Summary
Linda B. Buck's review revisits the "one receptor-one neuron" rule of olfactory coding, presenting evidence that while a single olfactory sensory neuron (OSN) typically expresses only one odorant receptor (OR) gene, this rule is not absolute and exhibits nuanced exceptions. The review synthesizes findings that demonstrate the intricate mechanisms governing OR gene choice during OSN development, including the roles of epigenetic regulation, stochastic expression, and cellular signaling pathways. It highlights how this precise, yet flexible, expression pattern allows for the combinatorial coding of a vast olfactory landscape.
Readers of this review gain a detailed understanding of the molecular basis for olfactory specificity, appreciating the complex interplay of genetic and cellular factors that ensure each OSN can detect and signal a distinct set of odors. The revisited rule emphasizes the refined complexity of the olfactory system, moving beyond a simple one-to-one mapping to a more sophisticated combinatorial system.
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Key concepts
- Olfactory Sensory Neuron (OSN) — A nerve cell in the olfactory epithelium responsible for detecting odor molecules and transmitting signals to the brain.
- Odorant Receptor (OR) Gene — A gene that encodes a protein responsible for binding to specific odorant molecules, initiating the olfactory signal.
- One Receptor-One Neuron Rule — The principle stating that each olfactory sensory neuron expresses only a single type of odorant receptor.
- Epigenetic Regulation — Heritable changes in gene expression that occur without altering the underlying DNA sequence, influencing OR gene choice.
- Stochastic Expression — The random nature of gene expression, contributing to the probabilistic selection of a single OR gene by an OSN.