GATA-1 is required for expression of FcεRI on mast cells:: analysis of mast cells derived from GATA-1 knockdown mouse bone marrow

The high-affinity receptor for IgE (Fc epsilon RI) that is expressed on the surface of mast cells plays an important role in antigen/IgE-mediated allergic reactions. We have previously found that critical elements in the promoter of the Fc epsilon RI alpha- and beta-chain genes are recognized by the transcription factor GATA-1 in electrophoretic mobility shift assays coupled with a transient expression system for the alpha- and beta-chain promoters. To confirm that GATA-1 is involved in the expression of Fc epsilon RI definitively, we generated bone marrow-derived mast cells from GATA-1 knockdown (KD) heterozygous mice. FACS analysis showed that the frequency of Fc epsilon RI-positive cells was significantly decreased in mast cells derived from bone marrow of GATA-1 KD mice. Reverse transcription-PCR analysis showed that the level of transcripts not only for GATA-1 but also for both the alpha- and beta-chains was significantly lower in KD mast cells, whereas that of the Fc epsilon RI gamma-chain was not affected. Degranulation caused by cross-linking of Fc epsilon RI on mast cells prepared from KD mice was markedly repressed in comparison with that of wild-type mast cells. We concluded that the transcription factor GATA-1 positively regulates Fc epsilon RI alpha- and beta-chain expression and therefore is involved in mast cell development.