Abnormal expression of mouse mast cell protease 5 gene in cultured mast cells derived from mutant mi/mi mice.
Mast cells contain a lot of mast cell-specific proteases. We have reported that the expression of mouse mast cell protease 6 (MMCP-6) is remarkably reduced in both cultured mast cells (CMCs) and skin mast cells of mi/mi mutant mice. In the present study, we found that the expression of MMCP-5 was reduced in CMCs but not in skin mast cells of mi/mi mice, and we compared the regulation mechanisms of MMCP-5 with those of MMCP-6. The mi locus encodes a member of the basic-helix-loop-helix-leucine zipper (bHLH-Zip) protein family of transcription factors (hereafter called MITF). The consensus sequence recognized and bound by bHLH-Zip transcription factors is CANNTG. The overexpression of the normal (+) MITF but not of mi-MITF normalized the poor expression of the MMCP-5 gene in mi/mi CMCs, indicating the involvement of +-MITF in transactivation of the MMCP-5 gene. Although +-MITF directly bound CANNTG motifs in the promoter region of the MMCP-6 gene and transactivated it, the binding of +-MITF to the CAGTTG motif in the promoter region of the MMCP-5 gene was not detectable. The +-MITF appeared to regulate the transactivation of the MMCP-5 gene indirectly. Moreover, addition of stem cell factor to the medium normalized the expression of the MMCP-5 but not of the MMCP-6 gene in mi/mi CMCs. Despite the significant reduction of both MMCP-5 and MMCP-6 expressions in mi/mi CMCs, their regulation mechanisms appeared to be different.
Morii
E
E
Department of Pathology, Osaka University Medical School, Suita, Japan.
Jippo
T
T
Tsujimura
T
T
Hashimoto
K
K
Kim
D K
DK
Lee
Y M
YM
Ogihara
H
H
Tsujino
K
K
Kim
H M
HM
Kitamura
Y
Y
D000818:Animals; D001483:Base Sequence; D002478:Cells, Cultured; D004268:DNA-Binding Proteins / Q000235:genetics / Q000502:physiology*; D015870:Gene Expression; D018257:Helix-Loop-Helix Motifs / Q000502:physiology*; D017403:In Situ Hybridization; D016350:Leucine Zippers / Q000502:physiology*; D008407:Mast Cells / Q000201:enzymology*; D051379:Mice; D008810:Mice, Inbred C57BL; D008817:Mice, Mutant Strains; D051739:Microphthalmia-Associated Transcription Factor; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D012697:Serine Endopeptidases / Q000096:biosynthesis / Q000235:genetics*; D012867:Skin / Q000166:cytology; D014157:Transcription Factors / Q000502:physiology*
D004268:DNA-Binding Proteins; D051739:Microphthalmia-Associated Transcription Factor; C497235:Mitf protein, mouse; D014157:Transcription Factors; D012697:Serine Endopeptidases