Biology subjects

Tischbirek, C. H.

Publications and source records attributed to Tischbirek, C. H..

4 recordsLinked to original sources

bioRxiv2026

Whole-organism spatial transcriptomics at single-cell resolution in C. elegans

Spatial transcriptomics has advanced our understanding of tissue organization by mapping gene expression in its native context yet applying these techniques to whole organisms remains a significant challenge. Caenorhabditis elegans is well-suited to whole organism-level analysis because its compact size, transparency, reproducible anatomy, and genetic tractability make it possible to link molecular and cellular changes to circuit function and behavior within the same animal. However, current transcriptomic approaches in C. elegans are often limited by spatial resolution or multiplexing capacity, making it challenging to profile multiple gene expression patterns across intact worms while preserving spatial context. Here, we present a single-molecule fluorescence in situ hybridization workflow that enables multiplex imaging with single-cell resolution across the entire worm. This approach allows sequential imaging of one gene per fluorescent channel using two channels across 20 hybridization rounds, enabling the profiling of up to 40 genes while preserving spatial context. We further provide a curated marker-gene panel for reproducible neuron identification, which, together with probabilistic assignment of transcripts to segmented nuclei, enables quantitative measurements of gene expression levels. We used this method to identify up to 86 neuronal classes and reveal sex- and neuron-specific expression patterns at single-cell resolution. Together, these results establish a scalable framework for the spatial analysis of gene expression and cell identity in intact C. elegans.

neuroscience↗

bioRxiv2025

Synaptic MEMOIR: mapping individual synapses of neurons with protein barcodes

Obtaining wiring diagrams of brains has been a major achievement for neuroscience. However, an underlying challenge in connectomics is the fundamental tradeoff between the imaging resolution needed to resolve synapses and the volume of the brain that can be imaged. For example, electron microscopy (EM) visualizes synaptic sites with ~5 nm resolution, but is difficult to scale beyond volumes of 1 mm3. Here, we present Synaptic MEMOIR (Memory with Engineered Mutagenesis with Optical in situ Readout) that enables imaging of neuronal projections in animal brains with single-synapse resolution. Synaptic MEMOIR is built around three key design features. First, protein barcodes are transported to synapses to allow matching of synaptic barcodes to cell body barcodes without high resolution imaging and the error-prone process of tracing neuronal processes across long distances. Second, Synaptic MEMOIR uses continuous mutagenesis to generate a large diversity of barcodes to uniquely label cell bodies and synapses. Last, the timing of recombination and transport can be tuned to record synaptic age or projection information. Combining these features, we demonstrated projection mapping of 113 neurons in the Drosophila melanogaster optic lobe in a volume of 9.5 million m3. Because synapses are identified by transported barcodes with optical microscopy at 300 nm resolution, this approach can potentially scale to much larger volumes, similar at least to those imaged in recent mouse brain transcriptomics atlases. In addition, synaptic MEMOIR can match barcodes across brain sections, and does not require tissue clearing to track long-range projections. Together, these results provide the foundation for a scalable optical image-based system for reconstructing the neural wiring diagrams of brains across different developmental stages, genetic backgrounds and perturbations. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=46 SRC="FIGDIR/small/690442v1_ufig1.gif" ALT="Figure 1"> View larger version (14K): org.highwire.dtl.DTLVardef@8363cdorg.highwire.dtl.DTLVardef@d3240org.highwire.dtl.DTLVardef@5e2793org.highwire.dtl.DTLVardef@1784f2a_HPS_FORMAT_FIGEXP M_FIG C_FIG

neuroscience↗

bioRxiv2025

Spatial Proofreading Amplification of in situ Transcript and Protein Signals

Spatial transcriptomics experiments greatly benefit from brighter signals that improve detection efficiency and shorten imaging times. Here, we introduce a new enzyme-free signal amplification method inspired by the kinetic proofreading principle, in which short oligonucleotide probes are iteratively deposited at their target site and covalently photo-crosslinked to the cell, forming highly stable DNA assemblies. The method results in more than 500-fold signal amplification and supports multiplex readout capabilities.

molecular biology↗

bioRxiv2025

The forkhead transcription factor FKH-7/FOXP acts in chemosensory neurons to regulate developmental decision-making

Autism is a complex neurodevelopmental disorder with many associated genetic factors, including the forkhead transcription factor FOXP1. Although FOXP1s neuronal role is well-studied, the specific molecular consequences of different FOXP1 pathogenic variants in physiologically-relevant contexts are unknown. Here we ascribe the first function to Caenorhabditis elegans FKH-7/FOXP, which acts in two chemosensory neuron classes to promote the larval decision to enter the alternative, developmentally-arrested dauer life stage. We demonstrate that human FOXP1 can functionally substitute for C. elegans FKH-7 in these neurons and that engineering analogous FOXP1 hypomorphic missense mutations in the endogenous fkh-7 locus also impairs developmental decision-making. In a fkh-7/FOXP1 missense variant, single-cell transcriptomics identifies downregulated expression of autism-associated kcnl-2/KCNN2 calcium-activated potassium channel in a serotonergic sensory neuron. Our findings establish a novel framework linking two evolutionarily-conserved autism-associated genes for deeper characterization of variant-specific molecular pathology at single neuron resolution in the context of a developmental decision-making paradigm.

neuroscience↗