A GABAergic Maf-expressing interneuron subset regulates the speed of locomotion in Drosophila

This work was funded by grants from INSERM and a 3-year Ph.D. funding from the Association Française contre les Myopathies (AFM) for H.B (Doctoral funding n°19408) and from ANR (17-CE37-0019) for T.J.Interneurons (INs) coordinate motoneuron activity to generate appropriate patterns of muscle contractions, providing animals with the ability to adjust their body posture and to move over a range of speeds. In Drosophila larvae several IN subtypes have been morphologically described and their function well documented. However, the general lack of molecular characterization of those INs prevents the identification of evolutionary counterparts in other animals, limiting our understanding of the principles underlying neuronal circuit organization and function. Here we characterize a restricted subset of neurons in the nerve cord expressing the Maf transcription factor Traffic Jam (TJ). We found that TJ+ neurons are highly diverse and selective activation of these different subtypes disrupts larval body posture and induces specific locomotor behaviors. Finally, we show that a small subset of TJ+ GABAergic INs, singled out by the expression of a unique transcription factors code, controls larval crawling speed.Publisher PDFPeer reviewe

Coe Genes Are Expressed in Differentiating Neurons in the Central Nervous System of Protostomes

Genes of the coe (collier/olfactory/early B-cell factor) family encode Helix-Loop-Helix transcription factors that are widely conserved in metazoans and involved in many developmental processes, neurogenesis in particular. Whereas their functions during vertebrate neural tube formation have been well documented, very little is known about their expression and role during central nervous system (CNS) development in protostomes. Here we characterized the CNS expression of coe genes in the insect Drosophila melanogaster and the polychaete annelid Platynereis dumerilii, which belong to different subgroups of protostomes and show strikingly different modes of development. In the Drosophila ventral nerve cord, we found that the Collier-expressing cells form a subpopulation of interneurons with diverse molecular identities and neurotransmitter phenotypes. We also demonstrate that collier is required for the proper differentiation of some interneurons belonging to the Eve-Lateral cluster. In Platynereis dumerilii, we cloned a single coe gene, Pdu-coe, and found that it is exclusively expressed in post mitotic neural cells. Using an original technique of in silico 3D registration, we show that Pdu-coe is co-expressed with many different neuronal markers and therefore that, like in Drosophila, its expression defines a heterogeneous population of neurons with diverse molecular identities. Our detailed characterization and comparison of coe gene expression in the CNS of two distantly-related protostomes suggest conserved roles of coe genes in neuronal differentiation in this clade. As similar roles have also been observed in vertebrates, this function was probably already established in the last common ancestor of all bilaterians

Abuse of Dominance in Technology-Enabled Markets: Established Standards Reconsidered?

This paper seeks to examine whether the legal standards underpinning the application of Article 102 of the Treaty on the Functioning of the European Union (TFEU) need to be revisited in light of the alleged specificities of “technology-enabled” markets. To this end, the paper is divided in seven parts. Following this short introduction (A), the paper offers first a definition of the very notion of “technology-enabled” markets (B). Then, it questions whether competition agencies should depart from conventional enforcement techniques when reviewing conduct in fast-moving, technology-enabled markets, and follow new, expedited enforcement procedures as proposed recently by several high-ranking officials (C). After this, the paper turns to substantive issues. It begins by reviewing the intricacies of market definition and dominance in technology-enabled markets (D). It then offers some general thoughts on whether a new, general legal standard for a determination of unlawful abuse is needed in technology enabled markets (E). Finally, the paper considers six categories of abusive conduct in the high-tech sector and shows that, faced with a variety of applicable legal standards for each of them, competition agencies, courts and plaintiffs have – understandably – almost always invoked and applied the loosest possible test in support of their allegations or findings. We suggest, in turn, that under existing case-law stricter standards could and should be applied, and that this is particularly important in the context of technology-enabled markets for the simple reason that it is in these markets that the most common pitfalls and shortcomings of the EU law on abuse of a dominant position are magnified (F)