EDSTROM J E, GRAMPP W, SCHOR N
J Biophys Biochem Cytol. 1961 Dec;11(3):549-57. doi: 10.1083/jcb.11.3.549.
A study has been made of the content and composition of RNA in cytoplasm, nucleoplasm, and nucleoli from growing oocytes of the starfish Asterias rubens. The determinations were carried out, using ultramicrochemical methods, on units isolated by microdissection from fixed sections. Macrochemical and interferometric control experiments show that RNA can be quantitatively evaluated in this way. The results show that the growing oocyte represents a system in which the relations between the quantities of nucleolar, nucleoplasmic, and cytoplasmic RNA undergo great changes. These changes are continuous for nucleolar and cytoplasmic RNA so that their amounts may be predicted from the size of the cell. Nucleoplasmic RNA, on the other hand, shows great variations among different cells, independent of cell size. Purine-pyrimidine analyses show that each cell component contains an RNA which differs significantly from that of the other two. Cytoplasmic and nucleolar RNA are closely related, the only difference being a slightly higher guanine/uracil quotient for the nucleolar RNA. They are both of the usual tissue RNA type, i.e., they show a preponderance of guanine and cytosine over adenine and uracil. Nucleoplasmic RNA deviates grossly from the RNA of the other two components. Here the concentrations of adenine and uracil are higher than those of guanine and cytosine, respectively. This RNA consequently shows some resemblance to the general type of animal DNA although the purine/pyrimidine ratio is far from unity. Our data favor a nucleolar origin for the stable part of the ribosomal RNA and a nucleoplasmic one for the unstable part (the messenger RNA).
对红海星生长中的卵母细胞的细胞质、核质和核仁中的RNA含量及组成进行了研究。采用超微化学方法,对从固定切片中通过显微切割分离出的单位进行了测定。宏观化学和干涉测量对照实验表明,RNA可以通过这种方式进行定量评估。结果表明,生长中的卵母细胞代表了一个系统,其中核仁、核质和细胞质RNA的数量关系发生了很大变化。核仁RNA和细胞质RNA的这些变化是连续的,因此它们的量可以根据细胞大小来预测。另一方面,核质RNA在不同细胞之间表现出很大差异,与细胞大小无关。嘌呤-嘧啶分析表明,每个细胞成分都含有一种与其他两种成分显著不同的RNA。细胞质RNA和核仁RNA密切相关,唯一的区别是核仁RNA的鸟嘌呤/尿嘧啶比值略高。它们都属于常见的组织RNA类型,即鸟嘌呤和胞嘧啶的含量高于腺嘌呤和尿嘧啶。核质RNA与其他两种成分的RNA有很大偏差。这里腺嘌呤和尿嘧啶的浓度分别高于鸟嘌呤和胞嘧啶。因此,这种RNA与动物DNA的一般类型有一些相似之处,尽管嘌呤/嘧啶比值远非1。我们的数据支持核糖体RNA的稳定部分起源于核仁,不稳定部分(信使RNA)起源于核质。