Image: Overview of project techniques (left to right): Two electrode voltage clamp to characterise novel receptors, Confocal and expansion microscopy to localise receptors, animal tracking and behavioural experiments to understand the role of receptors in vivo.
Characterising newly discovered neurotransmitter receptors
Supervisor: Dr Iris Hardege
Co-supervisor: Professor Howard Baylis
Traditionally we believe that the ability to perform complex behaviour arises as the size of the brain increases. However, animals with anatomically small brains, like the nematode C. elegans, are capable of complex behaviours such as learning and maze navigation. This raises the question; how do these small networks generate behavioural complexity and are these mechanisms conserved throughout evolution?
Despite having just 302 neurons the nematode genome encodes over 100 genes for fast acting ligand gated ion channels (LGICs) which in mammals includes the fast neurotransmitter receptors nAChR and GABAARs. As well as expressing classical LGICs, worms also express many atypical receptors including inhibitory and excitatory receptors for monoamines including dopamine and serotonin. Recently we discovered a new family of excitatory LGICs that are gated by trace amines and appear to be expressed in neurons that control feeding behaviours (unpublished). The aim of this project it to characterise the function of these and related receptors in detail.
Type of work
1. You will express these novel LGICs in Xenopus oocytes and use Two Electrode Voltage Clamp (TEVC) electrophysiology to characterise the functional properties of the receptors.
2. You will explore the expression of these novel receptors at the cellular and subcellular level using confocal miscopy. To do this, you will use the neuron identification strain called NeuroPAL which allows you to identify individual neurons, next, you will characterise the subcellular expression pattern using endogenously tagged receptors generated by CRISPR knock in.
3. You will explore the behavioural role of these receptors by designing and performing behavioural assays.
Importance of area of research concerned
This research will uncover the function of new types of fast acting ion channel receptors that have not been studied before in any species. Not only will this work help us to better understand information flow through the nervous system of this key model organism, it could also open the door to many further areas of research, including searching for similar receptors in other species, or the development of novel anti-parasitic compounds.
References
Iris Hardege, J Morud, A Courtney, WR Schafer. A Novel and Functionally Diverse Class of Acetylcholine-gated Ion Channels. Journal of Neuroscience (2023) DOI: 10.1523/JNEUROSCI.1516-22.2022
I Hardege, et al. Neuronally Produced Betaine Acts via a Ligand Gated Ion Channel to Control Behavioural States. PNAS (2022) https://doi.org/10.1073/pnas.2201783119