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Molecular mechanism of sex determination in lepidopteran insects-The sex chromosomes regulate sex-specific splicing of dsx homologs.

鳞翅目昆虫性别决定的分子机制——性染色体调节 dsx 同源物的性别特异性剪接。

基本信息

批准号：
16208006
负责人：
SHIMADA Toru
金额：
$ 29.95万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
2004
资助国家：
日本
起止时间：
2004 至 2006
项目状态：
已结题

项目摘要

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.

1.Bmdsx基因性别特异性选择性剪接的分子机制。Bmdsx是家蚕（Bombyx mori）的性别决定基因，位于第25^< >染色体上。构建了一个包含1-5外显子和2-4内含子的Bmdsx基因，该基因仅包含5′和3′端序列，并通过piggyback转化系统导入家蚕种系。成功地将Bmdsx基因转录并拼接到转基因家蚕的性别依赖性mrna中。我们还发现5'端序列包含一个顺式元件，这是雄性特异性剪接所必需的。在紫外交联实验中，一种蛋白p40与顺式元件结合。我们进行了RNAi实验，证明p40基因对bmdsx的雄性型剪接至关重要。W染色体上的雌性决定基因。蚕的W染色体应该编码了一个强有力的雌性决定因素，尽管它是未知的。我们利用各种类型的染色体畸变将女性的行列式映射到Rikishi区域。虽然在Rikishi地区发现了一些蛋白质编码基因，但在一个密切相关的物种，Bombyx mandarina的W染色体上没有发现它们。Z染色体的结构和功能。基因组信息预测了Z染色体上655个蛋白质编码基因。男性的神经和肌肉系统基因往往位于Z染色体上。例如，四种生物钟成分中的三种（per, tim, clk, cyc）被映射到Z染色体上。生殖细胞的性分化，尤指卵母细胞的分化采用SAGE分析方法分析卵母细胞发育过程中的阶段依赖性基因表达。我们注意到一种新的非编码RNA （Ovachamp）在卵巢中大量表达。Ovachamp的RNAi显示了一个有趣的表型，即未发育的卵母细胞，这表明该基因对卵发生至关重要。