You will be shown an abstract from a biomedical research paper. Given this abstract, your task is to extract all unique entities of the following types: ["RNA", "CellLine", "Protein", "DNA", "CellType"].

Please return the output as a JSON object of the format: {"DNA" : ["TAL1", ...], "RNA": ["mRNAs", ...], "CellLine": ["T cells", ...], "CellType": ["monocytes", ...], "Protein": ["IL-2", ...]}. The keys should be entity types and values should be lists of extracted entities belonging to the corresponding type. If you cannot find entities belonging to a specific type, the value should be [].

Only output the JSON object and do not include any additional text.

Abstract:

Cell cycle-dependent initiation and lineage-dependent abrogation of GATA-1 expression in pure differentiating hematopoietic progenitors. The programmed activation / repression of transcription factors in early hematopoietic differentiation has not yet been explored. The DNA-binding protein GATA-1 is required for normal erythroid development and regulates erythroid-expressed genes in maturing erythroblasts. We analyzed GATA-1 expression in early human adult hematopoiesis by using an in vitro system in which " pure " early hematopoietic progenitors are induced to gradual and synchronized differentiation selectively along the erythroid or granulocyte-macrophage pathway by differential treatment with hematopoietic growth factors. The GATA-1 gene, though virtually silent in quiescent progenitors, is activated after entrance into the cell cycle upon stimulation with hematopoietic growth factors. Subsequently, increasing expression along the erythroid pathway contrasts with an abrupt downregulation in the granulocyte-macrophage lineage. These results suggest a microenvironment-directed, two-step model for GATA-1 expression in differentiating hematopoietic progenitors that involves (i) cycle-dependent initiation and (ii) lineage-dependent maintenance or suppression. Hypothetically, on / off switches of lineage-restricted transactivators may underlie the binary fate decisions of hematopoietic progenitors.
{"CellLine": [], "CellType": ["differentiating hematopoietic progenitors", "early hematopoietic progenitors", "granulocyte - macrophage lineage", "pure differentiating hematopoietic progenitors", "quiescent progenitors", "hematopoietic progenitors", "maturing erythroblasts"], "DNA": ["erythroid - expressed genes", "GATA - 1 gene"], "Protein": ["DNA - binding protein", "lineage - restricted transactivators", "GATA - 1", "The DNA - binding protein GATA - 1", "transcription factors"], "RNA": []}