Development and Evolution of Neuronal Diversity in the Insect Visual System

Host

Christa Rhiner, Stem Cells and Regeneration Lab

Venue

Seminar room

Abstract

The central nervous system consists of thousands to millions of different neuronal types, which form circuits that define its capacity to execute different functions. During embryonic development, this diversity is generated by the interplay of two main mechanisms, spatial and temporal patterning. These mechanisms are driven by the segregated expression of transcription factors in space and time, respectively, that dictate the nature of neuronal cell types that are born from specific progenitors at specific developmental timepoints. How do these mechanisms evolve and how do they affect neuronal diversity? Using the Drosophila melanogaster visual system as a model, we used single-cell mRNA sequencing to identify all temporal transcription factors in the neuronal stem cells and identified the neuronal progeny that are born during each temporal window. This comprehensive analysis of a temporal series of transcription factors offers a proof-of-principle for the use of single-cell mRNA sequencing for the comparison of temporal patterning across different species that can lead to an understanding of how neurodevelopmental mechanisms evolve to generate diverse neuronal types. We are currently expanding these analyses to the developing visual system of different species that span the insect phylogenetic tree. We identify conserved and divergent temporal transcription factors and reconstruct the evolutionary history of a complex gene regulatory network that regulates neuronal diversity. Finally, we attempt to link these evolutionary patterns to their effects in the respective neuronal diversity.

Biography

I am a group leader at the Institut Jacques Monod in Paris, France. I started my group three years ago and our research is focused on the evolution of neurodevelopmental mechanisms, in an effort to understand how the impressive neuronal diversity is generated over the days or weeks of embryonic development and how these developmental mechanisms have evolved over the millions of years of animal evolution. The questions that we address have been shaped by my prior research experience. I got interested in development as an undergraduate student, when I worked on understanding how silkworms regulate the expression of chorion genes during follicle development. During my PhD, I studied the evolution of regenerative capacity using appendage regeneration as a model of the appendage regeneration of an amphipod crustacean, Parhyale hawaiensis. Finally, I got excited by neurobiology during my postdoctoral studies in the lab of Claude Desplan, where I studied the patterning mechanisms that specify neuronal types in Drosophila melanogaster and how neurons acquire their terminal molecular, physiological, and morphological characteristics once they are specified.

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Champalimaud Research (CR) Colloquia Series is a seminar programme organised by the Champalimaud Centre for the Unknown to promote the discussion about the most interesting and significant questions in neuroscience and physiology & cancer with appointed speakers by the CR Community.