Evolution of chemosensory tissues and cells across ecologically diverse Drosophilids.

Chemosensory tissues exhibit significant between-species variability, yet the evolution of gene expression and cell types underlying this diversity remain poorly understood. To address these questions, we conducted transcriptomic analyses of five chemosensory tissues from six Drosophila species and integrated the findings with single-cell datasets. While stabilizing selection predominantly shapes chemosensory transcriptomes, thousands of genes in each tissue have evolved expression differences.

Publisher Correction: An expression atlas of variant ionotropic glutamate receptors identifies a molecular basis of carbonation sensing.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

An expression atlas of variant ionotropic glutamate receptors identifies a molecular basis of carbonation sensing.

Through analysis of the Drosophila ionotropic receptors (IRs), a family of variant ionotropic glutamate receptors, we reveal that most IRs are expressed in peripheral neuron populations in diverse gustatory organs in larvae and adults. We characterise IR56d, which defines two anatomically-distinct neuron classes in the proboscis: one responds to carbonated solutions and fatty acids while the other represents a subset of sugar- and fatty acid-sensing cells. Mutational analysis indicates that IR56d, together with the broadly-expressed co-receptors IR25a and IR76b, is essential for physiological responses to carbonation and fatty acids, but not sugars.

Multisensory neural integration of chemical and mechanical signals.

Chemosensation and mechanosensation cover an enormous spectrum of processes by which animals use information from the environment to adapt their behavior. For pragmatic reasons, these sensory modalities are commonly investigated independently. Recent advances, however, have revealed numerous situations in which they function together to control animals' actions.

Neuregulin 3 Mediates Cortical Plate Invasion and Laminar Allocation of GABAergic Interneurons.

Neural circuits in the cerebral cortex consist of excitatory pyramidal cells and inhibitory interneurons. These two main classes of cortical neurons follow largely different genetic programs, yet they assemble into highly specialized circuits during development following a very precise choreography. Previous studies have shown that signals produced by pyramidal cells influence the migration of cortical interneurons, but the molecular nature of these factors has remained elusive.

A mechanosensory receptor required for food texture detection in Drosophila.

Textural properties provide information on the ingestibility, digestibility and state of ripeness or decay of sources of nutrition. Compared with our understanding of the chemosensory assessment of food, little is known about the mechanisms of texture detection. Here we show that Drosophila melanogaster can discriminate food texture, avoiding substrates that are either too hard or too soft.

Cxcl12/Cxcr4 signaling controls the migration and process orientation of A9-A10 dopaminergic neurons.

CXCL12/CXCR4 signaling has been reported to regulate three essential processes for the establishment of neural networks in different neuronal systems: neuronal migration, cell positioning and axon wiring. However, it is not known whether it regulates the development of A9-A10 tyrosine hydroxylase positive (TH(+)) midbrain dopaminergic (mDA) neurons. We report here that Cxcl12 is expressed in the meninges surrounding the ventral midbrain (VM), whereas CXCR4 is present in NURR1(+) mDA precursors and mDA neurons from E10.

Cxcr7 controls neuronal migration by regulating chemokine responsiveness.

The chemokine Cxcl12 binds Cxcr4 and Cxcr7 receptors to control cell migration in multiple biological contexts, including brain development, leukocyte trafficking, and tumorigenesis. Both receptors are expressed in the CNS, but how they cooperate during migration has not been elucidated. Here, we used the migration of cortical interneurons as a model to study this process.

Chemokine signaling controls intracortical migration and final distribution of GABAergic interneurons.

Functioning of the cerebral cortex requires the coordinated assembly of circuits involving glutamatergic projection neurons and GABAergic interneurons. Although much is known about the migration of interneurons from the subpallium to the cortex, our understanding of the mechanisms controlling their precise integration within the cortex is still limited. Here, we have investigated in detail the behavior of GABAergic interneurons as they first enter the developing cortex by using time-lapse videomicroscopy, slice culture, and in utero experimental manipulations and analysis of mouse mutants.