Biology subjects

Zagar, Y.

Publications and source records attributed to Zagar, Y..

5 recordsLinked to original sources

bioRxiv2026

Temporal tuning of actin nucleation by the repurposed DNA repair complex RAD51/fignl1 encodes distinct axon guidance decisions

Axon guidance is essential for neural circuit assembly and function. While much of the repertoire of guidance cues and receptors is known, its limited diversity cannot fully explain the remarkable complexity of the brain connectome. How temporally ordered, context-dependent intrinsic programs shape the diversity of axonal responses to guidance signals remains poorly understood. We reveal how non-canonical Wnt5a signalling repurposes the DNA repair complex RAD51/fignl1 as a downstream integrator to control retinal ganglion cell axon decision-making at the midline. We demonstrate that differential RAD51/fignl1 expression and interaction dynamics between ipsilateral and contralateral axons tunes the magnitude and temporal dynamics of F-actin nucleation, thereby encoding their trajectory choice. Our findings establish temporal control of cytoskeletal dynamics as a key determinant of axon decision-making and thereby a fundamental layer of circuit wiring. They provide a potential mechanistic framework linking mutations in the DNA repair gene RAD51 to neurodevelopmental disorders with midline guidance defects.

neuroscience↗

bioRxiv2025

High-Throughput Machine Learning-Aided Antibody Discovery for Cell Surface Antigens

Machine learning (ML) has the potential to revolutionize antibody design and selection, but its success depends on access to extensive, well-curated datasets of antibody-antigen interactions. To address this need, we developed a synthetic Fab yeast display library optimized for seamless ML integration, focusing on sequence diversity within the CDRH3 loop. The library incorporates key sequence features derived from human B cell repertoires essential for efficient antibody generation captured in a compact antigen recognition module (ARM) format. Built using the VH1-69 heavy chain and four light chains, the library was evaluated against ten human and murine cell surface antigens, including PD-L1, TIGIT, and ROBO1. This approach yielded hundreds of antibodies with robust biophysical properties, validated for functional performance in flow cytometry and immunohistochemistry. Furthermore, ML analysis identified additional antibodies for ROBO2 and PD-L2 from the aggregate sequencing data, demonstrating utility for hybrid in silico and experimental workflows. We provide a publicly accessible dataset comprising more than 68,000 Fab sequences and 486 characterized antibodies. This study establishes an ML-compatible framework designed to accelerate and streamline antibody discovery and development.

biophysics↗

bioRxiv2023

Axon guidance during CNS regeneration is required for specific brain innervation

Reconstruction of functional neuronal circuits in the mature brain remains a big challenge in the field of central nervous system (CNS) repair. Despite achievement of robust, long-distance regeneration through modulation of specific neuronal intrinsic growth properties, functional recovery is still limited due to major guidance defects of regenerating axons. Using co-activation of mTOR, JAK/STAT and c-myc pathways in retinal ganglion cells (RGC), we highlight that regenerating axons avoid the suprachiasmatic nucleus (SCN) due to repulsive mechanisms. We show that Slit/Robo guidance signaling is responsible for this reinnervation failure. In vivo suppression of this repulsive signaling allows regenerating axons to enter the SCN. The newly formed circuit is associated with functional behavioral recovery. Our results provide evidence that axon guidance mechanisms are required in the context of mature neuronal circuit repair.

neuroscience↗

bioRxiv2023

Subcellular second messenger networks drive distinct repellent-induced axon behaviors

AO_SCPLOWBSTRACTC_SCPLOWSecond messengers, including cAMP, cGMP and Ca2+ are often placed in an integrating position to combine the extracellular cues that orient growing axons in the developing brain. This view suggests that axon repellents share the same set of cellular messenger signals and that axon attractants evoke opposite cAMP, cGMP and Ca2+ changes. Investigating the confinement of these second messengers in cellular nanodomains, we instead demonstrate that two repellent cues, ephrin-A5 and Slit1, induce spatially segregated signals. These guidance molecules activate subcellular-specific second messenger crosstalks, each signaling network controlling distinct axonal morphology changes in vitro and pathfinding decisions in vivo.

developmental biology↗

bioRxiv2020

The DCC receptor regulates astroglial development essential for telencephalic morphogenesis and corpus callosum formation

The forebrain hemispheres are predominantly separated during embryogenesis by the interhemispheric fissure (IHF). Radial astroglia remodel the IHF to form a continuous substrate between the hemispheres for midline crossing of the corpus callosum (CC) and hippocampal commissure (HC). DCC and NTN1 are molecules that have an evolutionarily conserved function in commissural axon guidance. The CC and HC are absent in Dcc and Ntn1 knockout mice, while other commissures are only partially affected, suggesting an additional aetiology in forebrain commissure formation. Here, we find that these molecules play a critical role in regulating astroglial development and IHF remodelling during CC and HC formation. Human subjects with DCC mutations display disrupted IHF remodelling associated with CC and HC malformations. Thus, axon guidance molecules such as DCC and NTN1 first regulate the formation of a midline substrate for dorsal commissures prior to their role in regulating axonal growth and guidance across it.

neuroscience↗