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A Behavioral Assay for Mechanosensation of MARCM-based Clones in Drosophila melanogaster
Published on: December 30, 2015
MicroRNA mutant turns back the evolutionary clock for fly olfaction
1Biological Sciences, KAIST, 335 Gwanghangno, Yuseong-gu, Daejeon, 305-701, Republic of Korea. waltonjones@kaist.edu
Abstract:
In a recent paper, Cayirlioglu et al. report that the disruption of a specific miRNA, miR-279, which normally acts to inhibit the transcription factor Nerfin-1, uncovers a population of hybrid CO2 neurons in the Drosophila maxillary palp.1 Normally, fruit fly CO2 neurons are found only in the antennae, while mosquito CO2 neurons are found only in the maxillary palps. The hybrid neurons in this miRNA mutant may, thus, recapitulate an evolutionary intermediate unseen since the divergence of these two dipteran lineages over 250 million years ago.
Insights
Disrupting microRNA-279 (miR-279) in Drosophila revealed hybrid carbon dioxide (CO2) neurons in the maxillary palp, potentially showing an ancient evolutionary form.
Area of Science:
- Neuroscience
- Developmental Biology
- Evolutionary Biology
Background:
- Carbon dioxide (CO2) sensing neurons are crucial for host-seeking behavior in insects.
- In Drosophila (fruit flies), CO2 neurons are located in the antennae, while in mosquitoes, they are in the maxillary palps.
- MicroRNAs (miRNAs) are small non-coding RNAs that regulate gene expression, often playing roles in development and evolution.
Purpose of the Study:
- To investigate the role of microRNA-279 (miR-279) in the development and localization of CO2 sensing neurons in Drosophila.
- To explore the potential evolutionary implications of altered CO2 neuron populations.
Main Methods:
- Genetic manipulation to disrupt the function of miR-279 in Drosophila.
- Analysis of CO2 neuron populations and their locations within the Drosophila sensory system.
- Comparison of observed neuronal phenotypes with known distributions in related dipteran species.
Main Results:
- Disruption of miR-279 led to the uncovering of hybrid CO2 neurons in the maxillary palp of Drosophila.
- These hybrid neurons normally reside in the antennae, suggesting a regulatory role for miR-279 in their proper localization.
- The presence of maxillary palp CO2 neurons in a Drosophila mutant mimics the condition found in mosquitoes.
Conclusions:
- miR-279 acts as an inhibitor of Nerfin-1, a transcription factor that likely dictates CO2 neuron identity and location.
- The miR-279 mutant Drosophila may represent an evolutionary intermediate, reflecting a state prior to the divergence of fly and mosquito lineages.
- This finding provides insights into the molecular mechanisms underlying neuronal evolution and diversification in insects.
