1992 Fiscal Year Final Research Report Summary
Genetic Analysis of myofibrillar-genesis using Drosophila melanogaster
| Project/Area Number |
02454550
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
分子遺伝学・分子生理学
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| Research Institution | The University of Tokyo |
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Principal Investigator |
MOGAMI Kaname The University of Tokyo Faculty of Science Research Associate, 理学部, 助手 (80174332)
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| Project Period (FY) |
1990 – 1992
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| Keywords | Drosophila / Muscle mutation / Myofibril / P-element / Actin |
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| Research Abstract |
The aim of this research is to understand mechanisms of myofibril formation using indirect flight muscle of the fruit fly Drosophila melanogaster. Since the muscle is highly differentiated for flight, many muscle mutations are available without affecting viability. Two projects were performed in this study. First, dominant flightless mutants were isolated using single P element mutagenesis. Nine second chromosomal mutants and eighty third chromosomal mutants were isolated. Second, a number of actin mutants were newly isolated to examine roles of each amino acid residue. The gene is 88F actin gene that is expressed only in the indirect flight muscle. A highly efficient method to isolate third chromosomal flightless mutants was developed. The mutated genes were amplified by the polymerase chain reaction, and their DNA sequences were directly determined. So far, thirty mutants were newly identified. These mutants were analyzed genetically, and their thorax proteins were examined by two-dimensional polyacrylamide gel electrophoresis. Myofibrills of their indirect flight muscles and muscle fibers were also examined under a microscope The eleven missense mutations were found to be classified as follows. 1. amorphic (V103E, E57K): The phenotypes of these mutants are almost identical with those of nonsense mutations that produce very short truncated polypepdides. This suggests that the structure of the mutated actin molecules should be disrupted totally. 2. Hypomorphic (P307L): The phenotype of this mutant is better than the amorphic mutations. The mutant actin seems to copolymerize with normal actin. 3. antimorphic (others): The flightless phenotypes of these mutants are not rescued even if two doses of normal actin genes are present. The mutated actins seem to keep some normal structure and somehow interfere with the normal molecules. Thus, structure and function of mutated actin molecules were assessed by examining individual mutants.
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