Université de Fribourg

Serial electron microscopic reconstruction of the drosophila larval eye: Photoreceptors with a rudimentary rhabdomere of microvillar-like processes

Hartenstein, Volker ; Yuan, Michaela ; Younossi-Hartenstein, Amelia ; Karandikar, Aanavi ; Bernardo-Garcia, F. Javier ; Sprecher, Simon G. ; Knust, Elisabeth

In: Developmental Biology, 2019, vol. 453, no. 1, p. 56–67

Photoreceptor cells (PRCs) across the animal kingdom are characterized by a stacking of apical membranes to accommodate the high abundance of photopigment. In arthropods and many other invertebrate phyla PRC membrane stacks adopt the shape of densely packed microvilli that form a structure called rhabdomere. PRCs and surrounding accessory cells, including pigment cells and lens-forming cells,...

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

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

Genetic control of photoreceptor terminal differentiation in Drosophila melanogaster

Bernardo-Garcia, F. Javier ; Sprecher, Simon (Dir.)

Thèse de doctorat : Université de Fribourg, 2018 ; no. 2066.

Why do photoreceptors differentiate in the eye? Though simple, biologically this is an important question, and it may prove complex to answer. To present a bigger picture: animals have evolved a diversity of highly specialised sensory organs, which they use to obtain information from their environment and thus survive. These organs contain different types of receptor neurons. For example, there...

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 brain regeneration in the acoel worm Symsagittifera roscoffensis

Sprecher, Simon G. ; Bernardo-Garcia, F. Javier ; Giesen, Lena van ; Hartenstein, Volker ; Reichert, Heinrich ; Neves, Ricardo ; Bailly, Xavier ; Martinez, Pedro ; Brauchle, Michael

In: Biology Open, 2015, vol. 4, no. 12, p. 1688–1695

The ability of some animals to regrow their head and brain after decapitation provides a striking example of the regenerative capacity within the animal kingdom. The acoel worm Symsagittifera roscoffensis can regrow its head, brain and sensory head organs within only a few weeks after decapitation. How rapidly and to what degree it also reacquires its functionality to control behavior however...