Effect of the mi allele on mast cells, basophils, natural killer cells, and osteoclasts in C57BI/6J mice

Abstract

The osteopetrotic, microphthalmic (mi/mi) mouse lacks functional osteoclasts and has also been reported to be deficient in mast cells and natural-killer (NK) cells. The later deficiencies could be secondary to the osteopetrotic marrow, or a direct result of the mi allele. Therefore, heterozygotes were examined for these cell types, since these mice do not exhibit osteopetrosis. Adult +/mi animals have approximately 50%, and mi/mi animals examined by histologic techniques or tissue histamine levels have 0-10%, of the peritoneal, dermal, and intestinal mast cells compared with that of +/+ animals. Leukocyte histamine, indicative of the number of basophils, demonstrates the same pattern. Histamine content per mast cell in +/+ and +/mi animals is identical. The number of large granular lymphocytes (LGL) in splenic leukocyte preparations from +/mi animals is 50% that of +/+ animals, and these cells are undetectable in preparations from mi/mi mice. NK activity against YAC-1 cells paralleled the number of LGL present. The resorptive response of neonatal calvaria to parathyroid hormone was delayed in the case of cultured +/mi bone compared with that of +/+ bone, but the final rate of calcium release was identical. These data indicate that 1) the presence of one mi allele can affect the development of four distinct cell types, and 2) osteopetrosis alone does not account for the lack of mast cells, basophils, and NK cells in mi/mi mice.

Adipose Tissue as a Dedicated Reservoir of Functional Mast Cell Progenitors

“…PU.1, GATA-2, GATA-3, and the microphthalmia-associated transcription factor are essential for mast cell development [22][23][24][25]. We showed that adiposederived CFCs express these four transcription factors as peritoneal cell-derived mast cell controls (Fig.…”

Cyclic AMP a Key Messenger in the Regulation of Skin Pigmentation

“…MITF is expressed in melanocytes, in retina pigment cells, in mast cells and in osteoclasts (50,51). Pigmentation defects in mi mice seem to be a result of the absence of melanocytes.…”

Synergy of PEBP2/CBF with mi transcription factor (MITF) for transactivation of mouse mast cell protease 6 gene

“…The mi-MITF is defective in the DNA binding activity and the nuclear localization potential, and it does not transactivate target genes Takebayashi et al, 1996;Tsujimura et al, 1996;Jippo et al, 1997;Ito et al, 1998;Kim et al, 1998). The mi/mi mice show microphthalmia, depletion of pigment in both hair and eyes, osteopetrosis, and decrease of mast cells (Silvers, 1979;Green, 1981;Stevens and Loutit, 1982;Stechschulte et al, 1987). In addition to the decrease in number, the phenotype of mast cells is abnormal in mi/mi mice (Ebi et al, 1990(Ebi et al, , 1992Kasugai et al, 1993;Isozaki et al, 1994;Jippo et al, 1994).…”