A multifunctional locus controls motor neuron differentiation through short and long noncoding RNAs

The transition from dividing progenitors to postmitotic motor neurons (MNs) is orchestrated by a series of events, which are mainly studied at the transcriptional level by analyzing the activity of specific programming transcription factors. Here, we identify a post‐transcriptional role of a MN‐specific transcriptional unit (MN2) harboring a lncRNA (lncMN2‐203) and two miRNAs (miR‐325‐3p and miR‐384‐5p) in this transition. Through the use of in vitro mESC differentiation and single‐cell sequencing of CRISPR/Cas9 mutants, we demonstrate that lncMN2‐203 affects MN differentiation by sponging miR‐466i‐5p and upregulating its targets, including several factors involved in neuronal differentiation and function. In parallel, miR‐325‐3p and miR‐384‐5p, co‐transcribed with lncMN2‐203, act by repressing proliferation‐related factors. These findings indicate the functional relevance of the MN2 locus and exemplify additional layers of specificity regulation in MN differentiation.