Institut Jacques Monod Seminar – Joaquín Navajas Acedo

Invited by the Greenberg Lab and the Konstantinides Lab, Joaquín Navajas Acedo (Postdoc, Schier Lab at the University of Basel, Switzerland) will present an Institut Jacques Monod seminar on the theme:

Spatiotemporal Emergence of Somatosensory Neuron Diversity

Abstract:

My work uses a population of somatosensory neurons in the zebrafish spinal cord -the Rohon-Beard (RB) neurons- to address a fundamental question in neuroscience: How do cellular factors combine in space and time to generate robustly the diverse neuron types of a functional circuit?Live imaging and deep single-cell transcriptomics across development show that contrary to a ~150-year-old assumption, RB neurons do not disappear by programmed cell death and are heterogeneous at 3 levels: their transcriptome, their axial distribution, and inter-individual pattern. Combining in toto cell lineage reconstruction and a custom whole-mount spatial transcriptomics —in the same animal- my work shows RB neurons possess extremely simple cell lineages and link them to dozens of transcription factors and somatosensory genes in space. Spatiotemporal analysis of RB subtype emergence reveals that it follows a staggered-layer logic, with a ‘pan-RB program’ preceding a stochastic ‘hybrid neurotrophin receptor’ state that resolves into mutually-exclusive subclasses, followed by specialized functional subtypes.  I also define the regulatory mechanism by transcription factors underlying the seemingly stochastic, yet robust emergence of the observed neuronal subtypes across time. I also discuss this mechanism is likely conserved across Anamniotes. This work demonstrates that zebrafish RB neurons are an excellent model to study the precise molecular mechanisms underlying the development of neuron diversity at the single-cell level.