ER stress transforms random olfactory receptor choice into axon targeting precision

Area of Science:

• Neuroscience
• Molecular Biology
• Cell Biology

Background:

• Olfactory sensory neurons (OSNs) express one of over 1,000 olfactory receptor (OR) genes.
• Precise axon targeting of OR-specific glomeruli in the olfactory bulb is crucial for olfactory processing.
• The unfolded protein response (UPR) is known for its role in cellular quality control.

Purpose of the Study:

• To investigate the role of the PERK arm of the UPR in OSN axon targeting.
• To understand how OR identity is translated into specific gene expression patterns that guide axon projections.
• To identify molecular mechanisms linking ER stress to axon guidance specificity.

Main Methods:

• Analysis of PERK signaling in OSN development.
• Investigating the impact of OR sequence variations on ER stress.
• Identifying transcription factors involved in OR-dependent gene expression.
• Studying the regulation of axon guidance and cell-adhesion genes.

Main Results:

• The PERK arm of the UPR regulates glomerular coalescence and axon projection specificity.
• Distinct OR protein sequences induce unique ER stress patterns, creating gene expression signatures.
• The transcription factor Ddit3 acts as a key mediator of PERK signaling.
• PERK-mediated ER stress patterns regulate axon guidance and cell-adhesion genes for precise targeting.

Conclusions:

• The UPR functions not only in protein quality control but also as a sensor of cellular identity.
• This pathway interprets cellular states to direct precise axon wiring in the olfactory system.
• OR identity is converted into ER stress signals that dictate axon targeting specificity.