1997 Fiscal Year Final Research Report Summary
Regulation of histamine synthesis and degradation at the gene level
| Project/Area Number |
08044230
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| Research Category |
Grant-in-Aid for international Scientific Research
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| Allocation Type | Single-year Grants |
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| Section | Joint Research |
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| Research Field |
General pharmacology
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| Research Institution | Tohoku University |
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Principal Investigator |
WATANABE Takehiko Tohoku University ; Medicine ; Professor, 医学部, 教授 (70028356)
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| Co-Investigator(Kenkyū-buntansha) |
ナギー アンドラス サミュエル, ルーネンフェルト研究所, 主任研究員
FALUS Andras Semmelweiss University ; Medicine ; Professor, 教授
ICHIKAWA Atsushi Kyoto University ; Pharma ; Professor, 薬学部, 教授 (10025695)
YAMAUCHI Kohei Iwate Medical School ; Medicine ; Assistant Professor, 医学部, 助教授 (20200579)
OHTSU Hiroshi Tohoku University ; Medicine ; Research Associante, 医学部, 助手 (60250742)
NAGY Andras Samuel-Lunenfeld Research Institute ; Biology ; Senior Staff Scientist
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| Project Period (FY) |
1996 – 1997
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| Keywords | histamine / histidine decarboxylase / histamine N-methyltransferase / gene expression / knockout mouse / mast cell |
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| Research Abstract |
Histidine decarboxylase (HDC) is a unique enzyme catalyzing synthesis reaction of histamine from histidine and its expression is restricted in mast cell and basophil lineage among the hematopoietic cells. We found that the methylation of promoter region of this gene suppress the transcription and those cell lineages (mast cell and basophil) have exclusively demethylated state around promoter region. Azacytidine, an demethylating reagent, produce the demethylation of promoter region of HDC gene and induce HDC expression in P815 cells, suggesting that the methylation is mechanically very important for the cell specific expression of this gene. We are going to seek for other DNase I hypersensitive sites other than the site we already found. We hope these sites contain cell specific cis-element to contribute for cell-specific demethylation which will lead the future investigation. We also proved that 74 kDa nascent HDC protein are translated in cytosol and targeted into ER to produce 53 kDa processed protein. We found that the 74 kDa protein is not only converted to 53 kDa protein but also catabolyzed viaubiquitinization and this speed of catabolism is much faster than that of the 53 kDa protein. We made HDC knockout mice by homologous recombination technique and proved that the knockout mice possess no histamine in the body (ahistaminergic mice). This mice Seemed to grow normally and were fertile. The proliferation pattern of this mice follows Mendelian law, therefore there seems to be no embryonic death. We are planning to assess the behavior and allergy using knockout mice. Once turned to catabolizing enzyme of histamine, we cloned human histamine N-methyltransferase (HMT) gene. HMT gene consists of 6 exons and resides in 2nd Chromosome q13-21. We also started to construct a plasmid for transgenic mice to produce high amount of rat HMT.
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