| Project/Area Number |
09670433
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Legal medicine
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| Research Institution | TOYAMA MEDICAL AND PHARMACEUTICAL UNIVERSITY |
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Principal Investigator |
KIMINATO Yoshihiko TOYAMA MEDICAL AND PHARMACEUTICAL UNIVERSITY Faculty of Medicine, Lecturer, 医学部, 講師 (30205512)
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| Co-Investigator(Kenkyū-buntansha) |
HATA Nobuhide TOYAMA MEDICAL AND PHARMACEUTICAL UNIVERSITY Faculty of Medicine, Research assis, 医学部, 教務職員 (40208509)
TAKIZAWA Hisao TOYAMA MEDICAL AND PHARMACEUTICAL UNIVERSITY Faculty of Medicine, Professor, 医学部, 教授 (90171579)
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| Project Period (FY) |
1997 – 1998
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| Project Status |
Completed (Fiscal Year 1998)
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| Budget Amount *help |
¥3,000,000 (Direct Cost: ¥3,000,000)
Fiscal Year 1998: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1997: ¥2,300,000 (Direct Cost: ¥2,300,000)
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| Keywords | the human ABO blood group genes / transcription / promoter assay / electrophoretic mobility shift assay / DNA methylation / tissue-specific expression / 5-aza-2'-deoxycytidine / CBF / NF-Y |
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| Research Abstract |
We have studied the transcriptional regulatory mechanism of the human histo-blood group ABO genes. The promoter assay using transient transfection showed that the sequence just upstream of the transcription start site (cap site) and an enhancer element which is located further upstream (between -3899 and -3618 bp from the transcription initiation site) are responsible for the transcriptional activity of the ABO genes in gastric cancer cells. Electrophoretic mobility shift assays showed that a transcriptional factor, CBF/NF-Y binds the minisatellite, which is essential for the enhancer activity, on between -3899 and -3618 bp from the transcription initiation site, However, the promoter assay demonstrated that the proximal promoter is active in the cells not expressing the ABO genes. Next, tissue-specific expression of the ABO genes was analyzed. The promoter region of the ABO genes fulfills the criteria for CpG island, having a G+C content of greater than 60 % and having a CpG/GpC ratio of at least 0.6. Methylated CpG islands are associated with long-range changes in chromatin, which mediate a closed, nucleosomal conformation, and transcriptional repression. Therefore, we have investigated the role of DNA methylation in the regulation of the expression of the human ABO blood group genes. Studies on the methylation of the ABO blood group gene promoter in cultured cells demonstrated that the promoter is methylated in vivo in the cells not expressing the ABO genes, and that hypomethylation of the promoter is correlated with constitutive gene expression. Demethylation of the promoter in vivo by treatment of the cells with 5-aza-2'-deoxycytidine led to the expression of A-antigens on gastric cancer cells and hypermethylation of the promoter in vitro suppressed the promoter activity. These studies suggest that alternations in DNA methylation may be one of the mechanisms regulating the tissue-specific expression of the ABO genes.
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