| Budget Amount *help |
¥15,050,000 (Direct Cost: ¥14,600,000、Indirect Cost: ¥450,000)
Fiscal Year 2007: ¥1,950,000 (Direct Cost: ¥1,500,000、Indirect Cost: ¥450,000)
Fiscal Year 2006: ¥2,300,000 (Direct Cost: ¥2,300,000)
Fiscal Year 2005: ¥2,300,000 (Direct Cost: ¥2,300,000)
Fiscal Year 2004: ¥8,500,000 (Direct Cost: ¥8,500,000)
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| Research Abstract |
The bending patterns of cilia and flagella are controlled by the influx of calcium ions through calcium channels that are present in the flagellar membrane. The elevated calcium concentration in the axoplasma alters the bending mode of the cilia and flagella. The flagellar channel in Chlamydomonas was studied in this project.
1. Identification of the ion channels expressed in the flagella
Multiple genes for voltage dependent calcium channel were found in the genome database of Chlamydomonas. The expression of the gene was confirmed by RT-PCR. One gene, CAV2, was found not to be expressed in ppr2 mutant, which has defect in generating flagellar current. An antibody raised against CAV2 immunostained flagella more intensely toward the distal part of the flagellum. We speculate that this distal localization is necessary for avoiding deflagellation, which is also activated by the increased calcium concentration. The expression level of CAV2 increased after deflagellation, which suggests that the gene is regulated as one of the flagella-related genes. Because photophobic response was not observed in a RNA-mediated knockdown strain for the expression of CAV2, CAV2 is probably the flagellar calcium channel required for the backward swimming in the photophobic response.
2. Analysis of TRP channel in the flagella
7 genes for TRP channels were found to be expressed in Chlamydomonas. Antibodies raised against the TRP channels revealed that 4 of them are expressed in the flagella. This is the first observation that motile flagella possess TRP channel.
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