RNA editing is abundant and correlates with task performance in a social bumblebee

Area of Science:

• Molecular Biology
• Neuroscience
• Insect Biology

Background:

• Bumblebee workers show significant phenotypic variation despite genetic similarity, hinting at epigenetic regulation.
• Adenosine deaminating RNA (ADAR) enzymes are known to mediate RNA editing, but their role in insects lacking ADAR1 homologs is unclear.

Purpose of the Study:

• To investigate the extent and nature of ADAR-mediated RNA editing in the bumblebee Bombus terrestris.
• To identify genes affected by RNA editing and explore potential links between editing levels and bee behavior.

Main Methods:

• High-throughput sequencing to identify genomic sites of RNA editing.
• Analysis of protein-coding and non-coding transcripts to quantify editing levels.
• Correlation analysis between editing levels and behavioral tasks (brood care, foraging), dominance rank, and juvenile hormone levels.

Main Results:

• A high level of ADAR-mediated RNA editing was detected in Bombus terrestris, with 1.15 million unique genomic sites and 164 recoding sites identified in 100 protein-coding genes.
• Edited genes include those involved in ion channels, transporters, and receptors, potentially impacting brain function and behavior.
• Some RNA editing sites are conserved across diverse species, including insects, cephalopods, and mammals.
• Global RNA editing levels showed a weak correlation with task performance (brood care vs. foraging) but were not influenced by dominance rank or juvenile hormone levels.

Conclusions:

• Bombus terrestris possesses a high capacity for ADAR-mediated RNA editing, even without an ADAR1 homolog.
• RNA editing in bumblebee brains is extensive and affects genes crucial for neural function.
• Behavioral context, such as brood care or foraging, may influence RNA editing levels through short-term regulatory effects.