Biology subjects

Jabaudon, D.

Publications and source records attributed to Jabaudon, D..

5 recordsLinked to original sources

bioRxiv2018

Single-cell transcriptional dynamics and origins of neuronal diversity in the developing mouse neocortex

During cortical development, distinct subtypes of glutamatergic neurons are sequentially born and differentiate from dynamic populations of progenitors. The neurogenic competence of these progenitors progresses as corticogenesis proceeds; likewise, newborn neurons transit through sequential states as they differentiate. Here, we trace the developmental transcriptional trajectories of successive generations of apical progenitors (APs) and isochronic cohorts of their daughter neurons using parallel single-cell RNA sequencing between embryonic day (E) 12 and E15 in the mouse cerebral cortex. Our results identify the birthdate- and differentiation stage-related transcriptional dynamics at play during corticogenesis. As corticogenesis proceeds, APs transit through embryonic age-dependent molecular states, which are transmitted to their progeny to generate successive initial daughter cell identities. In neurons, essentially conserved post-mitotic differentiation programs are applied onto these distinct AP-derived ground states, allowing temporally-regulated sequential emergence of specialized neuronal cell types. Molecular temporal patterning of sequentially-born daughter neurons by their respective mother cell thus underlies emergence of neuronal diversity in the neocortex.\n\nOne Sentence SummaryDuring corticogenesis, temporally dynamic molecular birthmarks are transmitted from progenitors to their post-mitotic progeny to generate neuronal diversity.

neuroscience↗

bioRxiv2018

Single-cell molecular connectomics of intracortically-projecting neurons

The neocortex is organized into distinct areas, whose interconnectivity underlies sensorimotor transformations and integration1-7. These behaviorally critical functions are mediated by intracortically-projecting neurons (ICPN), which are a heterogeneous population of cells sending axonal branches to distinct cortical areas as well as to subcortical targets8-10. Although population-based11-14 and single-cell15-19 intracortical wiring diagrams are being identified, the transcriptional signatures corresponding to single-cell axonal projections of ICPN to multiple sites remain unknown. To address this question, we developed a high-throughput approach, \"ConnectID\", to link connectome and transcriptome in single neurons. ConnectID combines MAPseq projection mapping17,20 (to identify single-neuron multiplex projections) with single-cell RNA sequencing (to identify corresponding gene expression). Using primary somatosensory cortex (S1) ICPN as proof-of-principle neurons, we identify three cardinal targets: (1) the primary motor cortex (M1), (2) the secondary somatosensory cortex (S2) and (3) subcortical targets (Sub). Using ConnectID, we identify transcriptional modules whose combined activities reflect multiplex projections to these cardinal targets. Based on these findings, we propose that the combinatorial activity of connectivity-defined transcriptional modules serves as a generic molecular mechanism to create diverse axonal projection patterns within and across neuronal cell types.

neuroscience↗

bioRxiv2018

Simultaneous production of diverse neuronal subtypes during early corticogenesis

The circuits of the neocortex are composed of a broad diversity of neuronal cell types, which can be distinguished by their laminar location, molecular identity, and connectivity. During embryogenesis, successive generations of glutamatergic neurons are sequentially born from progenitors located in germinal zones below the cortex. In this process, the earliest-born generations of neurons differentiate to reside in deep layers, while later-born daughter neurons reside in more superficial layers. Although the aggregate competence of progenitors to produce successive subtypes of neurons progresses as corticogenesis proceeds, a fine-grained temporal understanding of how neuronal subtypes are sequentially produced is still missing. Here, we use FlashTag, a high temporal resolution labeling approach, to follow the fate of the simultaneously-born daughter neurons of ventricular zone progenitors at multiple stages of corticogenesis. Our findings reveal a bimodal regulation in the diversity of neurons being produced at single time points of corticogenesis. Initially, distinct subtypes of deep-layer neurons are simultaneously produced, as defined by their laminar location, molecular identity and connectivity. Later on, instead, instantaneous neuronal production is homogeneous and the distinct superficial-layer neurons subtypes are sequentially produced. These findings suggest that early-born, deep-layer neurons have a less determined fate potential than later-born superficial layer neurons, which may reflect the progressive implementation of pre-and/or post-mitotic mechanisms controlling neuronal fate reliability.

developmental biology↗

bioRxiv2018

A translaminar genetic logic for the circuit identity of intracortically-projecting neurons

Distinct subtypes of intracortically-projecting neurons (ICPN) are present in all layers, allowing propagation of information within and across cortical columns. How the molecular identities of ICPN relate to their defining anatomical and functional properties is unknown. Here we show that the transcriptional identities of ICPN primarily reflect their input-output connectivities rather than their birth dates or laminar positions. Thus, conserved circuit-related transcriptional programs are at play across cortical layers, which may preserve canonical circuit features across development and evolution.

neuroscience↗

bioRxiv2018

In vivo pulse-labeling of isochronic cohorts of cells in the central nervous system using FlashTag

This protocol describes a fluorescence birthdating technique to label, track and isolate isochronic cohorts of newborn cells in the central nervous system in vivo. Injection of carboxyfluorescein esters into the cerebral ventricle allows pulse-labeling of M-phase progenitors in touch with the ventricle and their progeny across the central nervous system, a procedure we termed FlashTag. Labeled cells can be imaged ex vivo or in fixed tissue, targeted for electrophysiological experiments, or isolated using Fluorescence-Activated Cell Sorting (FACS) for cell culture or (single-cell) RNA-sequencing. The dye is retained for several weeks, allowing labeled cells to be identified postnatally. This protocol describes the labeling procedure using in utero injection, the isolation of live cells using FACS, as well as the processing of labeled tissue using immunohistochemistry.

neuroscience↗