RNA interference machinery-mediated gene regulation in mouse adult neural stem cells

Background Neurogenesis in the brain of adult mammals occurs throughout life in two locations: the subventricular zone of the lateral ventricle and the subgranular zone of the dentate gyrus in the hippocampus. RNA interference mechanisms have emerged as critical regulators of neuronal differentiation. However, to date, little is known about its function in adult neurogenesis. Results Here we show that the RNA interference machinery regulates Doublecortin levels and is associated with chromatin in differentiating adult neural progenitors. Deletion of Dicer causes abnormal higher levels of Doublecortin. The microRNA pathway plays an important role in Doublecortin regulation. In particular miRNA-128 overexpression can reduce Doublecortin levels in differentiating adult neural progenitors. Conclusions We conclude that the RNA interference components play an important role, even through chromatin association, in regulating neuron-specific gene expression programs

MOESM2 of RNA interference machinery-mediated gene regulation in mouse adult neural stem cells

Additional file 2: Figure S2. miRNA-128 levels in adult neural progenitors cells. Shown is a Taqman quantitative RT-PCR on undifferentiated (undiff) or differentiating (diff; 4 days after growth factor withdrawal) adult neural progenitor cells. Levels of mature miR-128 were calculated as fold change relative to the housekeeping gene snoRNA55. n = 3, bars represent the mean ± standard error of the mean. Three independent biological samples have been analyzed

MOESM1 of RNA interference machinery-mediated gene regulation in mouse adult neural stem cells

Additional file 1: Figure S1. Dicer deletion in adult neural stem cells. a–b The samples analyzed were adult neural stem cells Dicer flox/flox (f/f) or Dicer −/−. Dicer deletion was obtained by transducing the Dicer f/f cells with HTN-Cre protein. a) Representative picture of PCR genotyping of adult neural stem cells Dicer f/f and Dicer −/−. Efficient Dicer deletion was obtained by transducing the Dicer f/f cells with HTN-Cre protein. Primers-Δ only amplify in case of recombination. b) Quantitative RT-PCR. The cycle threshold numbers are plotted for the indicated genes. Srp14 is a housekeeping gene. The cycle threshold numbers are reciprocally correlated to the amount of template at the start of linear amplification. Nestin, Sox2 and Srp14 expression levels are very similar in both Dicer f/f or Dicer −/− cells. The mean values from 3 independent experiments are shown. Error bars indicate the standard error of the mean

miR-128 regulates neuronal migration, outgrowth and intrinsic excitability via the intellectual disability gene Phf6

miR-128, a brain-enriched microRNA, has been implicated in the control of neurogenesis and synaptogenesis but its potential roles in intervening processes have not been addressed. We show that post-transcriptional mechanisms restrict miR-128 accumulation to post-mitotic neurons during mouse corticogenesis and in adult stem cell niches. Whereas premature miR-128 expression in progenitors for upper layer neurons leads to impaired neuronal migration and inappropriate branching, sponge-mediated inhibition results in overmigration. Within the upper layers, premature miR-128 expression reduces the complexity of dendritic arborization, associated with altered electrophysiological properties. We show that Phf6, a gene mutated in the cognitive disorder Börjeson-Forssman-Lehmann syndrome, is an important regulatory target for miR-128. Restoring PHF6 expression counteracts the deleterious effect of miR-128 on neuronal migration, outgrowth and intrinsic physiological properties. Our results place miR-128 upstream of PHF6 in a pathway vital for cortical lamination as well as for the development of neuronal morphology and intrinsic excitability