Promotor elements governing the clustered expression pattern of odorant receptor genes

Area of Science:

• Genetics
• Neuroscience
• Molecular Biology

Background:

• Odorant receptor (OR) genes are crucial for smell perception.
• The mOR262 gene family exhibits a restricted expression pattern in olfactory sensory neurons (OSNs).
• Conserved DNA elements upstream of OR genes are hypothesized to regulate their unique expression patterns.

Purpose of the Study:

• To investigate the role of upstream DNA elements in the specific expression of mOR262-12.
• To determine if these elements govern the segregation of OSNs in the nasal turbinates.
• To analyze the axonal convergence of OSNs expressing the transgene and endogenous genes.

Main Methods:

• Generation of mouse lines carrying a transgene with the mOR262-12 coding sequence and upstream region.
• Analysis of transgene expression patterns in olfactory sensory neurons.
• Assessment of axonal projection patterns of transgene-expressing OSNs.

Main Results:

• Transgene expression was largely restricted to the central patch of OSNs, mirroring endogenous mOR262 expression.
• Axons of transgene-expressing OSNs showed co-convergence with endogenous OSN axons.
• One mouse line exhibited ectopic transgene expression in OSNs outside the central patch.
• The transgene demonstrated mutually exclusive and monoallelic expression.

Conclusions:

• Conserved upstream DNA elements are critical for controlling the specific expression pattern of mOR262 family genes.
• These elements play a significant role in the spatial segregation of olfactory sensory neurons.
• The findings provide insights into the molecular mechanisms governing olfactory receptor gene regulation.