ABUNDANT EXPRESSION OF TRANSCRIPTION FACTOR GATA-2 IN PROLIFERATING BUT NOT IN DIFFERENTIATED MAST-CELLS IN TISSUES OF MICE - DEMONSTRATIONBY IN-SITU HYBRIDIZATION

Although GATA-binding transcription factors (GATA-1 and GATA-2) are st rongly expressed in cultured mast cells (CMCs), their expression in ma st cells within tissues has not been reported. We examined the express ion of GATA-1 and GATA-2 in skin tissues of mice using Northern blot a nalysis and in situ hybridization. mRNA for GATA-2 but not for GATA-1 was expressed in skin mast cells of WB-+/+ embryos between days 15 and 17 postcoitum (pc). The expression was downregulated on and after day 18 pc. Skin mast cells did not express GATA-2 after birth either. Whe n the number of skin mast cells was compared with the number of GATA-2 mRNA-expressing cells, GATA-2 mRNA appeared to be expressed by mast c ells only when the number was increasing. When the mRNA expression of high-affinity IgE receptor P-subunit and mast cell carboxypeptidase A was used as differentiation markers, the expression of these mRNAs con tinued even after the downregulation of GATA-2 expression. To clarify the relationship of the proliferation and GATA-2 expression, prolifera ting CMCs derived from WBB6F(1)-+/+ mice were transplanted into the pe ritoneal cavity of mast cell-deficient WBB6F(1)-W/W-v mice. The CMCs s topped bath the proliferation and GATA-2 expression after the transpla ntation, suggesting the association of these two parameters in mast ce lls within tissues of mice. (C) 1996 by The American Society of Hemato logy.