Université de Fribourg

Mms19 promotes spindle microtubule assembly in Drosophila neural stem cells

Chippalkatti, Rohan ; Egger, Boris ; Suter, Beat

In: PLOS Genetics, 2020, vol. 16, no. 11, p. e1008913

Mitotic divisions depend on the timely assembly and proper orientation of the mitotic spindle. Malfunctioning of these processes can considerably delay mitosis, thereby compromising tissue growth and homeostasis, and leading to chromosomal instability. Loss of functional Mms19 drastically affects the growth and development of mitotic tissues in Drosophila larvae and we now demonstrate that...

Université de Fribourg

Compartment and cell-type specific hypoxia responses in the developing Drosophila brain

Baccino-Calace, Martin ; Prieto, Daniel ; Cantera, Rafael ; Egger, Boris

In: Biology Open, 2020, vol. 9, no. 8, p. -

Environmental factors such as the availability of oxygen are instructive cues that regulate stem cell maintenance and differentiation. We used a genetically encoded biosensor to monitor the hypoxic state of neural cells in the larval brain of Drosophila. The biosensor reveals brain compartment and cell-type specific levels of hypoxia. The values correlate with differential tracheolation that...

Université de Fribourg

Injured axons instruct schwann cells to build constricting actin spheres to accelerate axonal disintegration

Vaquié, Adrien ; Sauvain, Alizée ; Duman, Mert ; Nocera, Gianluigi ; Egger, Boris ; Meyenhofer, Felix ; Falquet, Laurent ; Bartesaghi, Luca ; Chrast, Roman ; Lamy, Christophe Maurice ; Bang, Seokyoung ; Lee, Seung-Ryeol ; Jeon, Noo Li ; Ruff, Sophie ; Jacob, Claire

In: Cell Reports, 2019, vol. 27, no. 11, p. 3152-3166.e7

After a peripheral nerve lesion, distal ends of injured axons disintegrate into small fragments that are subsequently cleared by Schwann cells and later by macrophages. Axonal debris clearing is an early step of the repair process that facilitates regeneration. We show here that Schwann cells promote distal cut axon disintegration for timely clearing. By combining cell-based and in vivo...

Université de Fribourg

Multiple neurons encode CrebB dependent appetitive long-term memory in the mushroom body circuit

Widmer, Yves F. ; Fritsch, Cornelia ; Jungo, Magali M. ; Almeida, Silvia ; Egger, Boris ; Sprecher, Simon G.

In: eLife, 2018, vol. 7, p. e39196

Lasting changes in gene expression are critical for the formation of long-term memories (LTMs), depending on the conserved CrebB transcriptional activator. While requirement of distinct neurons in defined circuits for different learning and memory phases have been studied in detail, only little is known regarding the gene regulatory changes that occur within these neurons. We here use the...

Université de Fribourg

Dynamic Notch signalling regulates neural stem cell state progression in the Drosophila optic lobe

Contreras, Esteban G. ; Egger, Boris ; Gold, Katrina S. ; Brand, Andrea H.

In: Neural Development, 2018, vol. 13, no. 1, p. 25

Neural stem cells generate all of the neurons and glial cells in the central nervous system, both during development and in the adult to maintain homeostasis. In the Drosophila optic lobe, neuroepithelial cells progress through two transient progenitor states, PI and PII, before transforming into neuroblasts. Here we analyse the role of Notch signalling in the transition from neuroepithelial...

Université de Fribourg

Patterning mechanisms diversify neuroepithelial domains in the Drosophila optic placode

Mishra, Abhishek Kumar ; Bernardo-Garcia, F. Javier ; Fritsch, Cornelia ; Humberg, Tim-Henning ; Egger, Boris ; Sprecher, Simon G.

In: PLOS Genetics, 2018, vol. 14, no. 4, p. e1007353

The central nervous system develops from monolayered neuroepithelial sheets. In a first step patterning mechanisms subdivide the seemingly uniform epithelia into domains allowing an increase of neuronal diversity in a tightly controlled spatial and temporal manner. In Drosophila, neuroepithelial patterning of the embryonic optic placode gives rise to the larval eye primordium, consisting of...

Université de Fribourg

A genetically encoded biosensor for visualising hypoxia responses in vivo

Misra, Tvisha ; Baccino-Calace, Martin ; Meyenhofer, Felix ; Rodriguez-Crespo, David ; Akarsu, Hatice ; Armenta-Calderón, Ricardo ; Frei, Thomas A. Gorr, Christian ; Cantera, Rafael ; Egger, Boris ; Luschnig, Stefan

In: Biology Open, 2017, vol. 6, no. 2, p. 296–304

Cells experience different oxygen concentrations depending on location, organismal developmental stage, and physiological or pathological conditions. Responses to reduced oxygen levels (hypoxia) rely on the conserved hypoxia-inducible factor 1 (HIF-1). Understanding the developmental and tissue-specific responses to changing oxygen levels has been limited by the lack of adequate tools for...

Université de Fribourg

The microcephaly-associated protein Wdr62/CG7337 is required to maintain centrosome asymmetry in Drosophila neuroblasts

Nair, Anjana Ramdas ; Singh, Priyanka ; Garcia, David Salvador ; Rodriguez-Crespo, David ; Egger, Boris ; Cabernard, Clemens

In: Cell Reports, 2016, vol. 14, no. 5, p. 1100–1113

Centrosome asymmetry has been implicated in stem cell fate maintenance in both flies and vertebrates, but the underlying molecular mechanisms are incompletely understood. Here, we report that loss of CG7337, the fly ortholog of WDR62, compromises interphase centrosome asymmetry in fly neural stem cells (neuroblasts). Wdr62 maintains an active interphase microtubule-organizing center (MTOC) by...

Université de Fribourg

In vitro imaging of primary neural cell culture from Drosophila

Egger, Boris ; Giesen, Lena van ; Moraru, Manuela ; Sprecher, Simon G.

In: Nature Protocols, 2013, vol. 8, no. 5, p. 958–965

Cell culture systems are widely used for molecular, genetic and biochemical studies. Primary cell cultures of animal tissues offer the advantage that specific cell types can be studied in vitro outside of their normal environment. We provide a detailed protocol for generating primary neural cell cultures derived from larval brains of Drosophila melanogaster. The developing larval brain contains...