MicroRNA-independent functions of DGCR8 are essential for neocortical development and TBR1 expression

EMBO Rep. 2017 Apr;18(4):603-618. doi: 10.15252/embr.201642800. Epub 2017 Feb 23.


Recent evidence indicates that the miRNA biogenesis factors DROSHA, DGCR8, and DICER exert non-overlapping functions, and have also roles in miRNA-independent regulatory mechanisms. However, it is currently unknown whether miRNA-independent functions of DGCR8 play any role in the maintenance of neuronal progenitors and during corticogenesis. Here, by phenotypic comparison of cortices from conditional Dgcr8 and Dicer knockout mice, we show that Dgcr8 deletion, in contrast to Dicer depletion, leads to premature differentiation of neural progenitor cells and overproduction of TBR1-positive neurons. Remarkably, depletion of miRNAs upon DCGR8 loss is reduced compared to DICER loss, indicating that these phenotypic differences are mediated by miRNA-independent functions of DGCR8. We show that Dgcr8 mutations induce an earlier and stronger phenotype in the developing nervous system compared to Dicer mutants and that miRNA-independent functions of DGCR8 are critical for corticogenesis. Finally, our data also suggest that the Microprocessor complex, with DROSHA and DGCR8 as core components, directly regulates the Tbr1 transcript, containing evolutionarily conserved hairpins that resemble miRNA precursors, independently of miRNAs.

Keywords: Dgcr8; Tbr1; microRNAs; murine corticogenesis; neurogenesis.

MeSH terms

  • Animals
  • Apoptosis / genetics
  • Basic Helix-Loop-Helix Transcription Factors
  • Cell Line
  • Cell Proliferation
  • DNA-Binding Proteins / genetics*
  • DNA-Binding Proteins / metabolism
  • Gene Deletion
  • Gene Expression Regulation, Developmental*
  • Homeodomain Proteins / metabolism
  • Mice
  • Mice, Knockout
  • Mice, Transgenic
  • MicroRNAs / genetics*
  • Neocortex / embryology*
  • Neocortex / metabolism*
  • Neocortex / pathology
  • Nerve Tissue Proteins
  • Neural Stem Cells / cytology
  • Neural Stem Cells / metabolism
  • Neurogenesis / genetics
  • Neurons / metabolism
  • RNA Interference
  • RNA-Binding Proteins / genetics*
  • RNA-Binding Proteins / metabolism
  • T-Box Domain Proteins
  • Transcription Factors / metabolism


  • Basic Helix-Loop-Helix Transcription Factors
  • DNA-Binding Proteins
  • Dgcr8 protein, mouse
  • Homeodomain Proteins
  • MicroRNAs
  • Nerve Tissue Proteins
  • Neurog2 protein, mouse
  • RNA-Binding Proteins
  • T-Box Domain Proteins
  • Tbr1 protein, mouse
  • Transcription Factors
  • empty spiracles homeobox proteins