Gene expression and its control agents in embryogenesis of Bombyxmori

建立了从家蚕卵中提取可翻译信使RNA的方法。用后一种方法可以明确作为基因表达研究标志的醛缩酶同工酶的切换方式。基于建立人类计划，即以人类全基因组测序为目标，提出了家蚕基因文库和基因组文库的制备范围。针对主要的蛋黄蛋白--鸡蛋特异蛋白(ESP)，对其转录、翻译和翻译后加工进行了详细的分析。此外，卵黄蛋白的利用方式已经开始被发现，发现了一种能降解ESP的特定蛋白酶。这种酶表现出ESP链的有限断裂。这提供了在分子水平上对卵黄蛋白利用的初始步骤的第一个了解。卵巢蜕皮类固醇的存在已为人所知。主要种类为结合型，…更多的可能是本研究中检测到的储存形式和水解酶可能在胚胎发育过程中发挥关键作用，提供自由的、从而具有活性的蜕皮类固醇。家蚕滞育的启动受单基因PND^+控制。经双向凝胶电泳法分析，后者的产物为一种蛋白质。从蛋白质合成和RNA合成两个方面讨论了后一个基因(及其产物)在滞育开始时的作用方式。关于滞育的打破，已发现所谓滞育发育结束的信号是酯酶A的激活，该酶被结晶，并被证明是一个在特定条件下在体外激活自身的计时分子，极小地抑制了家蚕滞育卵的冷激活。核苷酸碱基，特别是5-甲基胞嘧啶，改变了蚕卵的冬眠程序。这些试剂可能作为方便的实验药物，扰乱待分析的滞育系统。较少

The method for extraction of translatable messenger RNA from the eggs of Bombyx mori was established. By using the latter method the mode of switchover of aldolase isozymes, chosen as a marker for gene expression study, could be clarified. Based on the effort to set up the human project, i.e. aiming at the sequencing of the whole genome of man, the scope of preparing the cDNA and genomic libraries of the silkworm was proposed. As to the major yolk protein named egg specific protein (ESP), the relevant transcription, translation and posttranslational processing were precisely analyzed. Moreover, the way of yolkprotein utilization has begun to be uncovered; a specific protease which can degrade ESP was found to be present. This enzyme exhibit a limited break of the ESP chain. This provides the first understanding of the initial steps of yolk protein utilization at the molecular level. The presence of ovarian ecdysteroids has been known. The major species were found to be conjugate types, … More which may be the storage forms and hydrolysis enzymes detected in the present study might have critical roles to provide free, thus active, ecdysteroids during embryogenesis. The initiation of diapause in B. mori is known to be controlled by a single gene pnd^+. The product of the latter gene was suggested to be a protein as separated by two-dimensional gel electrophoresis. The mode of action of the latter gene (and its product) was discussed in terms of protein synthesis and RNA synthesis at the period of diapause onset. As to the break of diapause a signal of the end of the so-called diapause development has been found to be the activation of esterase A. This enzyme was crystallized and revealed to be a time-measuring molecule which activates itself in vitro under the specified conditions minicking the cold activation of diapausing eggs of the silkworm. The nucleotide bases in particular 5-methylcytosine changed the hibernating program of the silkworm eggs. These agents might serve as convenient experimental drugs that disturb the diapasue system to be analyzed. Less