Abstract
The ability to sense the environment is essential for animal survival. Insects are easily affected by different environmental changes, so it is critical for them to detect and distinguish various sensory inputs. The Drosophila melanogaster Ionotropic Receptor 25a (IR25a), an iGluR-related receptor, is widely expressed. Antennal expression of IR25a is involved in many sensory behaviors, including thermal sensing, hygrosensing and chemical sensing. It is also known that IR25a has four different isoforms, but how they work to distinguish sensory inputs is largely unknown. Here we generated Ir25a isoform specific knockout flies by using CRISPR/Cas9. Our immunohistochemistry showed that only the C isoform is expressed in antennae, suggesting that the C isoform is involved in chemical sensing, thermal sensing and hygrosensing. Our electrophysiology recording from the antennal coeloconic sensilla and from the arista of isoform-specific Ir25a mutants further confirmed that the C isoform is involved in chemical sensing and thermal sensing. Our work shows that the same isoform of Ir25a mediates chemical sensing, thermal sensing and hygrosensing. These data suggest that the same IR25a protein isoform combines with different co-factors to mediate different sensory modalities and leaves open the functions of the other IR25a isoforms.