| Project/Area Number |
14340262
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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 |
動物生理・代謝
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| Research Institution | Chiba University |
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Principal Investigator |
OBINATA Takashi Chiba University, Department of Biology, Professor, 理学部, 教授 (40012413)
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| Co-Investigator(Kenkyū-buntansha) |
SATO Naruki Chiba University, Department of Biology, Instructor, 理学部, 助手 (40261896)
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| Project Period (FY) |
2002 – 2004
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| Project Status |
Completed (Fiscal Year 2004)
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| Budget Amount *help |
¥14,500,000 (Direct Cost: ¥14,500,000)
Fiscal Year 2004: ¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 2003: ¥2,800,000 (Direct Cost: ¥2,800,000)
Fiscal Year 2002: ¥9,600,000 (Direct Cost: ¥9,600,000)
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| Keywords | Cofilin / Actin-binding Protein / C-Proitein(Myosin-binding Protein C) / Myosin-binding Protein / Myofibrillogenesis / Cardiac Muscle Cells / Skeletal Muscle Cells / アクチン線維 / 筋原繊維形成 / アクチン結合タンパク質 |
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| Research Abstract |
1.Role of cofilin in myofibrillogenesis
Cofilin expression in cultured muscle cells was suppressed by an anti-sense method. Cofilin expression level was significantly lowered 3 days after injection of antisense-oligo nucleotides. When actin localization was examined with anti-actin antibody, bundles of actin filaments were detected but they were scattered in the cytoplasm without organizing into striated structures. In order to visualize actin dynamics in living muscle cells further, we labeled actin filaments in the cells with fluorescence-labeled C-terminal fragments of moesin, which contains actin-binding site but has no effects on actin dynamics. Actin assembly was traced up to another 3 days in the same cell after injection of anti-sense oligo nucleotides. Again, we observed that actin organization into myofibrils was severely disturbed in the cells with anti-sense oligo nucleotides. Thus, ordered assembly of actin into sarcomeric structures was clearly suppressed by lowering cofil
… More
in level. On the other hand, we generated chimeric mice that contain normal muscle cells and cofilin-deficient muscle cells in a chimeric pattern. We observed that severe damage emerged in skeletal muscle area, which lacks cofilin, namely irregular assembly of actin and myosin in sarcomere and degeneration of myofibers. These results indicate that cofilin plays a critical role for the regulated assembly of actin in the process of myofibril formation.
2.Functional domains in C-protein molecule
N-terminal fragments of chicken cardiac MyBP-C (NC) of different size, namely that contain domain C0-C4,C0-C1,C1-C2,C2-C4,were prepared in an E.coll expression system. Co-sedimentation assay showed that C0-C4 as well as C0-C1 bound to F-actin in a physiological salt solution. C0-C4 showed an inhibitory effect on actin-activated myosin-ATPase but this inhibition was much lowered in the presence of troponin-tropomyosin. Based on these data and together with those previously reported, we conclude that C-protein binds to myosin and connectin mainly at the C-terminal side while it binds to actin at the N-terminal side. Less
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