CAPPUCCINO AND SPIRE - 2 UNIQUE MATERNAL-EFFECT LOCI REQUIRED FOR BOTH THE ANTEROPOSTERIOR AND DORSOVENTRAL PATTERNS OF THE DROSOPHILA EMBRYO
CAPPUCCINO AND SPIRE - 2 UNIQUE MATERNAL-EFFECT LOCI REQUIRED FOR BOTH THE ANTEROPOSTERIOR AND DORSOVENTRAL PATTERNS OF THE DROSOPHILA EMBRYO
复制标题
DOI：
10.1101/gad.3.9.1437
复制
发表时间：
1989-09-01
影响因子：
10.5
通讯作者：
SCHUPBACH, T
中科院分区：
文献类型：
--
作者：
MANSEAU, LJ;SCHUPBACH, T
卡布奇诺和尖顶是果蝇特有的母性效应基因，参与了早期胚胎前后轴和背腹轴的图案形成。突变雌性产生的胚胎没有极细胞、极颗粒和正常的腹部节段。它们与后一组母系效应基因具有相同的缺陷。虽然胚胎的腹部部分是有缺陷的，但在双突变与双尾D的组合中，腹部部分可以在卵子的前半部分形成。这表明突变的雌性胚胎含有腹部分割所需的“后决定因素”(Nusslein-Volhard等人)。1987)，表明野生型基因产物不是生产后决定簇所必需的，而是其定位或稳定所必需的。VasA蛋白是极性颗粒的一种成分，不定位于突变卵室或胚胎的后极，这为突变雌性卵室后极物质的定位或稳定是有缺陷的假设提供了额外的支持。突变最强等位基因的雌性也会产生背部胚胎。表型分析表明，这些背侧胚胎也存在腹部节段缺陷。突变的表型可以按照一系列严重性递增的顺序排列。极细胞的形成对功能基因产物的丢失最敏感，其次是腹部节段，而正常的背腹模式对功能基因产物的丢失最不敏感。此外，突变的雌性昆虫含有看起来像是背靠背的卵室，导致产生的卵带有背靠背的蛋壳。生殖系马赛克表明，在卵母细胞-哺育细胞复合体中需要卡布奇诺和尖顶。这表明，蛋壳的表型是由底层生殖细胞中的模式改变所致。此外，我们还根据对卡布奇诺或尖顶双突变雌性所产生的卵和胚胎以及其他影响卵和胚胎模式的基因座的分析，定义了几个早期模式基因座之间的上位关系。基于我们目前对参与这一过程的基因的了解，我们制定了背腹模式早期步骤的工作模型。
cappuccino and spire are unique Drosophila maternal-effect loci that participate in pattern formation in both the anteroposterior and dorsoventral axes of the early embryo. Mutant females produce embryos lacking pole cells, polar granules, and normal abdominal segmentation. They share these defects with the posterior group of maternal-effect genes. Although embryos are defective in abdominal segmentation, in double mutant combinations with Bicaudal D, abdominal segments can be formed in the anterior half of the egg. This indicates that embryos produced by mutant females contain the ''posterior determinant'' required for abdominal segmentation (Nusslein-Volhard et al. 1987) and suggests that the wild-type gene products are not required for production of the posterior determinant but, rather, for its localization or stabilization. The vasa protein, a component of polar granules, is not localized at the posterior pole of mutant egg chambers or embryos, providing additional support for the hypothesis that localization to or stabilization of substances at the posterior pole of the egg chamber is defective in mutant females. Females mutant for the strongest alleles also produce dorsalized embryos. Phenotypic analysis reveals that these dorsalized embryos also have abdominal segmentation defects. The mutant phenotypes can be ordered in a series of increasing severity. Pole cell formation is most sensitive to loss of functional gene products, followed by abdominal segmentation, whereas normal dorsoventral patterning is the least sensitive to loss of functional gene products. In addition, mutant females contain egg chambers that appear to be dorsalized, resulting in the production of eggs with dorsalized eggshells. Germ-line mosaics indicate that cappuccino and spire are required in the oocyte-nurse cell complex. This suggests that the eggshell phenotype results from altered pattern in the underlying germ cell. Also, we defined the epistatic relationships between several early patterning loci, on the basis of an analysis of the eggs and embryos produced by females doubly mutant for cappuccino or spire and other loci that affect the pattern of both the egg and the embryo. On the basis of our current knowledge of the genes involved in this process, we formulated a working model for the early steps in dorsoventral patterning.