Project description:Cbx3 (HP1γ) that is a member of the heterochromatin protein 1 family play important roles in development and differentiation. To determine the regulatroy mechanisms of Cbx3 during neural differentiation from ESCs to NPCs, we performed RNA-seq analysis of ESCs or ESC-derived NPCs depleted for Cbx3 or Cbx3-assocatied Mediator subunit Med26.
Project description:<p>During development of the human brain, multiple cell types with diverse regional identities are generated. Here we report a system to generate early human brain forebrain and mid/hindbrain cell types from human embryonic stem cells (hESCs), and infer and experimentally confirm a lineage tree for the generation of these types based on single-cell RNA-Seq analysis. We engineered <i>SOX2<sup>Cit/+</sup></i> and <i>DCX<sup>Cit/Y</sup></i> hESC lines to target progenitors and neurons throughout neural differentiation for single-cell transcriptomic profiling, then identified discrete cell types consisting of both rostral (cortical) and caudal (mid/hindbrain) identities. Direct comparison of the cell types were made to primary tissues using gene expression atlases and fetal human brain single-cell gene expression data, and this established that the cell types resembled early human brain cell types, including preplate cells. From the single-cell transcriptomic data a Bayesian algorithm generated a unified lineage tree, and predicted novel regulatory transcription factors. The lineage tree highlighted a prominent bifurcation between cortical and mid/hindbrain cell types, confirmed by clonal analysis experiments. We demonstrated that cell types from either branch could preferentially be generated by manipulation of the canonical Wnt/beta-catenin pathway. In summary, we present an experimentally validated lineage tree that encompasses multiple brain regions, and our work sheds light on the molecular regulation of region-specific neural lineages during human brain development.</p>
Project description:Cbx3 (HP1γ) that is a member of the heterochromatin protein 1 familiy enriched in gene bodies of pluripotent ESCs but promoters of differentiated pre-iPSCs. To determine whether Cbx3 becomes enriched at promoters to influence gene regulation during differentiation, we converted ESCs to NPCs in monolayer culuture and performed genomewide ChIP-seq of Cbx3. Our results shows that Cbx3 enriches at the promoters of genes upon differentiation of ESCs to NPCs and stablizes the binding of Mediator subunit Med26 to pre-initiation complex (PIC) in NPCs.
Project description:<p>In this study, we describe a systematic analysis of pseudogene 'transcription' from an RNA-Seq resource of 293 samples, from 13 cancer and normal tissue types. We observed a highly prevalent, genome-wide expression of pseudogenes that could be categorized as universally expressed or lineage- and/or cancer-specific. We also explored disease subtype specificity and functions of selected expressed pseudogenes. We provide evidence that transcribed pseudogenes are a significant contributor to the transcriptional landscape of cells and are positioned to play significant roles in cellular differentiation and cancer progression. Our work provides a transcriptome resource that enables high-throughput analyses of pseudogene expression.</p>
Project description:Recent reports have proposed a new paradigm for obtaining mature somatic cell types from fibroblasts without going through a pluripotent state, by briefly expressing canonical iPSC reprogramming factors Oct4, Sox2, Klf4 and c-Myc (abbreviated as OSKM), in cells expanded in lineage differentiation promoting conditions. Here we apply genetic lineage tracing for endogenous Nanog, Oct4 and X chromosome reactivation during OSKM induced trans-differentiation, as these molecular events mark final stages for acquisition of induced pluripotency. Remarkably, the vast majority of reprogrammed cardiomyocytes or neural stem cells derived from mouse fibroblasts via OSKM mediated trans-differentiation were attained after transient acquisition of pluripotency, and followed by rapid differentiation. Our findings underscore a molecular and functional coupling between inducing pluripotency and obtaining “trans-differentiated” somatic cells via OSKM induction, and have implications on defining molecular trajectories assumed during different cell reprogramming methods. poly RNA-Seq and Chromatin accesibility (ATAC-seq) were measured during conversion of mouse embryonic fibroblasts to neural stem cells using OSKM trans-differentiation method, as well as in mouse emrbyonic fibroblasts, iPSCs and mouse ESCs.
Project description:Recent reports have proposed a new paradigm for obtaining mature somatic cell types from fibroblasts without going through a pluripotent state, by briefly expressing canonical iPSC reprogramming factors Oct4, Sox2, Klf4 and c-Myc (abbreviated as OSKM), in cells expanded in lineage differentiation promoting conditions. Here we apply genetic lineage tracing for endogenous Nanog, Oct4 and X chromosome reactivation during OSKM induced trans-differentiation, as these molecular events mark final stages for acquisition of induced pluripotency. Remarkably, the vast majority of reprogrammed cardiomyocytes or neural stem cells derived from mouse fibroblasts via OSKM mediated trans-differentiation were attained after transient acquisition of pluripotency, and followed by rapid differentiation. Our findings underscore a molecular and functional coupling between inducing pluripotency and obtaining “trans-differentiated” somatic cells via OSKM induction, and have implications on defining molecular trajectories assumed during different cell reprogramming methods. poly RNA-Seq was measured before, during and after conversion of mouse embryonic fibroblasts to neural stem cells using OSKM trans-differentiation method.