Humphries S, Windass J, Williamson R
Cell. 1976 Feb;7(2):267-77. doi: 10.1016/0092-8674(76)90026-x.
Using cDNA hybridization, mouse globin RNA sequences can be detected in the nuclear and cytoplasmic RNA not only from erythroid cells (fetal liver and reticulocytes), but also in low amounts in non-erythroid tissues (adult brain and liver, and cultured lymphoma, untransformed, and transformed fibroblast cell lines). For the nuclear RNAs, melting curve, density, and size determinations on the hybrids confirmed the presence of an RNA species indistinguishable by cDNA hybridization from reticulocyte globin mRNA. Thus the genes coding for alpha- and beta-globin, proteins thought to be found only in a restricted range of differentiated cell types, may nonetheless be transcribed at very low levels in all mouse cells. The proportion of the globin RNA sequences in the nuclear RNA that are found associated with poly(A) sequences does not vary markedly from one tissue or cell line to another. In erythroid cells, however, the proportion of the cellular globin RNA sequences that are found in the cytoplasm is very much higher than in non-erythroid cells. This suggests the existence of messenger-specific nuclear post-transcriptional control mechanisms which do not use poly(A) as a signal, and which allow the cytoplasmic accumulation of globin mRNA only in erythroid tissues.
利用cDNA杂交技术，不仅可以在红细胞（胎儿肝脏和网织红细胞）的核RNA和胞质RNA中检测到小鼠珠蛋白RNA序列，而且在非红细胞组织（成体脑和肝脏，以及培养的淋巴瘤、未转化和转化的成纤维细胞系）中也能检测到少量该序列。对于核RNA，对杂交体进行的熔解曲线、密度和大小测定证实，存在一种通过cDNA杂交与网织红细胞珠蛋白mRNA无法区分的RNA物种。因此，编码α和β珠蛋白的基因，虽然人们认为这些蛋白质仅在有限范围的分化细胞类型中存在，但在所有小鼠细胞中可能仍以极低水平转录。在核RNA中发现的与聚腺苷酸（poly(A)）序列相关的珠蛋白RNA序列比例，在不同组织或细胞系之间没有明显差异。然而，在红细胞中，细胞珠蛋白RNA序列在细胞质中的比例远高于非红细胞。这表明存在信使特异性的核转录后控制机制，这些机制不将poly(A)用作信号，并且仅在红细胞组织中允许珠蛋白mRNA在细胞质中积累。
