| Project/Area Number |
18570152
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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 |
Biophysics
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| Research Institution | Kyoto University |
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Principal Investigator |
IMAI Hiroo Kyoto University, Primate Research Institute, Associate Professor (60314176)
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| Project Period (FY) |
2006 – 2007
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| Project Status |
Completed (Fiscal Year 2007)
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| Budget Amount *help |
¥3,860,000 (Direct Cost: ¥3,500,000、Indirect Cost: ¥360,000)
Fiscal Year 2007: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000)
Fiscal Year 2006: ¥2,300,000 (Direct Cost: ¥2,300,000)
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| Keywords | rhodopsin / knock-in / vision / ES cell / retina / protein / G-protein / cone / 光 |
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| Research Abstract |
Most vertebrate retinas contain two types of photoreceptor cells, rods and c ones, which are responsible for twilight and daylight vision, respectively. The rod and cone visual pigments exhibit different molecular properties before and after light absorption. That is, cone pigments show rapid formation and decay of G protein-activating states upon absorption of light, while they show high susceptibility to hydroxylamine in the dark. The amino acid residues responsible for the former difference have been identified ; We have identified the site and demonstrated the effect of the site using knock-in mice. However, the residue(s) for the latter difference have not been identified due to the vast divergence of amino acid sequence between rod and cone pigments. We have cloned and expressed primate rhodopsin and compared its susceptibility to hydroxylamine with bovine rhodopsin. As a result, primate rhodopsin showed significantly higher susceptibility than bovine rhodopsin. We also designed and expressed site directed mutants of primate and bovine rhodopsin to identify the amino acid residue(s) responsible for the difference. Some mutants in which the hydrophobic residues in the transmembrane regions are changed showed altered susceptibility to hydroxylamine. These results suggest that the susceptibility to hydroxylamine is regulated by the hydrophobic interact ions in transmembrane regions. Because the residues in cone pigments are different from bovine rhodopsin, these findings would give a due to elucidating the mechanism for the difference in the susceptibility to hydroxylamine between rod and cone visual pigments.
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