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Independent influence of strain difference and mi transcription factor on the expression of mouse mast cell chymases
Abstract:
Expression of mouse mast cell protease (mMCP) genes was examined with particular attention to the transactivation effect of mi transcription factor (MITF) and the expression differences between C57BL/6 (B6) and WB strains. We had reported the enhancing effect of MITF on the expression of mMCP-4, -5, and -6 genes in cultured mast cells (CMCs) of B6 strain, and in the present study we demonstrated the enhancing effect on the expression of mMCP-2 and -9 genes as well. The enhancing effect of MITF on the expression of mMCP-2, -4, -5, -6, and -9 genes was also detected in CMCs of the WB strain. The regulation of mMCP-2, -4, and -9 genes was localized to a specific promoter element (CANNTG) which was recognized and bound by MITF and which was conserved between the B6 and WB strains. On the other hand, the expression of mMCP-2, -4, and -9 genes was smaller in CMCs of the B6 strain when compared to their expression in CMCs of the WB strain. Although mMCP-5 is a chymase as mMCP-2, -4, and -9, and genes encoding all of the chymases are located on chromosome 14, the mMCP-5 gene was regulated in a manner distinct from mMCP-2, -4, and -9 genes.
Insights
Mouse mast cell proteases (mMCPs) gene expression is influenced by the microphthalmia-associated transcription factor (MITF). MITF enhances mMCP-2, -4, -5, -6, and -9 expression, with strain-specific differences observed in C57BL/6 and WB mice.
Area of Science:
- Immunology
- Molecular Biology
- Genetics
Background:
- Mast cell proteases (mMCPs) are key mediators of allergic inflammation.
- The microphthalmia-associated transcription factor (MITF) is a crucial regulator of melanocyte development and has been implicated in mast cell function.
- Previous studies indicated MITF enhances expression of certain mMCP genes in C57BL/6 (B6) mast cells.
Purpose of the Study:
- To investigate the transactivation effect of MITF on a broader range of mouse mast cell protease (mMCP) genes.
- To compare the expression patterns of mMCP genes between C57BL/6 (B6) and WB mouse strains.
- To identify specific regulatory elements involved in MITF-mediated mMCP gene expression.
Main Methods:
- Quantitative analysis of mMCP gene expression in cultured mast cells (CMCs) from B6 and WB strains.
- Electrophoretic mobility shift assays (EMSAs) to assess MITF binding to promoter regions.
- Sequence analysis of mMCP gene promoters.
Main Results:
- MITF enhances the expression of mMCP-2 and mMCP-9 genes in B6 CMCs, in addition to previously reported mMCP-4, -5, and -6.
- This enhancing effect of MITF was also observed in WB strain CMCs for mMCP-2, -4, -5, -6, and -9.
- A conserved CANNTG promoter element recognized by MITF was identified for mMCP-2, -4, and -9 regulation.
- Expression levels of mMCP-2, -4, and -9 were lower in B6 CMCs compared to WB CMCs.
- mMCP-5 gene regulation differed from mMCP-2, -4, and -9, despite sharing functional similarities and chromosomal location.
Conclusions:
- MITF plays a significant role in regulating multiple mMCP genes across different mouse strains.
- Specific promoter elements mediate MITF's transactivation of mMCP-2, -4, and -9.
- Strain-specific differences in mMCP gene expression exist, suggesting complex regulatory mechanisms beyond MITF.
- mMCP-5 exhibits distinct regulatory control compared to other chymase mMCP genes.