Université de Fribourg

Altering the temporal regulation of one transcription factor drives evolutionary trade-offs between head sensory organs

Ramaekers, Ariane ; Claeys, Annelies ; Kapun, Martin ; Mouchel-Vielh, Emmanuèle ; Potier, Delphine ; Weinberger, Simon ; Grillenzoni, Nicola ; Dardalhon-Cuménal, Delphine ; Yan, Jiekun ; Wolf, Reinhard ; Flatt, Thomas ; Buchner, Erich ; Hassan, Bassem A.

In: Developmental Cell, 2019, vol. 50, no. 6, p. 780-792.e7

Size trade-offs of visual versus olfactory organs is a pervasive feature of animal evolution. This could result from genetic or functional constraints. We demonstrate that head sensory organ size trade-offs in Drosophila are genetically encoded and arise through differential subdivision of the head primordium into visual versus non- visual fields. We discover that changes in the temporal...

Université de Fribourg

Complex behavioural changes after odour exposure in Drosophila larvae

Colomb, Julien ; Grillenzoni, Nicola ; Stocker, Reinhard F. ; Ramaekers, Ariane

A variety of odorants attract Drosophila larvae, although this behaviour can be modulated by experience. For instance, larvae pre-exposed to an attractive odorant may subsequently display less attraction towards the same compound. In previous reports, this phenomenon has been interpreted as a drop in olfactory sensitivity, caused by sensory adaptation. We tried to elucidate the basis of...

Université de Fribourg

Architecture of the primary taste center of Drosophila melanogaster larvae

Colomb, Julien ; Grillenzoni, Nicola ; Ramaekers, Ariane ; Stocker, Reinhard F.

In: The Journal of Comparative Neurology, 2007, vol. 502, no. 5, p. 834-837

A simple nervous system combined with stereotypic behavioral responses to tastants, together with powerful genetic and molecular tools, have turned Drosophila larvae into a very promising model for studying gustatory coding. Using the Gal4/UAS system and confocal microscopy for visualizing gustatory afferents, we provide a description of the primary taste center in the larval central nervous...

Université de Fribourg

Glomerular Maps without Cellular Redundancy at Successive Levels of the Drosophila Larval Olfactory CircuitGlomerular Maps without Cellular Redundancy at Successive Levels of the Drosophila Larval Olfactory Circuit

Ramaekers, Ariane ; Magnenat, Edwige ; Marin, Elizabeth C. ; Gendre, Nanaë ; Jefferis, Gregory S.X.E. ; Luo, Liqun ; Stocker, Reinhard F.

In: Current Biology, 2005, vol. 15(11), p. 982

Background: Drosophila larvae possess only 21 odorant-receptor neurons (ORNs), whereas adults have 1,300. Does this suggest that the larval olfactory system is built according to a different design than its adult counterpart, or is it just a miniature version thereof? Results: By genetically labeling single neurons with FLP-out and MARCM techniques, we...

Université de Fribourg

Integration of complex larval chemosensory organs into the adult nervous system of Drosophila

Gendre, Nanaë ; Lüer, Karin ; Friche, Sandrine ; Grillenzoni, Nicola ; Ramaekers, Ariane ; Technau, Gerhard M. ; Stocker, Reinhard F.

In: Development, 2004, vol. 131, p. 83-92

The sense organs of adult Drosophila, and holometabolous insects in general, derive essentially from imaginal discs and hence are adult specific. Experimental evidence presented here, however, suggests a different developmental design for the three largely gustatory sense organs located along the pharynx. In a comprehensive cellular analysis, we show that the posteriormost of the three organs...

Université de Fribourg

Developmental origin of wiring specificity in the olfactory system of Drosophila

Jefferis, Gregory S. X. E. ; Vyas, Raj M. ; Berdnik, Daniela ; Ramaekers, Ariane ; Stocker, Reinhard F. ; Tanaka, Nobuaki K. ; Ito, Kei ; Luo, Liqun

In: Development, 2004, vol. 131, p. 117-130

In both insects and mammals, olfactory receptor neurons (ORNs) expressing specific olfactory receptors converge their axons onto specific glomeruli, creating a spatial map in the brain. We have previously shown that second order projection neurons (PNs) in Drosophila are prespecified by lineage and birth order to send their dendrites to one of ~50 glomeruli in the antennal lobe. How can a given...