Tau, C. | bioRxiv Science

bioRxiv2025

A spatial code governs olfactory receptor choice and aligns sensory maps in the nose and brain

Although topographical maps organize many peripheral sensory systems, it remains unclear whether olfactory sensory neurons (OSNs) choose which of the [~]1100 odor receptors (ORs) to express based upon their spatial location in the olfactory epithelium (OE) or instead ORs are scattered randomly. Here we reveal that each OR is expressed at a precise mean position along the OE dorsoventral axis, thereby instantiating a receptor map. This patterning reflects the differential use, by precursors and mature OSNs, of a coherent gene expression program controlled by a spatially-varying retinoic acid gradient; this program -- which includes key transcription factors and axon guidance genes -- translates position into a spatially appropriate distribution of OR choices and aligns the epithelial map of OR identity with the glomerular map present in the olfactory bulb. These results identify a transcriptional code that distinguishes and spatially organizes the vast array of sensory channels that comprise the olfactory system.

neuroscience↗

bioRxiv2024

Rewriting endogenous human transcripts with trans-splicing

Splicing bridges the gap between static DNA sequence and the diverse and dynamic set of protein products that execute a genes biological functions. While exon skipping technologies enable influence over splice site selection, many desired perturbations to the transcriptome require replacement or addition of exogenous exons to target mRNAs: for example, to replace disease-causing exons, repair truncated proteins, or engineer protein fusions. Here, we report the development of RNA-guided trans-splicing with Cas editor (RESPLICE), inspired by the rare, natural process of trans-splicing that joins exons from two distinct primary transcripts. RESPLICE uses two orthogonal RNA-targeting CRISPR effectors to co-localize a trans-splicing pre-mRNA and to inhibit the cis-splicing reaction, respectively. We demonstrate efficient, specific, and programmable trans-splicing of multi-kilobase RNA cargo into nine endogenous transcripts across two human cell types, achieving up to 45% trans-splicing efficiency in bulk, or 90% when sorting for high effector expression. Our results present RESPLICE as a new mode of RNA editing for fine-tuned and transient control of cellular programs without permanent alterations to the genetic code.

molecular biology↗