Biology subjects

D'Arcy, B.

Publications and source records attributed to D'Arcy, B..

4 recordsLinked to original sources

bioRxiv2026

Chd8 haploinsufficiency leads to molecular layer heterotopias and age-dependent cortical expansion

Mutations in the chromatin remodeler CHD8 are associated with autism and macrocephaly. While mouse models of Chd8 haploinsufficiency recapitulate brain overgrowth, the specific cellular mechanisms and developmental timing that lead to these anatomical abnormalities remain poorly understood. Here, we conducted 3D imaging of Chd8V986*/+ mouse brains using magnetic resonance imaging followed by tissue clearing and cellular resolution light-sheet microscopy across embryonic and postnatal developmental stages. We found that brain overgrowth occurs postnatally, driven by an increase in non-neuronal cells prior to volumetric expansion. Unexpectedly, we identified prevalent molecular layer heterotopias (MLH) within the frontal cortex of Chd8V986*/+ mice composed of neurons breaking through the pial surface during embryonic development and persisting throughout life. Increased incidence of MLH, previously identified in individuals with idiopathic autism, was replicated across three independent Chd8+/- mouse models and present across multiple genomic backgrounds, establishing aberrant neuronal migration as a core feature of Chd8 haploinsufficiency.

neuroscience↗

bioRxiv2025

Dissecting mammalian cortical circuit development at single-cell resolution using inducible barcoded rabies virus

Highly organized circuits of connected neurons enable diverse brain functions. Improper development of these circuits is associated with neurodevelopmental disorders, and understanding how circuits are formed is crucial for unraveling the mechanisms of these diseases. We currently have an incomplete picture of how specific brain circuits develop and how they are affected in disease, because we lack methods to study them at scale and with single-cell resolution. Monosynaptic rabies tracing is the gold standard method to study circuit architecture. However, it suffers from cellular toxicity, low throughput, lack of control over the timing of labeling, and the inability to access the molecular profiles of individual neurons. To address these issues, we developed an inducible barcoded rabies virus (ibRV) to enable temporal-controlled labeling of synaptic circuits followed by high-throughput single-cell genomics readout. ibRV allows for dissecting neuronal circuit changes over time at single-cell and spatial resolution. We applied ibRV to study the development of specific mouse cortical circuits during late prenatal and postnatal life using single-cell genomics and unbiased spatial transcriptomics as readouts. We characterized and quantified developmental connectivity patterns and molecular cascades that underlie their formation. Additionally, we constructed functional in silico circuit models that enable interrogation of circuit function and dysfunction at specific developmental stages. Our study provides novel tools for circuit analysis and can provide new insights into the mechanisms of mammalian brain development.

neuroscience↗

bioRxiv2025

Subcellular transcriptome of radial glia reveals compartmentalized control of cortical development

RNA localization and local translation mediate spatial and temporal control of polarized cells, including radial glial cells (RGCs) which produce and organize neurons and glia. Within RGCs, RNAs are transported long distances to basal endfeet, where they can undergo local translation. However, the subcellular composition of RGCs and function of local gene regulation remains largely unknown. Here, we discover that basal endfeet harbor a rich transcriptome including a Dynein component critical for subcellular RGC function. By purifying RGC compartments in vivo, we discover [~]3000 endfoot transcripts, including [~]800 highly enriched compared to cell bodies. Many endfoot-enriched transcripts exhibit conserved subcellular localization in neurons and glia and are associated with neurodevelopmental disease. We show that endfoot-enriched Dync1li2 regulates RGC basal morphology and subsequently interneuron organization. Finally, we develop LOCAL-KD, a CRISPR-Cas13 based method for subcellular mRNA knockdown in vivo. Leveraging this, we demonstrate that endfoot-localized Dync1li2 is critical for RGC morphology. Our study establishes experimental paradigms to understand RNA localization in the nervous system. Moreover, we discover RGCs have a vast subcellular transcriptome, revealing foundational insights into how RGCs control cortical development.

neuroscience↗

bioRxiv2022

Subcellular proteome of radial glia reveals non-muscle myosins control basal endfeet to mediate interneuron organization

Radial glial cells (RGCs) are essential for the generation and organization of neurons in the cerebral cortex. RGCs have an elongated bipolar morphology with basal and apical endfeet which reside in distinct niches. Yet, how this subcellular compartmentalization of RGCs controls cortical development is largely unknown. Here, we employ in vivo proximity labeling using unfused BirA to generate the first subcellular proteome of RGCs and uncover new principles governing local control of cortical development. We discover a cohort of proteins that are significantly enriched in RGC basal endfeet, with MYH9 and MYH10 among the most abundant. Myh9 and Myh10 transcripts also localize to endfeet with distinct temporal dynamics. Although they each encode isoforms of non-muscle myosin II heavy chain, Myh9 and Myh10 have drastically different requirements for RGC integrity. Myh9 loss from RGCs decreases branching complexity and causes endfoot protrusion through the basement membrane. In contrast, Myh10 controls endfoot adhesion, as mutants have unattached apical and basal endfeet. Finally, we show that Myh9- and Myh10-mediated regulation of RGC complexity and endfoot position non-cell autonomously controls interneuron number and organization in the marginal zone. Our study demonstrates the utility of in vivo proximity labeling for dissecting local control of complex systems, and reveals new mechanisms for dictating RGC integrity and cortical architecture.

neuroscience↗