Qualitative and quantitative analyses of mRNAs in relation to embryogenesis of the silkworm, Bombyx mori.

利用体外翻译系统对mRNAs进行分析表明，家蚕卵在受精、滞育开始、滞育终止和胚胎发生过程中的质量变化很小。在显微注射蛋白质前体后，体内合成的蛋白质也得到了类似的结果。这些相当出人意料的观察表明，各自蛋白质的翻译后修饰可能在细胞分化中发挥关键作用。另一方面，发现一组HSP70蛋白类似物在热盐酸中浸泡后暂时表达，这种处理通常是为了打破家蚕卵的滞育。这些所谓的“应激蛋白”的诱导首次解释了为什么卵子不会受到热酸的严重伤害，并能经历非常正常的发育过程。接下来，我们对mRNAs所在的鸡蛋的大小感兴趣。卵的大小可以通过巨蛋、小蛋等突变来改变。我们研究了这些突变基因的表达方式，并通过激素处理来模仿它们的行为。血淋巴蛋白可能在卵子发生过程中被整合到卵子中，并可能影响mRNA的利用，也进行了研究。本研究结果可能有助于进一步发展现代生物学研究体系。

Analyses of mRNAs by using in vitro translation system showed that the eggs of Bombyx mori exhibited very small changes in terms of quality during fertilization, onset of diapause, termination of diapause and embryogenesis. Similar results were obtained when in vivo synthesized proteins were revealed after microinjection of protein precursors. these, rather unexpected observations indicate that the post-translational modification of respective proteins may have critical roles in cellular differentiation. On the other hand, a group of hsp70 protein analogs were found to be temporarily expressed after immersion in hot HCl, the treatment usually conducted for the silkworm eggs to break diapause. The induction of these so-called "stress proteins" for the first time explains the reason why the eggs are not seriously injured by the hot acid and can undergo very normal course of development. Next, we are interested in the size of the eggs where the mRNAs reside. The size of eggs can be changed by the mutations called Giant egg, small egg etc. The mode of expression of these mutant genes was investigated and their actions were mimicked by hormone treatment. The hemolymph proteins, which may be incorporated into eggs during oogenesis and possibly affect mRNA utilization, were also investigated. The present results may contribute to a further development of modern systems for biological study.