| Project/Area Number |
13206058
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| Research Category |
Grant-in-Aid for Scientific Research on Priority Areas
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| Allocation Type | Single-year Grants |
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| Review Section |
Biological Sciences
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| Research Institution | Tokyo Metropolitan University (2002-2004)
Kyushu University (2001) |
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Principal Investigator |
KATO Junrichi (2002-2004) Tokyo Metropolitan University, Department of Biological Sciences, Associate Professor, 都市教養学部, 助教授 (10194820)
三木 健良 (2001) 九州大学, 大学院・薬学研究院, 教授 (40037586)
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| Co-Investigator(Kenkyū-buntansha) |
KOMANO Teruya Tokyo Metropolitan University, Department of Biological Sciences, Professor, 都市教養学部, 教授 (00087131)
KATAYAMA Tsutomu Kyushu University, Department of Molecular Microbiology, Professor, 薬学研究院, 教授 (70264059)
MIKI Takeyoshi Fukuoka Dental College, Department of Physiological Science & Molecular, Professor, 歯学部, 教授 (40037586)
YAMAMOTO Yoshihiro Hyogo Medical College, Department of medical, Associate Professor, 医学部, 助教授 (60068567)
加藤 潤一 東京都立大学, 理学研究科, 助教授 (10194820)
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| Project Period (FY) |
2001 – 2004
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| Project Status |
Completed (Fiscal Year 2004)
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| Budget Amount *help |
¥89,800,000 (Direct Cost: ¥89,800,000)
Fiscal Year 2004: ¥22,400,000 (Direct Cost: ¥22,400,000)
Fiscal Year 2003: ¥22,400,000 (Direct Cost: ¥22,400,000)
Fiscal Year 2002: ¥21,000,000 (Direct Cost: ¥21,000,000)
Fiscal Year 2001: ¥24,000,000 (Direct Cost: ¥24,000,000)
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| Keywords | Escherichia coli / Minimal gene set / Essential gene / Chromosome / Deletion mutation / DNA replication / Genome / Molecular Biology / 遺伝学 / 細菌 / 遺伝子 / 遺伝子破壊 / 機能解析 / ネットワーク / トランスポゾン |
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| Research Abstract |
To identify the E. coli minimum set of genetic information, which is essential for cell proliferation, many transposon-insertion mutants were isolated and several types of long chromosomal deletions were systematically constructed. Using these long chromosomal deletions, we tried to identify all of the essential genetic information including small essential genes and essential cis-acting chromosome regions encoding no proteins or no RNA. The deletion mutations we have constructed cover more than 90% of the whole genome, and during construction of these deletions, we identified novel essential genes. We also succeeded in constructing an E. coil strain that lacks about 30% of the parental chromosome; there are no organisms, which have such significantly reduced genome.
The cellular functions of novel and non-characterized essential genes were analyzed. The hda gene encoding a DnaA-related protein was shown to be essential for the regulatory inactivation of a replication initiator, DnaA, and for the once-per-cell-cycle rule of replication. The novel ygfZ gene, which is involved in regulating the level of active-form of DnaA, is suggested to be a key factor in regulatory networks that act via tRNA modification. Two factors involved in the initiation of chromosome replication were identified: the novel DnaA-binding protein, DiaA, and the novel heat-shock protein, HspQ, which is involved in the degradation of DnaA. Other than DNA replication, the yadF gene encoding a carbonic anhydrase was shown to be essential and the mesJ gene was shown to be a lysidine synthetase, an RNA-modifying enzyme that plays a critical role in the accurate decoding of genetic information.
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