Gene expression in relation to oogenesis, embryogenesis and development in Bombyx mori

利用家蚕突变体及其假想的家蚕祖先野桑蚕，分析了家蚕基因的表达过程。1.由于多基因家族编码的复杂结构的形态发生，人们对蛋壳绒毛膜很感兴趣。扫描电子显微镜观察到的橘子蛋壳在最外层非常特异，这似乎与该物种的户外栖息地相匹配。柑橘绒毛膜中含有在桑树中很少检测到的蛋白质成分。基因组DNA的Southern杂交分析结果与桑树的不同。因此，与家蚕相比，野桑蚕可能在绒毛膜基因座上有一个不同的基因集。然而，关于与最外层蛋白质相关的DNA，这两个物种之间有令人惊讶的同源性。可以合理地假设外层在功能上是重要的，因为它与环境和…直接接触更多相关序列在进化过程中是稳定的。需要对柑橘基因组进行进一步的分析，以揭示特定的外层结构是如何确定的。2.家蚕幼虫的血淋巴中含有类胡萝卜素结合蛋白。先前已知一种缺乏血淋巴类胡萝卜素的突变体，有趣的是，已证实该突变体也具有在许多生化特征方面与正常类胡萝卜素结合蛋白相同的蛋白质。结果表明，可能在中肠中存在一种基因控制的机制，在这种机制下，类胡萝卜素分子被藏匿在它们特定的结合蛋白中。3.家蚕卵的大小和形态都发生了改变，出现了许多突变。对其中一些突变体的形态和生化分析表明，卵泡上皮细胞在决定鸡蛋性状方面起着关键作用。这些结果为理解复杂的卵子发生过程提供了一种途径。较少

Gene expression processes were analyzed by using mutants of the domestic silkworm, Bombyx mori, as well as using its supposed ancestor Bombyx mandarina. 1. The eggshell chorion was of interest because of the morphogenesis of its complex structure coded for by the multigene families. Scanning electron microscopy of the mandarina eggshell was very specific at the outermost layer, which seemed to match the outdoor habitation of this species. The mandarina chorion had protein components which were scarcely detected in mori. Southern blot hybridization analysis of the genomic DNA of mandarina differed from those of mori. Thus, mandarina may have a distinct gene set at the chorion locus in comparison with the domestic silkworm. Nevertheless, with respect to the DNA related to the outermost layer proteins, there was a surprising homology between the two species. It may be reasonable to suppose that the outer layer is functionally important because of its direct contact with the environment an … More d the relevant sequences are stable during evolution. Further analysis of the mandarina genome is needed to uncover how the specific outer layer structure is determined. 2. The silkworm larvase were found to have a carotenoid binding protein in the haemolymph. Previously a mutant which lacks the hemolymph carotenoid has been known, interestingly, it was confirmed that the mutant also possesses the protein that was identical to the normal carotenoid binding protein in terms of many biochemical characteristics. The results suggested that there may be, probably in the midgut, a genetically controlled mechanism under which carotenoid molecules are harbored into their specific binding protein. 3. The silkworm has many mutants in which the size and pattern of the egg are modified. Morphological and biochemical analyses of some of such mutants revealed that the follicular epithelial cells have key roles in determining the egg characters. The results provide an approach to understanding the complex process of oogenesis. Less