Transcriptome to Phenotype Mapping of midbrain dopaminergic neurons

The electrical phenotype of neurons is determined by the joint action of multiple voltage-gated, calcium-gated and ligand-gated ion channels. Understanding the emergence of a given electrical phenotype, and its stability during the long life of neurons in the face of internal and external perturbations, requires to develop systems-level approaches considering the ion channels underlying neuronal activity as an organized ensemble and not as isolated entities. Over the past few years, we developed such an approach by combining electrophysiological recordings and single-neuron microfluidic quantitative PCR, in order to obtain in the same neurons a precise quantification of the variations of electrical phenotype and of ion channel expression levels. We tackle this question on substantia nigra pars compacta dopaminergic neurons, which have the specificity of generating a pacemaker pattern of activity observed in vivo and in vitro. This particularity allows us to limit our analysis to intrinsic conductances (voltage-gated and calcium-gated ion channels) and their link with dopaminergic neuron intrinsic activity.

The Master 2 project will pursue this work, aiming at extending the transcriptome to phenotype characterization of dopaminergic neurons already started. The project will involve to characterize the variations of eletrical phenotype in ion channel KO mice, and to harvest mRNAs from the same neurons to define the changes in expression of ion channels. The intern will be in charge of the electrophysiological recordings (patch-clamp) as well as the harvesting of mRNAs by cytoplasm aspiration, mRNA quantification being performed by an external sub-contracted facility. Data analysis will be done in the lab using multi-variate analysis.

Methods: patch-clamp on acute midbrain slices, single-cell quantitative PCR, multi-variate analysis.

Contact : jean-marc.goaillard@univ-amu.fr Tel : 04 91 69 89 54

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