Transcriptional Interference Gates Monogenic Odorant Receptor Expression in Ants

Area of Science:

• Molecular Biology
• Neuroscience
• Genetics

Background:

• Olfaction is vital for ant communication, with ants possessing an exceptionally large number of odorant receptor (OR) genes organized in genomic arrays.
• The mechanism by which a single functional OR is expressed from these large gene arrays in olfactory sensory neurons remains largely unknown.

Purpose of the Study:

• To elucidate the regulatory mechanisms governing the expression of single functional odorant receptors (ORs) from large gene arrays in ants.
• To investigate the role of non-canonical transcription and long non-coding RNAs in OR gene expression regulation.

Main Methods:

• Analysis of mRNA export and nuclear retention in olfactory sensory neurons.
• Investigation of OR promoter activity, including bidirectional transcription.
• Comparative analysis of regulatory architecture across different insect species.

Main Results:

• Non-canonical readthrough transcription generates non-translated transcripts in the downstream direction.
• OR promoters are bidirectional, producing antisense long non-coding RNAs that suppress upstream gene expression.
• The identified regulatory architecture for OR expression is conserved in both ants and bees.

Conclusions:

• A novel regulatory mechanism involving readthrough transcription and antisense long non-coding RNAs ensures functionally monogenic OR expression from large gene arrays.
• This complex regulatory system is conserved across ants and bees, suggesting a widespread mechanism in insects with expanded OR repertoires.