| Project/Area Number |
16208006
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Applied entomology
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| Research Institution | The University of Tokyo |
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Principal Investigator |
SHIMADA Toru The University of Tokyo, Graduate School of Agricultural and Life Sciences, Professor, 大学院農学生命科学研究科, 教授 (20202111)
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| Co-Investigator(Kenkyū-buntansha) |
ABE Hiroaki Tokyo University of Agriculture and Technology, Department of Biological Production Faculty of Agriculture, Assistant Professor, 大学院共生科学技術研究部, 助手 (80222660)
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| Project Period (FY) |
2004 – 2006
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| Project Status |
Completed (Fiscal Year 2006)
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| Budget Amount *help |
¥46,800,000 (Direct Cost: ¥36,000,000、Indirect Cost: ¥10,800,000)
Fiscal Year 2006: ¥4,940,000 (Direct Cost: ¥3,800,000、Indirect Cost: ¥1,140,000)
Fiscal Year 2005: ¥14,690,000 (Direct Cost: ¥11,300,000、Indirect Cost: ¥3,390,000)
Fiscal Year 2004: ¥27,170,000 (Direct Cost: ¥20,900,000、Indirect Cost: ¥6,270,000)
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| Keywords | W chromosome / gene dosage compensation / sex-specific splicing / sex-determining genes / DM domain / RNAi / non-coding RNA / oogenesis / doublesex / 染色体異変 / 限性品種 / SAGE / DNAメチル化 / カイコとクワコ / 染色体変異 / 形質変換昆虫 / トランスポゾン / イントロン |
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| Research Abstract |
1.Molecular mechanism of sex-specific alternative splicing in Bmdsx.
Bmdsx is a sex determining gene located on the 25^<th> chromosome in the silkworm, Bombyx mori. A mini Bmdsx gene containing exons 1-5 and mini intorons 2-4, which contained only the 5' and 3' ends sequences, was constructed and introduced into the germ line of the silkworm by the piggyBac-based transformation system. The mini Bmdsx transgene was successfully transcribed and spliced into the sex-dependent mRNAs in the transgenic silkworms. We also found that the 5' end sequences contained a cis element required for the male-specific splicing. In the UV-cross link experiment, a protein, p40, was bound to the cis element. We performed an RNAi experiment and proved that the p40 gene was essential for the male-type splicing of Bmdsx.
2.Female determining gene on the W chromosome.
The W chromosome should encode a potent female determinant for the silkworm though it is unknown. We mapped the female determinant into the Rikishi region using various kind of the chromosome aberrations. Although a few protein-coding genes were found in the Rikishi region, they are not found on the W chromosome of a closely-related species, Bombyx mandarina.
3.Structure and function of the Z chromosome.
The genome information predicted 655 protein-coding genes on the Z chromosome. The genes for nervous and muscular systems in the males tend to locate on the Z chromosome. For example, three of the four circadian clock components (per, tim, clk, cyc) were mapped onto the Z chromosome.
4.Sexual differentiation of germ cells, especially differentiation of the oocyte.
A SAGE analysis were performed to analyze stage-dependent gene expression in oocyte development. We noticed that a novel non-coding RNA (Ovachamp) was abundantly expressed in the ovary. The RNAi of Ovachamp showed an interesting phenotype, i. e. undeveloped oocytes, suggesting that this gene is essential for oogenesis.
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