Project description:The RNA polymerase II transcriptional Mediator subunit MED12 is broadly implicated in vertebrate brain development, and genetic variation in human MED12 is associated with X-linked intellectual disability and neuropsychiatric disorders. Although prior studies have begun to elaborate the functional contribution of MED12 within key neurodevelopmental pathways, a more complete description of MED12 function in the developing nervous system, including the specific biological networks and cellular processes under its regulatory influence, remains to be established. Herein, we sought to clarify the global contribution of MED12 to neural stem cell (NSC) biology through unbiased transcriptome profiling of mouse embryonic stem (ES) cell-derived NSCs following RNAi-mediated MED12 depletion. A total of 240 genes (177 up, 73 down) were differentially expressed in MED12-knockdown versus control mouse NS-5 (mNS-5) NSCs. Gene set enrichment analysis revealed MED12 to be prominently linked with “cell-to-cell interaction” and “cell cycle” networks, and subsequent functional studies confirmed these associations. Targeted depletion of MED12 led to enhanced NSC adhesion and upregulation of cell adhesion genes, including Syndecan 2 (SDC2). Concomitant depletion of both SDC2 and MED12 reversed enhanced cell adhesion triggered by MED12 knockdown alone, confirming that MED12 negatively regulates NSC cell adhesion by suppressing the expression of cell adhesion molecules. MED12-mediated suppression of NSC adhesion is a dynamically regulated process in vitro, enforced in self-renewing NSCs and alleviated during the course of neuronal differentiation. Accordingly, MED12 depletion enhanced adhesion and prolonged survival of mNS-5 NSCs induced to differentiate on gelatin, effects that were bypassed completely by growth on laminin. On the other hand, MED12 depletion in mNS-5 NSCs led to reduced expression of G1/S phase cell cycle regulators and a concordant G1/S phase cell cycle block without evidence of apoptosis, resulting in a severe proliferation defect. These findings suggest that MED12 contributes to the maintenance of NSC identity through a functionally bipartite role in suppression and activation of gene expression programs dedicated to cell adhesion and G1/S phase cell cycle progression, respectively. MED12 may thus contribute to the regulatory apparatus that controls the balance between NSC self-renewal and differentiation, with important implications for MED12-linked neurodevelopmental disorders.
Project description:Expression profiling following depletion of Mediator Cdk8 module subunits Cdk8, Cyclin C (CycC), Med12 and Med13 72 hours after dsRNA treatment of Drosophila melanogaster S2 cells. Results provide insight into the role of individual Cdk8 module subunits in regulation of transcription. 22 samples. 2 Cdk8 dsRNA, 4 CycC dsRNA, 4 Med12 dsRNA, 4 Med13 dsRNA, 8 control samples including 4 Luciferase (Luc) dsRNA and 4 GFP dsRNA
Project description:Neural stem cells (NSCs) generate neurons and glial cells throughout embryonic and postnatal brain development. The role of s-acylation, a reversible post-translational lipid modification of proteins, in regulating fate and activity of NSCs remains largely unknown. We here used an unbiased screening approach to identify proteins that are s-acylated in mouse NSCs.
Project description:The activation of quiescent neural stem cells (qNSCs) in the dentate gyrus is required for lifelong neurogenesis. However, the mechanisms that promote the exit of neural stem cells (NSCs) from quiescence remain elusive. We demonstrate that the expression of plant homeodomain finger protein 2 (Phf2) activates the exit of postnatal mouse NSC from shallow quiescence. Loss of Phf2 prevents NSC activation and neurogenesis in postnatal 30 (P30) mice but does not decrease the label-retaining NSC pool, indicating that Phf2 is not required for the exit of NSC from quiescence. NSC-specific deletion of Phf2 modestly compromises embryonic mouse NSC proliferation without increasing apoptosis, indicating that Phf2 is crucial for embryonic development. Moreover, human cortical organoids reveal that Phf2 promotes NPC proliferation via a lysine demethylase-independent manner. Mechanistically, Phf2 directly binds to the cohesion complex via Rad21 and regulates the DNA replication in mouse NSC by associating with the cohesion complex releasing protein Wapl activity. Our study identifies the Phf2-cohesin complex mediated DNA replication for neural stem cell activation in a lysine demethylase-independent manner.
Project description:Combinatorial transcription codes generate the myriad of cell types during development, and thus likely provide crucial insights into directed differentiation of stem cells to a specific cell type. The LIM-complex composed of Isl1 and Lhx3 directs the specification of spinal motor neurons (MNs) in embryos. Here, we report that Isl1-Lhx3, a LIMcomplex-mimicking fusion, induces a signature of MN transcriptome and concomitantly suppresses interneuron differentiation programs, thereby serving as a potent and specific inducer of MNs in stem cells. We show that an equimolar ratio of Isl1 and Lhx3 and the LIM-domain of Lhx3 are crucial for generating MNs without upregulating interneuron genes. These led us to design Isl1-Lhx3, which maintains the desirable 1:1 ratio of Isl1 and Lhx3 and the LIM-domain of Lhx3. Isl1-Lhx3 drives MN differentiation with high specificity and efficiency in the spinal cord and embryonic stem cells, bypassing the need for sonic hedgehog. RNA-seq analysis revealed that Isl1-Lhx3 induces the expression of a battery of MN genes that control various functional aspects of MNs, while suppressing key interneuron genes. Our studies uncover a highly efficient method for directed MN generation and MN gene networks. Our results also demonstrate a general strategy of utilizing embryonic transcription complexes for producing specific cell types from stem cells. Examine the RNA expression profiles of inducible motor neurons-embryonic stem cells (iMN-ESCs) with or without Dox treatment, with biological duplicates.
Project description:Expression profiling following depletion of Mediator Cdk8 module subunits Cdk8, Cyclin C (CycC), Med12 and Med13 72 hours after dsRNA treatment of Drosophila melanogaster S2 cells. Results provide insight into the role of individual Cdk8 module subunits in regulation of transcription.
Project description:TAF4 directed immunoprecipitation of the the Pre-initiation complex from mouse embryonic stem cells with or without depletion of TATA-box binding protein (TBP).
Project description:Amyotrophic lateral sclerosis type 6 (ALS6) is a familial subtype of ALS linked to Fused in Sarcoma (FUS) gene mutation. FUS mutations lead to decreased global protein synthesis, but the mechanism that drives this has not been established. Here, we used ALS6 patient-derived induced pluripotent stem cells (hIPSCs) to study the effect of the ALS6 FUSR521H mutation on the translation machinery in motor neurons (MNs). We find, in agreement with findings of others, that protein synthesis is decreased in ALS6 MNs. Furthermore, ALS6 MNs are more sensitive to oxidative stress and display reduced expression of TGF-β and mTORC gene pathways when stressed. Finally, we show that IFNγ treatment reduces apoptosis of ALS6 MNs exposed to oxidative stress and partially restores the translation rates in ALS6 MNs. Overall, these findings suggest that a functional IFNγ response is important for FUS-mediated protein synthesis, possibly by FUS nuclear translocation in ALS6.
Project description:We describe a so far uncharacterized, embryonic and self-renewing Neural Plate Border Stem Cell (NBSC) population with the capacity to differentiate into central nervous and neural crest lineages. NBSCs can be obtained by neural transcription factor-mediated reprogramming (BRN2, SOX2, KLF4, and ZIC3) of human adult dermal fibroblasts and peripheral blood cells (induced Neural Plate Border Stem Cells, iNBSCs) or by directed differentiation from human induced pluripotent stem cells (NBSCs). Moreover, human (i)NBSCs share molecular and functional features with primary Neural Plate Border Stem Cells (pNBSCs) isolated from neural folds of E8.5 mouse embryos. Here we provide single cell RNA-sequencing data of neural tissue derived from two E8.5 mouse embryos. After manual isolation and enzymatic separation E8.5 neural tissue was single cell sorted and RNA sequencing was performed following the Smart-seq2 protocol. In sum, cultured pNBSCs and E8.5 neural tube cells share a similar regional identity and expression signature suggesting that pNBSCs might correspond to an endogenous progenitor in this area of the developing brain.