Université de Fribourg

Oriented basement membrane fibrils provide a memory for F-actin planar polarization via the Dystrophin-Dystroglycan complex during tissue elongation

Cerqueira Campos, Fabiana ; Dennis, Cynthia ; Alégot, Hervé ; Fritsch, Cornelia ; Isabella, Adam ; Pouchin, Pierre ; Bardot, Olivier ; Horne-Badovinac, Sally ; Mirouse, Vincent

In: Development, 2020, vol. 147, no. 7, p. dev186957

How extracellular matrix contributes to tissue morphogenesis is still an open question. In the Drosophila ovarian follicle, it has been proposed that after Fat2-dependent planar polarization of the follicle cell basal domain, oriented basement membrane (BM) fibrils and F-actin stress fibers constrain follicle growth, promoting its axial elongation. However, the relationship between BM fibrils...

Université de Fribourg

Multilevel regulation of the glass locus during Drosophila eye development

Fritsch, Cornelia ; Bernardo-Garcia, F. Javier ; Humberg, Tim-Henning ; Mishra, Abhishek Kumar ; Miellet, Sara ; Almeida, Silvia ; Frochaux, Michael V. ; Deplancke, Bart ; Huber, Armin ; Sprecher, Simon G.

In: PLOS Genetics, 2019, vol. 15, no. 7, p. e1008269

Development of eye tissue is initiated by a conserved set of transcription factors termed retinal determination network (RDN). In the fruit fly Drosophila melanogaster, the zinc-finger transcription factor Glass acts directly downstream of the RDN to control identity of photoreceptor as well as non-photoreceptor cells. Tight control of spatial and temporal gene expression is a critical...

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

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

Successive requirement of Glass and Hazy for photoreceptor specification and maintenance in Drosophila

Bernardo-Garcia, F. Javier ; Humberg, Tim-Henning ; Fritsch, Cornelia ; Sprecher, Simon G.

In: Fly, 2017, vol. 11, no. 2, p. 112–120

Development of the insect compound eye requires a highly controlled interplay between transcription factors. However, the genetic mechanisms that link early eye field specification to photoreceptor terminal differentiation and fate maintenance remain largely unknown. Here, we decipher the function of 2 transcription factors, Glass and Hazy, which play a central role during photoreceptor...

Université de Fribourg

The transcription factor Glass links eye field specification with photoreceptor differentiation in Drosophila

Bernardo-Garcia, F. Javier ; Fritsch, Cornelia ; Sprecher, Simon G.

In: Development, 2016, vol. 143, no. 8, p. 1413–1423

Eye development requires an evolutionarily conserved group of transcription factors, termed the retinal determination network (RDN). However, little is known about the molecular mechanism by which the RDN instructs cells to differentiate into photoreceptors. We show that photoreceptor cell identity in Drosophila is critically regulated by the transcription factor Glass, which is primarily...

Université de Fribourg

Functional genomics identifies regulators of the phototransduction machinery in the Drosophila larval eye and adult ocelli

Mishra, Abhishek Kumar ; Bargmann, Bastiaan O.R. ; Tsachaki, Maria ; Fritsch, Cornelia ; Sprecher, Simon G.

In: Developmental Biology, 2016, vol. 410, no. 2, p. 164–177

Sensory perception of light is mediated by specialized Photoreceptor neurons (PRs) in the eye. During development all PRs are genetically determined to express a specific Rhodopsin (Rh) gene and genes mediating a functional phototransduction pathway. While the genetic and molecular mechanisms of PR development is well described in the adult compound eye, it remains unclear how the expression of...

Université de Fribourg

Dynamic conformational transitions of the EGF receptor in living mammalian cells determined by FRET and fluorescence lifetime imaging microscopy

Ziomkiewicz, Iwona ; Loman, Anastasia ; Klement, Reinhard ; Fritsch, Cornelia ; Klymchenko, Andrey S. ; Bunt, Gertrude ; Jovin, Thomas M. ; Arndt-Jovin, Donna J.

In: Cytometry Part A, 2013, vol. 83, no. 9, p. 794–805

We have revealed a reorientation of ectodomain I of the epidermal growth factor receptor (EGFR; ErbB1; Her1) in living CHO cells expressing the receptor, upon binding of the native ligand EGF. The state of the unliganded, nonactivated EGFR was compared to that exhibited after ligand addition in the presence of a kinase inhibitor that prevents endocytosis but does not interfere with binding or the...