| Project/Area Number |
05640760
|
|---|
| Research Category |
Grant-in-Aid for General Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Research Field |
動物生理・代謝
|
|---|
| Research Institution | University of Tsukuba |
|---|
Principal Investigator |
NUMATA Osamu Univ.Tsukuba Inst.Biol. Sciences Associate Prof., 生物科学系, 助教授 (50189354)
|
|---|
| Project Period (FY) |
1993 – 1994
|
| Project Status |
Completed (Fiscal Year 1994)
|
| Budget Amount *help |
¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1994: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1993: ¥1,200,000 (Direct Cost: ¥1,200,000)
|
|---|
| Keywords | Tetrahymena / citrate synthase / mitochondria / cytoskeleton / multifunction / 14nm filament protein / mmunoelectron microscopy / mitochondrial matrix |
|---|
| Research Abstract |
Recent cloning of a cDNA encoding Tetrahymena 14nm filament protein, indicated that its primary structure exhibits a high sequenceidentity with porcine citrate synthase. This led to the hypothesis that 14nm filament protein has dual functions as a citrate synthase in mitochondria and as the cytoskeleton in the cytoplasm.
To examine this hypothesis, we compared antigenecity and properties of enzyme activity between purified citrate synthase and 14nm filament protein. Anti-14nm filament protein antibody cross-reacted with citrate synthase and inhibited its enzyme activity. The enzyme properties of these proteins were identical.
To determine the number of the gene and mRNA of 14nm filament protein, Southern and Northern hybridization were performed. These results indicated that Tetrahymena possesses only single-type gene and a single-type mRNA of 14nm filament protein. Thus we concluded that one protein encoded from a single gene has two functions as a citrate synthase in mitochondria and as a 14nm filament protein in the cytoskeleton.
Immunoelectron microscopy showed that 14nm filament protein/citrate synthase formed filament bundles in mitochondrial matrix. To clarify the relationships between filament formation and citrate synthase activity, we analyzed the change of citrate synthase activity accompanied by filament formation in vitro. Citrate synthase activity of 14nm filament protein was low in polymerized state and high in depolymerized state. These results suggested that citrate synthase activity in mitochondria was regulated by filament formation.
|
