Roles of MITF for development of mast cells in mice: effects on both precursors and tissue environments

Abstract

Abstract The mutant tg/tg mice, which do not express mi transcription factor (MITF), lack mast cells in most tissues. Since MITF is expressed in both mast cells and tissues where mast cells develop, there is a possibility that the tg/tg mice may show abnormalities in both mast cell precursors and tissue environments. We examined this possibility by bone marrow and skin transplantation. When bone marrow cells of tg/tg mice were transplanted to W/Wv mice that possess normal tissue environment, mast cells did not develop in all tissues examined. The number of developing mast cells in the skin of W/Wv mice was much lower when grafted to tg/tg recipients than when grafted to normal (+/+) recipients. These results indicated that mast cell precursors of tg/tg mice were defective. When bone marrow cells of +/+ mice were transplanted, the number of developing mast cells was significantly lower in examined tissues of tg/tg recipients than in those of W/Wv recipients, suggesting that the tissue environment for mast cell development was defective in tg/tg mice. MITF appeared essential for the function of both mast cell precursors and tissue environments for their development. (Blood. 2004;104:1656-1661)