| Project/Area Number |
12470031
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
General medical chemistry
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| Research Institution | Jikei University School of Medicine |
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Principal Investigator |
MATSUFUJI Senya THE JIKEI UNIVERSITY SCHOOL OF MEDICINE, FACULTY OF MEDICINE, PROFESSOR, 医学部, 教授 (50192753)
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| Project Period (FY) |
2000 – 2003
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| Project Status |
Completed (Fiscal Year 2003)
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| Budget Amount *help |
¥6,700,000 (Direct Cost: ¥6,700,000)
Fiscal Year 2003: ¥2,300,000 (Direct Cost: ¥2,300,000)
Fiscal Year 2002: ¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 2001: ¥2,200,000 (Direct Cost: ¥2,200,000)
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| Keywords | ANTIZYME / KNOCKOUT MOUSE / ORNITHINE DECARBOXYLASE / POLYAMINE / FETAL HEMATOPOIESIS / EMBRYONIC LETHALITY / MODIFIER GENE / MIN MOUSE / 二次造血 / 発がん / Modifier gene / 腸管ポリープ / 培養胎児線維芽細胞 / アンチザイム2 / 二重欠損マウス / 胎生部分致死 / ジフルオロメチルオルニチン |
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| Research Abstract |
1) Antizymes are polyamine-induced proteins that negatively regulate cellular polyamines. We previously reported that homozygous AZ1 knockout mice with a mixed genetic background are partially embryonic lethal. Homozygous embryos with the C57BL/6J background showed a high mortality rate at embryonic day (E) 13.5-16.5. Hepatic hypoplasia was the earliest abnormality ever detected. Subsequent analysis revealed a reduction of hepatic hemopoietic cells with apoptotic morphology at E12.5-13.5 and anemia with increased erythroblasts in the peripheral circulation, indicating that the secondary embryonic hematopojesis in the liver was a most affected process in the AZ1 knockout mice. Presence of modifier gene(s) for the lethal phenotype of AZ1 knockout mice was indicated in our genetic analysis. To identify the modifier gene(s) using positional assignment, we have prepared a congenic line in MSKR mice, a strain originated from wild molossinus mice in Japan.
2) Studies using primary and immortalized cultured cells derived from AZ1 knockout mice demonstrated that ODC repression by polyamines was retarded in these cells and that AZ2 partially compensated the polyamine regulation. Thus AZ2 has activities to repress ODC and inhibit polyamine uptake both in a polyamine-dependent manner.
3) We also prepared AZ2 knockout mice. Homozygous AZ2 knockout mice showed no apparent phenotype. AZ1-AZ2 double homozygous knockout mice were complete embryonic lethal by E14.5. The systemic developmental retardation started by E10.5 before the formation of liver, suggesting that the cause of death in the double knockout embryos differs from AZ1 knockouts.
4) Long term observation of survivors failed to show the increase in the tumorigenesis in AZ1 homozygotes. However, crossing of AZ1 knockout mice and APC-deficient mm mice demonstrated increases in the number and size of intestinal adenomas in the presence of the heterozygous AZ1 mutation in min mice.
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