Involvement of transcription factor encoded by the mouse mi locus (MITF) in apoptosis of cultured mast cells induced by removal of interleukin-3.
Mast cells develop when spleen cells of mice are cultured in the medium containing interleukin (IL)-3. Cultured mast cells (CMCs) show apoptosis when they are incubated in the medium without IL-3. We obtained CMCs from tg/tg mice that did not express the transcription factor encoded by the mi gene (MITF) due to the integration of a transgene at its 5' flanking region. MITF is a member of the basic-helix-loop-helix-leucine zipper (bHLH-Zip) protein family of transcription factors. We investigated the effect of MITF on the apoptosis of CMCs after removal of IL-3. When cDNA encoding normal MITF ((+)-MITF) was introduced into tg/tg CMCs with the retroviral vector, the apoptosis of tg/tg CMCs was significantly accelerated. The mutant mi allele represents a deletion of an arginine at the basic domain of MITF. The apoptosis of tg/tg CMCs was not accelerated by the introduction of cDNA encoding mi-MITF. The overexpression of (+)-MITF was not prerequisite to the acceleration of the apoptosis, as the apoptotic process proceeded faster in +/+ CMCs than in mi/mi CMCs. The Ba/F3 lymphoid cell line is also dependent on IL-3, and Ba/F3 cells show apoptosis after removal of IL-3. The c-myc gene encodes another transcription factor of the bHLH-Zip family, and the overexpression of the c-myc gene accelerated the apoptosis of Ba/F3 cells. However, the overexpression of (+)-MITF did not accelerate the apoptosis of Ba/F3 cells. The (+)-MITF appeared to play some roles for the acceleration of the apoptosis specifically in the mast cell lineage.
Tsujimura
T
T
Department of Pathology, Osaka University Medical School, Suita, Japan.
Hashimoto
K
K
Morii
E
E
Tunio
G M
GM
Tsujino
K
K
Kondo
T
T
Kanakura
Y
Y
Kitamura
Y
Y
D000818:Animals; D017209:Apoptosis / Q000235:genetics; D015152:Blotting, Northern; D002452:Cell Count; D002478:Cells, Cultured; D053938:DNA Fragmentation; D017931:DNA Primers / Q000737:chemistry; D004268:DNA-Binding Proteins / Q000235:genetics*; D005260:Female; D015971:Gene Expression Regulation, Enzymologic; D007150:Immunohistochemistry; D007377:Interleukin-3 / Q000378:metabolism*; D008297:Male; D008407:Mast Cells / Q000502:physiology*; D051379:Mice; D008810:Mice, Inbred C57BL; D008817:Mice, Mutant Strains; D051739:Microphthalmia-Associated Transcription Factor; D013154:Spleen / Q000166:cytology / Q000276:immunology; D014157:Transcription Factors / Q000235:genetics*
D017931:DNA Primers; D004268:DNA-Binding Proteins; D007377:Interleukin-3; D051739:Microphthalmia-Associated Transcription Factor; C497235:Mitf protein, mouse; D014157:Transcription Factors