| 1. |
- May, Gillian, et al.
(författare)
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Dynamic Analysis of Gene Expression and Genome-wide Transcription Factor Binding during Lineage Specification of Multipotent Progenitors
- 2013
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Ingår i: Cell Stem Cell. - : Elsevier BV. - 1934-5909. ; 13:6, s. 754-768
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Tidskriftsartikel (refereegranskat)abstract
- We used the paradigmatic GATA-PU.1 axis to explore, at the systems level, dynamic relationships between transcription factor (TF) binding and global gene expression programs as multipotent cells differentiate. We combined global ChIP-seq of GATA1, GATA2, and PU.1 with expression profiling during differentiation to erythroid and neutrophil lineages. Our analysis reveals (1) differential complexity of sequence motifs bound by GATA1, GATA2, and PU.1; (2) the scope and interplay of GATA1 and GATA2 programs within, and during transitions between, different cell compartments, and the extent of their hard-wiring by DNA motifs; (3) the potential to predict gene expression trajectories based on global associations between TF-binding data and target gene expression; and (4) how dynamic modeling of DNA-binding and gene expression data can be used to infer regulatory logic of TF circuitry. This rubric exemplifies the utility of this cross-platform resource for deconvoluting the complexity of transcriptional programs controlling stem/progenitor cell fate in hematopoiesis.
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| 2. |
- Billing, Matilda, et al.
(författare)
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A network including TGFβ/Smad4, Gata2 and p57 regulates proliferation of mouse hematopoietic progenitor cells.
- 2016
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Ingår i: Experimental Hematology. - : Elsevier BV. - 1873-2399 .- 0301-472X. ; 44:5, s. 399-409
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Tidskriftsartikel (refereegranskat)abstract
- Transforming growth factor-β (TGFβ) is a potent inhibitor of hematopoietic stem and progenitor cell proliferation. However, the precise mechanism for this effect is unknown. Here, we have identified the transcription factor Gata2, previously described as an important regulator of hematopoietic stem cell (HSC) function, as an early and direct target gene for TGFβ-induced Smad signaling in hematopoietic progenitor cells. We also report that Gata2 is involved in mediating a significant part of the TGFβ response in primitive hematopoietic cells. Interestingly, the cell cycle regulator and TGFβ signaling effector molecule p57 was found to be upregulated as a secondary response to TGFβ. We observed Gata2 binding upstream of the p57 genomic locus, and importantly loss of Gata2 abolished TGFβ-stimulated induction of p57 as well as the resulting growth arrest of hematopoietic progenitors. Our results connect key molecules involved in HSC self-renewal and reveal a functionally relevant network regulating proliferation of primitive hematopoietic cells.
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| 3. |
- Pina, Cristina, et al.
(författare)
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Inferring rules of lineage commitment in haematopoiesis
- 2012
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Ingår i: Nature Cell Biology. - : Springer Science and Business Media LLC. - 1465-7392 .- 1476-4679. ; 14:3, s. 287-287
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Tidskriftsartikel (refereegranskat)abstract
- How the molecular programs of differentiated cells develop as cells transit from multipotency through lineage commitment remains unexplored. This reflects the inability to access cells undergoing commitment or located in the immediate vicinity of commitment boundaries. It remains unclear whether commitment constitutes a gradual process, or else represents a discrete transition. Analyses of in vitro self-renewing multipotent systems have revealed cellular heterogeneity with individual cells transiently exhibiting distinct biases for lineage commitment(1-6). Such systems can be used to molecularly interrogate early stages of lineage affiliation and infer rules of lineage commitment. In haematopoiesis, population-based studies have indicated that lineage choice is governed by global transcriptional noise, with self-renewing multipotent cells reversibly activating transcriptome-wide lineage-affiliated programs(7). We examine this hypothesis through functional and molecular analysis of individual blood cells captured from self-renewal cultures, during cytokine-driven differentiation and from primary stem and progenitor bone marrow compartments. We show dissociation between self-renewal potential and transcriptome-wide activation of lineage programs, and instead suggest that multipotent cells experience independent activation of individual regulators resulting in a low probability of transition to the committed state.
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| 4. |
- Tipping, Alex J., et al.
(författare)
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High GATA-2 expression inhibits human hematopoietic stem and progenitor cell function by effects on cell cycle
- 2009
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Ingår i: Blood. - : American Society of Hematology. - 1528-0020 .- 0006-4971. ; 113:12, s. 2661-2672
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Tidskriftsartikel (refereegranskat)abstract
- Evidence suggests the transcription factor GATA-2 is a critical regulator of murine hematopoietic stem cells. Here, we explore the relation between GATA-2 and cell proliferation and show that inducing GATA-2 increases quiescence (G(0) residency) of murine and human hematopoietic cells. In human cord blood, quiescent fractions (CD34(+)CD38(-)Hoechst(lo)Pyronin Y-lo) express more GATA-2 than cycling counterparts. Enforcing GATA-2 expression increased quiescence of cord blood cells, reducing proliferation and performance in long-term culture-initiating cell and colony-forming cell (CFC) assays. Gene expression analysis places GATA-2 upstream of the quiescence regulator MEF, but enforcing MEF expression does not prevent GATA-2 conferred quiescence, suggesting additional regulators are involved. Although known quiescence regulators p21(CIP1) and p27(KIP1) do not appear to be responsible, enforcing GATA-2 reduced expression of regulators of cell cycle such as CCND3, CDK4, and CDK6. Enforcing GATA-2 inhibited human hematopoiesis in vivo: cells with highest exogenous expression (GATA-2(hi)) failed to contribute to hematopoiesis in nonobese diabetic-severe combined immunodeficient (NOD-SCID) mice, whereas GATA-2(lo) cells contributed with delayed kinetics and low efficiency, with reduced expression of Ki-67. Thus, GATA-2 activity inhibits cell cycle in vitro and in vivo, highlighting GATA-2 as a molecular entry point into the transcriptional program regulating quiescence in human hematopoietic stem and progenitor cells. (Blood. 2009;113:2661-2672)
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