| Budget Amount *help |
¥2,300,000 (Direct Cost: ¥2,300,000)
Fiscal Year 1996: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1995: ¥1,600,000 (Direct Cost: ¥1,600,000)
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| Research Abstract |
In order to investigate the transport pathway of functional proteins in the cells in situ, protein transport was interrupted by the use of mutant Rab proteins in the organellaspecific manner. Full-length cDNAs of 10 Drosophila Rab proteins were cloned and sequenced. Using the cDNAs, corresponding Rab proteins were synthesized in E.coli cells, and injected into the mice to produce their antisera. Localization of Rab proteins were then examined by the use of these antisera. Major fraction of each Rab proteins was in the membrane-bound form, which would probably resides in a particular cell organella. Immunohistological investigation of DRab1 protein revealed that its distribution overlaps that of the Golgi body in the photoreceptor cells.
Transgenic flies expressing the dominant-negative versions of DRab1, DRab2 and DRabRP4 were constructed with the germ-line transformation technique. No apparent affects of the mutant Drab expression were found in the DRabRP4 transformant. In the dominant negative mutant of DRab2, most rhodopsin molecules were matured normally but a small fraction of them stayd just before full-mature form. This result suggests that Rab2 may be involved in a late stage of vesicle transport in Dorosophila photoreceptor cells. In contrast, remarkable affects on rhodopsin transport and cell structure were observed in the DRab1 transgenic mutant. Immature rhodopsin binding a large oligosaccharide chain was accumulated in the mutant. In the photoreceptor cells, Golgi bodies were disassembled and a numerous rER surrounded a nucleus. These results indicates that DRab1 plays an essential role in the vesicle transport between rER and Golgi body.
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