# Targeting of sensory axons in the olfactory bulb

> **NIH NIH R01** · UNIVERSITY OF PENNSYLVANIA · 2024 · $501,127

## Abstract

PROJECT SUMMARY/ABSTRACT
The objective of this proposal is to understand how the first elements of olfactory circuitry are correctly wired
together during embryonic development. Odorant sensing neurons project axons from the olfactory epithelium
to the olfactory bulb in the brain. Each olfactory sensory neuron in the epithelium chooses a single odorant
receptor to express from a very large gene repertoire. Remarkably, all the sensory neurons that have chosen
the same odorant receptor to express extend axons that converge together in specific reproducible locations
within the olfactory bulb. This research proposal addresses how olfactory sensory axons locate their specific
targets in the brain. This project takes advantage of the relative simplicity of the zebrafish olfactory system and
its developmental and experimental accessibility to study the guidance of sensory neurons between the
olfactory epithelium and the bulb. In the first Aim, single cell RNA sequencing is used to identify cell surface or
secreted proteins that are differentially expressed between groups of olfactory sensory neurons whose axons
target different and distinct regions in the olfactory bulb. These are candidate genes involved in targeting, and
their function will be assessed by knocking them down one at a time and testing whether OSN axons target
their correct locations in the olfactory bulb. In the second Aim, we will examine the role an important family of
axon guidance cues, the slits, play in directing olfactory sensory axons to their appropriate target regions in the
bulb. These studies build towards a systems level understanding of how an important functional circuit is
assembled during development. This knowledge will be essential in the formulation of therapies for the
regeneration and repair of olfactory circuitry in aging or anosmic patients.

## Key facts

- **NIH application ID:** 10878439
- **Project number:** 2R01DC012854-11A1
- **Recipient organization:** UNIVERSITY OF PENNSYLVANIA
- **Principal Investigator:** JONATHAN A RAPER
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $501,127
- **Award type:** 2
- **Project period:** 2013-07-08 → 2027-05-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10878439

## Citation

> US National Institutes of Health, RePORTER application 10878439, Targeting of sensory axons in the olfactory bulb (2R01DC012854-11A1). Retrieved via AI Analytics 2026-07-02 from https://api.ai-analytics.org/grant/nih/10878439. Licensed CC0.

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