Loss of motoneuron-specific microRNA-218 causes systemic neuromuscular failure [RNA-seq]

We investigated microRNA expression in motoneurons by performing small RNA sequencing of fluorescence-activated cell sorting (FACS)-isolated motoneurons labelled with the Hb9:gfp transgenic reporter and Hb9:gfp negative non-motoneurons including spinal interneurons. We find that one microRNA, microRNA-218, is highly enriched and abundantly expressed in motoneurons. Furthermore, we find that miR-218 is transcribed from alternative, motoneuron-specific alternative promoters embedded within the Slit2 and Slit3 genes by performing RNA sequencing of FACS-isolated motoneurons and a dissected embryonic floor plate cells which served as a control. Next, we performed RNA sequencing of FACS-isolated wild type (WT) motoneurons and motoneurons lacking miR-218 expression (218DKO motoneurons), and find that a large set of genes (named ''TARGET218'' genes) with predicted miR-218 binding sites are de-repressed in the absence of miR-218 expression. Finally, we examine the expression of TARGET218 genes in other neuronal subpopulations by FACS-isolating V1, V2a, and V3 interneurons expressing Cre-inducible fluorescent reporters and performing RNA sequencing. We find that the TARGET218 network of genes is depleted in wild-type motoneurons versus these interneuron types. Additionally, these genes are expressed at similar levels in 218DKO motoneurons compared with interneuron subtypes, suggesting that this genetic network. Overall design: Examination of mRNA expression in spinal progenitor, glial, and neuronal subpopulations.

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Amin ND, Bai G, Klug JR, Bonanomi D, Pankratz MT, Gifford WD, Hinckley CA, Sternfeld MJ, Driscoll SP, Dominguez B, Lee KF, Jin X, Pfaff SL