Subcellular sequencing of single neurons reveals the dendritic transcriptome of GABAergic interneurons

Although significant efforts have allowed the identification of mRNAs in the processes of excitatory neurons, it is still unclear whether inhibitory neurons also localize a large population of mRNAs. In addition, the variability in the mRNA population within and between cells is not known. Here we developed a method for the transcriptomic characterization of a single neuron9s subcellular compartments, combining laser capture micro dissection with scRNAseq. We separately profile the dendritic and somatic transcriptomes of individual rat hippocampal neurons and investigate the relation in mRNA abundances between the soma and dendrites of single glutamatergic and GABAergic neurons. We found that, like their excitatory counterparts, interneurons contain a rich repertoire of ~4000 mRNAs. Finally, using cell-type specific metabolic labelling of isolated neurites, we demonstrated that the processes not only of Glutamatergic but also of GABAergic neurons are capable of local translation, suggesting mRNA localization and local translation is a general property of neurons.