1999 Fiscal Year Final Research Report Summary
Genetical and biochemical studies on physiological function of intracellular nuclease of Aspergillus oryzae
| Project/Area Number |
10660075
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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 |
応用微生物学・応用生物化学
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| Research Institution | Meiji University (1999)
The University of Tokyo (1998) |
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Principal Investigator |
UOZUMI Takeshi Meiji University, School of Agriculture, Professor, 農学部, 教授 (40011978)
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| Co-Investigator(Kenkyū-buntansha) |
NAKAMURA Akira University of Tsukuba, Institute of Applied Biochemistry, Associate Professor, 応用生物化学系, 助教授 (10207863)
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| Project Period (FY) |
1998 – 1999
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| Keywords | nuclease / inhibitor / inhibitor protein / Aspergillus oryzae / Aspergillus / apoptosis / autolysis / caspase-activated DNase |
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| Research Abstract |
Aspergillus oryzae has nuclease O and its specific inhibitor protein in the cell. The nuclease and the inhibitor combine to make an inactive complex with a Ki of 3.2 x 10^<-12> (T.Uozumi et al., J.Biol. Chem., 251, 2808 (1976)). In the course of senescence of the fungi, especially under the deficiency of oxygen, the inhibitor protein is decomposed by protease, resulting in the activation of the nuclease, which in turn digests cellular nucleic acids. This study was intended to clarify the physiological function of intracellular nucleases including nuclease O.
We reported the cloning of nuclease O gene (nucO)(M.Sano et al., Curr. Genet., 30, 312 (1996)). In the present study, a mutant strain of A.oryzae with disrupted nucO gene was constructed. The mutant showed an apparently normal growth comparable to the wild strain, which suggested that nuclease O is not essential for growth of the fungi.
Recently, a caspase-activated DNase (CAD) and the specific inhibitor (ICAD) have been reported in animal cells. In the process of apoptosis, caspase degrades ICAD leading to the activation of CAD, which in turn degrades the cellular DNA.Physical properties of nuclease O (isoelectric point, pI=10.0) and the inhibitor (heat-stable, pI=4.1) are very similar to those of CAD and ICAD.So, there is a high possibility that the phenomenon of autolysis of A.oryzae corresponds to apoptosis of animal cells. More researches should be done to clarify the possibility.
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Research Products
(2 results)
