1992 Fiscal Year Final Research Report Summary
A study on the temperature-dependent modes of selective transmission of mitochondria in Drosophila
| Project/Area Number |
03640538
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
遺伝学
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| Research Institution | Ochanomizu University |
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Principal Investigator |
MATSUURA Etsuko T. (Instructor) Dept. of Biology Ochanomizu University, 理学部, 助手 (00111691)
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| Co-Investigator(Kenkyū-buntansha) |
NIKI Yuzo (Associate Professor) Dept. of Biology Ibaraki University, 理学部, 助教授 (00134164)
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| Project Period (FY) |
1991 – 1992
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| Keywords | Drosophila / Mitochondrial transmission / Mitochondrial DNA / Heteroplasmy |
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| Research Abstract |
The temperature-dependent modes of selective transmission of mitochondrial DNA (mtDNA) were investigated in heteroplasmic lines which were established by germ-plasm transplantation in Drosophila melanogaster. The effects of the nuclear genome on the temperature- dependency were demonstrated in two sets of heteroplasmic lines: one established by reciprocal transplantation of germ plasm in D. melanogaster and the other derived from two D. melanogaster heteroplasmic lines possessing D. mauritiana mtDNA in which the nuclear genomes were reciprocally substituted. In each set, the temperature- dependent modes of selective transmission of the same two types of mtDNA were different depending on the nuclear genomes. Involvement of propagation of mitochondria and/or mtDNA replication in selective transmission was suggested from three observations, using heteroplasmic lines with appropriate combinations of two types of mtDNA and the nuclear genome. First, the intensity of selection was strongly affected by the temperature at the stage of oogenesis among the various developmental stages. Secondly, the intensity of selection was affected by some nucleotide sequences in the A+T-rich region containing the origin of replication. Thirdly, in heteroplasmic lines possessing two different sizes of mtDNA, the smaller one was selectively transmitted. In the last two cases,the effects of temperature were not clear. These results indicate that the nuclear genome is involved in determining the temperature-dependent mode of the selective transmission of mtDNA. They also suggest that the selective transmission is based on the differences in mtDNA replication. The present results will greatly contribute to clarify the molecular mechanisms of the regulation of mitochondrial transmission in eucaryotic cells.
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