substantial differences in chromatin accessibility, but rather to distinct transcription factor profiles. Heterogeneously-expressed genes across populations are enriched for neurodevelopmental factors, and we identify functions for the POU-domain protein Pdm3 as a genetic switch of Ir neuron fate, and the atypical cadherin Flamingo in segregation of neurons into discrete glomeruli. Together this study reveals the effectiveness of TaDa in profiling rare neural populations, identifies new roles for a transcription factor and a neuronal guidance molecule, and provides valuable datasets for future exploration.Competing Interest StatementThe authors have declared no competing interest.View Full Text

neuroscience↗

bioRxiv2016

Distinct combinations of variant ionotropic glutamate receptors mediate thermosensation and hygrosensation in Drosophila

Ionotropic Receptors (IRs) are a large subfamily of variant ionotropic glutamate receptors present across Protostomia. While these receptors are most extensively studied for their roles in chemosensory detection in insects, recent work has implicated two family members, IR21a and IR25a, in thermosensation in Drosophila. Here we characterize one of the most deeply conserved receptors, IR93a, and show that it is co-expressed and functions with IR21a and IR25a to mediate physiological and behavioral responses to cool temperatures. IR93a is also co-expressed with IR25a and a distinct receptor, IR40a, in a discrete population of sensory neurons in the sacculus, a multi-chambered pocket within the antenna. We demonstrate that this combination of receptors is important for neuronal responses to dry air and behavioral discrimination of humidity differences. Our results identify IR93a as a common component of molecularly and cellularly distinct IR pathways underlying thermosensation and hygrosensation in insects.

Neuroscience↗