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Isolation of Peritoneum-derived Mast Cells and Their Functional Characterization with Ca2+-imaging and Degranulation Assays
Published on: July 4, 2018
PU.1 positively regulates GATA-1 expression in mast cells
Clifford M Takemoto1, Stephanie Brandal, Anil G Jegga
1Division of Pediatric Hematology, The Johns Hopkins University, Baltimore, MD 21205, USA. ctakemot@jhmi.edu
Journal of Immunology (Baltimore, Md. : 1950)
|March 23, 2010
Summary
Transcription factor PU.1 activates a unique GATA-1 mRNA isoform in mast cells, distinct from its role in other blood cell types. This finding reveals a novel regulatory pathway essential for mast cell development.
Area of Science:
- Hematopoiesis
- Molecular Biology
- Gene Regulation
Background:
- PU.1 and GATA-1 transcription factors are crucial for mast cell lineage specification.
- PU.1 and GATA-1 exhibit antagonistic functions in myeloid and erythroid lineages.
Purpose of the Study:
- To elucidate the transcriptional network regulating GATA-1 expression in mast cell development.
- To identify a novel GATA-1 mRNA isoform and its regulatory mechanism in mast cells.
Main Methods:
- Isolation and characterization of a variant GATA-1 mRNA isoform in murine mast cells.
- Chromatin immunoprecipitation (ChIP) to assess transcription factor binding in vivo.
- Reporter assays to identify and characterize cis-regulatory elements.
Main Results:
- A variant GATA-1 mRNA isoform (IB) was identified and found to be upregulated during mast cell differentiation.
- PU.1 and GATA-2 were shown to bind to regulatory elements associated with the IB exon in mast cells.
- PU.1 was demonstrated to activate an enhancer element regulating the IB exon.
- PU.1 deficiency abrogated the IB isoform, while its reintroduction restored it and promoted mast cell differentiation.
Conclusions:
- PU.1 positively regulates a specific GATA-1 isoform (IB) in mast cells through a distinct transcriptional pathway.
- This PU.1-driven pathway differs from the antagonistic roles of PU.1 and GATA-1 in erythroid and megakaryocytic lineages.
- The findings establish a transcriptional hierarchy where PU.1, potentially with GATA-2, controls GATA-1 expression for mast cell development.
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