Kleene K C, Humphreys T
J Embryol Exp Morphol. 1985 Feb;85:131-49.
We studied the sequences transcribed in the rare class of hnRNA and the rare maternal RNA set in blastula embryos and a tissue of adult sea urchins, coelomocytes. About 26% of labelled single-copy DNA formed hybrids which bound to hydroxyapatite after three cycles of hybridization with nuclear RNA from blastulae and coelomocytes. This corresponds to transcription of about 50% of the single-copy genome by both cell populations. To compare the rare hnRNA sequences synthesized by blastulae and coelomocytes directly, labelled single-copy DNA was hybridized with blastula nuclear RNA to high RNA C0t, fractionated into sequences complementary and non-complementary to blastula nuclear RNA by chromotography on hydroxyapatite, and then each fraction was rehybridized with nuclear RNA from blastulae and coelomocytes. About 62% of the labelled DNA complementary to blastula nuclear RNA and about 1.5% of the labelled DNA non-complementary to blastula nuclear RNA hybridized with nuclear RNA from both cell populations. Thus, coelomocytes and blastula embryos transcribe essentially the same single-copy sequences in the rare hnRNA class. A probe for the rare maternal RNA set was isolated by hybridizing single-copy DNA with total egg RNA to high RNA C0t. 65-67% of this probe hybridized with whole-cell RNA from eggs, blastulae, plutei and coelomocytes demonstrating that essentially all rare maternal RNAs are present, and presumably transcribed, in blastulae, plutei and coelomocytes.
我们研究了囊胚胚胎以及成年海胆的一种组织——体腔细胞中，在稀有类别的核内不均一RNA（hnRNA）和稀有母源RNA集合中所转录的序列。在用囊胚和体腔细胞的核RNA进行三轮杂交后，约26%的标记单拷贝DNA形成了与羟基磷灰石结合的杂交体。这相当于两个细胞群体转录了约50%的单拷贝基因组。为了直接比较囊胚和体腔细胞合成的稀有hnRNA序列，将标记的单拷贝DNA与囊胚核RNA杂交至高RNA C0t值，通过羟基磷灰石柱层析分离成与囊胚核RNA互补和非互补的序列，然后将每个组分再与囊胚和体腔细胞的核RNA杂交。与囊胚核RNA互补的标记DNA中约62%，以及与囊胚核RNA非互补的标记DNA中约1.5%，与两个细胞群体的核RNA杂交。因此，体腔细胞和囊胚胚胎在稀有hnRNA类别中转录基本相同的单拷贝序列。通过将单拷贝DNA与全卵RNA杂交至高RNA C0t值，分离出了稀有母源RNA集合的探针。该探针的65 - 67%与卵、囊胚、幼体和体腔细胞的全细胞RNA杂交，表明基本上所有稀有母源RNA都存在于囊胚、幼体和体腔细胞中，并且推测是在这些细胞中进行转录的。
