Project description:Mouse spermatogonial stem cells (SSCs) continuously self-renew on the feeder layers in serum-free culture medium supplemented with glial cell line-derived neurotrophic factor and fibroblast growth factor 2. To identify novel nuclear proteins involved in SSC maintenance, comparative proteomic profiling of nuclear proteins was performed between self-renewing and differentiation-initiated SSCs in culture. The self-renewing SSC cultures were established from C57BL/6 mouse testes. Nuclear fractions from self-renewing SSC cultures treated with ethanol as a vehicle control (spermatogonial stem cells) and differentiation-initiated SSC cultures treated with 0.3 μM retinoic acid for 24 h (spermatogonial progenitor cells) were isolated for proteomic analysis.
Project description:Arid3a, a transcription factor known for its requirement in B-lymphocyte development, has been recently identified as a member of ES cell pluripotency network. Arid3a is moderately expressed in ES cells, and its expression is gradually increased during differentiation. Since Arid3a shows the highest expression in placenta, we hypothesized that Arid3a may play important roles in TE development. We report that Arid3a is a central regulator of both TE-specific and pluripotency-associated gene expression during ES cell differentiation. While dispensable for self-renewal, we observed that knockdown of Arid3a delays differentiation of ES cells. Induction of Arid3a leads ES cells to promote differentiation, specifically towards TE lineage. Moreover, these Arid3a-overexpressing cells maintained in TE culture media are sufficient to generate functional trophoblast stem-like cells, suggesting roles of Arid3a in TE differentiation. By integrative analyses using the chromosomal targets of Arid3a with expression profiling, we revealed the dual roles of Arid3a, as a direct activator of TE-specific genes and a repressor of pluripotency-associated genes. We further revealed the repressive roles of Arid3a are mediated by histone deacetylases (HDACs). Taken together, our results demonstrate that Arid3a is a critical novel regulator in TE lineage specification. Arid3a ChIP was performed using bioChIP-sequencing. Control ChIP-sequencing was performed using BirA cells. HDAC1 ChIP was performed as native antibody ChIP-sequencing.
Project description:A critical problem in biology is understanding how cells choose between self-renewal and differentiation. To generate a comprehensive view of the mechanisms controlling early hematopoietic precursor self-renewal and differentiation, we used systems-based approaches and murine EML multipotential hematopoietic precursor cells as a primary model. EML cells give rise to a mixture of self-renewing Lin-SCA+CD34+ cells and partially differentiated non-renewing Lin-SCA-CD34- cells in a cell autonomous fashion. We identified and validated the HMG box protein TCF7 as a key regulator in this self-renewal/differentiation switch, and it operates in the absence of canonical Wnt signaling. We found that TCF7 is the most downregulated transcription factor when CD34+ cells switch into CD34- cells using RNA-Seq. We subsequently identified the target genes bound by TCF7 using ChIP-Seq. We show that TCF7 binds to Runx1 (Aml1) promoter region, and RUNX1 and TCF7 co-regulate. Gene Set Enrichment Analysis suggests that TCF7 primarily acts as a positive regulator of genes preferentially expressed in CD34+ cells. Consistent with this possibility, knocking-down TCF7 represses many up-regulated genes in Lin-CD34+ cells. Finally a network of up-regulated transcription factors of CD34+ cells which defines the self-renewing state was constructed. These studies in EML cells demonstrate fundamental cell-intrinsic properties of the switch between self-renewal and differentiation, and yield valuable insights for manipulating HSCs and other differentiating systems. Examining the transcription factor binding targets of TCF7 and RUNX1.
Project description:During development, human primordial germ cells (hPGCs) transition through a transcriptional and epigenetic state similar to pre-implantation epiblast cells called naive ground-state pluripotency. Diagnostic transcription factors that define this state include TFAP2C, KLF4, and TFCP2L1, with TFAP2C necessary for both establishment of the naive-like state in hPGC-like cells (hPGCLCs) as well as establishment and self-renewal of naive human embryonic stem cells (hESCs). Here, we show that KLF4 and TFCP2L1 are not required for hPGC specification or establishment of the naive-like state in hPGCLCs. Instead, KLF4 and TFCP2L1 are each required for reversion of primed hESCs to the self-renewing naive ground state. Additionally, TFCP2L1 but not KLF4 function after hPGC specification in the proliferation of the hPGCLC population.
Project description:<p>Acute myeloid leukemia is an aggressive clonal malignancy of the bone marrow that is the direct result of sequential acquisition of mutations in a single lineage of cells. In this study, we investigate a model in which this mutational acquisition occurs serially in long-lived self-renewing hematopoietic stem cells eventually resulting in frank acute myeloid leukemia. Coding mutations in multiple AML patients were identified using exome sequencing followed by sanger sequencing validation. The level of these mutations was then assessed in residual hematopoietic stem cells from each patient using targeted deep sequencing. These population-level estimates of mutant allele burden were then validated in single cell assays targeted to the identified mutations. This allowed for determination of the order of acquisition of the mutations that preceded the development of the leukemia. The results of this study identify pre-leukemic hematopoietic stem cell clones that could contribute to patient relapse and outcome.</p>
Project description:Chromatin accessibility was profiled by ATAC-seq in normal and glioblastoma-derived neural stem (GNS) cells, in self-renewing conditions and in response to differentiation stimulus with bone morphogenic protein (BMP).