Galau G A, Klein W H, Davis M M, Wold B J, Britten R J, Davidson E H
Cell. 1976 Apr;7(4):487-505. doi: 10.1016/0092-8674(76)90200-2.
Structural gene sequences active in a variety of sea urchin adult and embryo tissues are compared. A single-copy 3H-DNA fraction, termed mDNA, was isolated, which contains sequences complementary to the messenger RNA present on gastrula stage polysomes. Gastrula message sequences are 50 fold concentrated in the mDNA compared to total single-copy DNA. mDNA reactions were carried out with excess mRNA from blastula, pluteus, exogastrula, adult ovary, tubefoot, intestine, and coelomocytes, and with excess total mature oocyte RNA. A single-copy 3H-DNA fraction totally devoid of gastrula message sequences, termed null mDNA, was also reacted with these RNAs. Large differences in the extent of both mDNA and null mDNA reaction with the various RNAs were observed, indicating that in each state of differention a distinct set of structural genes is active, generally characterized by several thousand specific sequences. The complexity of gastrula mRNA was shown in previous work to be about 17 X 10(6) nucleotides. In units of 10(6) nucleotides, the complexities of the RNA sequence reacting with mDNA and with null mDNA in each tissue are, respectively, as follows: intestine mRNA: 2.1 and 3.7; coelomocyte mRNA: 3.5 and less than or equal to 1.4; tubefoot mRNA: 2.7 and less than or equal to 0.4; ovary mRNA: 13 and 6.7; oocyte total RNA: 17 and 20; blastula mRNA: 12 and 15; pluteus mRNA: 14 and less than or equal to 0.6; exogastrula mRNA: 14 and less than or equal to 0.6. The total complexity of each mRNA polulation is the sum of these values, as verified for several cases by reactions with total single-copy DNA. A relatively small set of mRNAs, the complexity of which is about 2.1 X 10(6) nucleotides, appears to be shared by several of the tissues studied.
对在多种海胆成体和胚胎组织中活跃的结构基因序列进行了比较。分离出了一个单拷贝的3H-DNA组分，称为mDNA，它包含与原肠胚期多聚核糖体上存在的信使RNA互补的序列。与总的单拷贝DNA相比，原肠胚信使序列在mDNA中浓缩了50倍。用来自囊胚、长腕幼虫、外原肠胚、成体卵巢、管足、肠道和体腔细胞的过量信使RNA，以及过量的成熟卵母细胞总RNA进行mDNA反应。还使一个完全不含原肠胚信使序列的单拷贝3H-DNA组分，称为无效mDNA，与这些RNA进行反应。观察到mDNA和无效mDNA与各种RNA反应程度的巨大差异，表明在每个分化状态下，都有一组独特的结构基因是活跃的，通常以数千个特定序列为特征。在先前的工作中已表明原肠胚信使RNA的复杂性约为17×10⁶个核苷酸。以10⁶个核苷酸为单位，在每个组织中与mDNA和无效mDNA反应的RNA序列的复杂性分别如下：肠道信使RNA：2.1和3.7；体腔细胞信使RNA：3.5和小于或等于1.4；管足信使RNA：2.7和小于或等于0.4；卵巢信使RNA：13和6.7；卵母细胞总RNA：17和20；囊胚信使RNA：12和15；长腕幼虫信使RNA：14和小于或等于0.6；外原肠胚信使RNA：14和小于或等于0.6。每个信使RNA群体的总复杂性是这些值的总和，在几个案例中通过与总的单拷贝DNA反应得到了验证。一组相对较小的信使RNA，其复杂性约为2.1×10⁶个核苷酸，似乎为所研究的几个组织所共有。
