SgIGSF: a new mast-cell adhesion molecule used for attachment to fibroblasts and transcriptionally regulated by MITF.
Microphthalmia transcription factor (MITF) is a basic-helix-loop-helix-leucine zipper-type transcription factor. The mutant mi and Mi(wh) alleles encode MITFs with deletion and alteration of a single amino acid, respectively, whereas the tg is a null mutation. In coculture with NIH/3T3 fibroblasts, the numbers of cultured mast cells (CMCs) derived from C57BL/6 (B6)(mi/mi), B6(Miwh/Miwh), and B6(tg/tg) mice that adhered to NIH/3T3 fibroblasts were one third as large as the number of B6(+/+) CMCs that adhered to NIH/3T3 fibroblasts. From a cDNA library of B6(+/+) CMCs, we subtracted messenger RNAs expressed by B6(mi/mi) CMCs and found a clone encoding SgIGSF, a recently identified member of the immunoglobulin superfamily. Northern and Western blot analyses revealed that SgIGSF was expressed in B6(+/+) CMCs but not in CMCs derived from MITF mutants. Immunocytochemical analysis showed that SgIGSF localized to the cell-to-cell contact areas between B6(+/+) CMCs and NIH/3T3 fibroblasts. Transfection of B6(mi/mi) and B6(tg/tg) CMCs with SgIGSF cDNA normalized their adhesion to NIH/3T3 fibroblasts. NIH/3T3 fibroblasts did not express SgIGSF, indicating that SgIGSF acts as a heterophilic adhesion molecule. Transfection of B6(tg/tg) CMCs with normal MITF cDNA elevated their SgIGSF expression to normal levels. These results indicated that SgIGSF mediated the adhesion of CMCs to fibroblasts and that the transcription of SgIGSF was critically regulated by MITF.
Ito
Akihiko
A
Department of Pathology, Osaka University Medical School/Graduate School of Frontier Bioscience, Suita, Osaka, Japan.
Jippo
Tomoko
T
Wakayama
Tomohiko
T
Morii
Eiichi
E
Koma
Yu-ichiro
Y
Onda
Hiroaki
H
Nojima
Hiroshi
H
Iseki
Shoichi
S
Kitamura
Yukihiko
Y
D016475:3T3 Cells; D000818:Animals; D002448:Cell Adhesion; D000075982:Cell Adhesion Molecule-1; D015815:Cell Adhesion Molecules / Q000096:biosynthesis* / Q000235:genetics / Q000502:physiology; D018920:Coculture Techniques; D004268:DNA-Binding Proteins / Q000235:genetics / Q000502:physiology*; D005347:Fibroblasts / Q000166:cytology*; D005786:Gene Expression Regulation; D007136:Immunoglobulins / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D008407:Mast Cells / Q000737:chemistry / Q000166:cytology*; D008565:Membrane Proteins / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D051379:Mice; D008817:Mice, Mutant Strains; D051739:Microphthalmia-Associated Transcription Factor; D009154:Mutation; D012333:RNA, Messenger / Q000032:analysis / Q000302:isolation & purification; D014157:Transcription Factors / Q000235:genetics / Q000502:physiology*; D014158:Transcription, Genetic
C498598:Cadm1 protein, mouse; D000075982:Cell Adhesion Molecule-1; D015815:Cell Adhesion Molecules; D004268:DNA-Binding Proteins; D007136:Immunoglobulins; D008565:Membrane Proteins; D051739:Microphthalmia-Associated Transcription Factor; C497235:Mitf protein, mouse; D012333:RNA, Messenger; D014157:Transcription Factors