GATA transcription factors (GATA-1-6) regulate mammalian development. GATA-2 is important for hematopoietic stem (HSC) and multipotent progenitor cell differentiation/survival. GATA-1 and GATA-2 occupy a small subset of the binding motifs in cells and can occupy the same chromatin region at distinct developmental times, but with different functional outputs. The following Aims will analyze mechanisms that regulate GATA-2 transcription, how changes in GATA-2 levels affect hematopoiesis, and mechanisms underlying GATA factor chromatin occupancy. 1. To analyze the mechanism of the GATA switch at chromatin sites during hematopoiesis. GATA-2 has a short half-life (~1 h) and is stabilized by treatment of cells with proteasome inhibitors. When GATA-2 is stabilized, GATA-1-mediated displacement of GATA-2 from chromatin is attenuated. We will test the hypothesis that ubiquitination destabilizes GATA-2, and instability is required for GATA-1 to access GATA-2-bound chromatin sites. We will also test whether an excess of GATA-1 versus GATA-2 is required for the switch. 2. To dissect the mechanism of GATA-2 transcription in vivo. GATA-2 occupies the -2.8 kb and -1.8 kb regions of the active GATA-2 locus, whereas GATA-1 occupies predominantly the -2.8 kb region of the inactive locus. GATA-1 binding displaces GATA-2 from both regions and is coupled to repression. We generated targeted deletions of the -2.8 kb and -1.8 kb regions to test the hypothesis that these regions confer activation and the -2.8 kb region mediates repression. We will determine if the deletions affect assembly of the histone modification pattern, RNA polymerase II recruitment, and transcription. 3. To test whether GATA-1 and GATA-2 have differentiation stage-specific target genes. We propose that intrinsic features of the motifs, nearby c/s-elements, protein-protein interactions and chromatin structure constitute a GATA Recognition Code (GRC) that specifies occupancy. Elucidating the GRC requires analysis of occupancy at multiple target genes. GATA factor occupancy will be defined by quantitative chromatin immunoprecipitation (ChIP) and ChIP coupled with genomic microarrays. The studies will reveal how GATA switches regulate GATA-2 transcription, how GATA-1 and GATA-2 select DMA motifs, and insights of broad relevance to diverse developmental processes. ? ?
| Katsumura, Koichi R; Mehta, Charu; Hewitt, Kyle J et al. (2018) Human leukemia mutations corrupt but do not abrogate GATA-2 function. Proc Natl Acad Sci U S A 115:E10109-E10118 |
| Lu, Zhanping; Hong, Courtney C; Kong, Guangyao et al. (2018) Polycomb Group Protein YY1 Is an Essential Regulator of Hematopoietic Stem Cell Quiescence. Cell Rep 22:1545-1559 |
| Bresnick, Emery H; Hewitt, Kyle J; Mehta, Charu et al. (2018) Mechanisms of erythrocyte development and regeneration: implications for regenerative medicine and beyond. Development 145: |
| McIver, Skye C; Hewitt, Kyle J; Gao, Xin et al. (2018) Dissecting Regulatory Mechanisms Using Mouse Fetal Liver-Derived Erythroid Cells. Methods Mol Biol 1698:67-89 |
| Mehta, Charu; Johnson, Kirby D; Gao, Xin et al. (2017) Integrating Enhancer Mechanisms to Establish a Hierarchical Blood Development Program. Cell Rep 20:2966-2979 |
| Hewitt, Kyle J; Katsumura, Koichi R; Matson, Daniel R et al. (2017) GATA Factor-Regulated Samd14 Enhancer Confers Red Blood Cell Regeneration and Survival in Severe Anemia. Dev Cell 42:213-225.e4 |
| Zhang, Jingfang; Kong, Guangyao; Rajagopalan, Adhithi et al. (2017) p53-/- synergizes with enhanced NrasG12D signaling to transform megakaryocyte-erythroid progenitors in acute myeloid leukemia. Blood 129:358-370 |
| Katsumura, Koichi R; Bresnick, Emery H; GATA Factor Mechanisms Group (2017) The GATA factor revolution in hematology. Blood 129:2092-2102 |
| Katsumura, Koichi R; Ong, Irene M; DeVilbiss, Andrew W et al. (2016) GATA Factor-Dependent Positive-Feedback Circuit in Acute Myeloid Leukemia Cells. Cell Rep 16:2428-41 |
| Gao, Xin; Wu, Tongyu; Johnson, Kirby D et al. (2016) GATA Factor-G-Protein-Coupled Receptor Circuit Suppresses Hematopoiesis. Stem Cell Reports 6:368-82 |
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