Tsai M J, Ting A C, Nordstrom J L, Zimmer W, O'Malley B W
Cell. 1980 Nov;22(1 Pt 1):219-30. doi: 10.1016/0092-8674(80)90170-1.
The existence of poly(A) sequences in the multiple high molecular weight forms of ovalbumin and ovomucoid nuclear RNA has been determined. The results indicate that all the bands observed in the total nuclear RNA including the largest (7.8 kb) were also detected in the poly(A) RNA. Kinetic labeling and chase experiments in oviduct tissue-suspension system indicated that the ovalbumin and ovomucoid high molecular weight RNAs which were labeled with a short-time incubation can be chased by cold nucleosides and actinomycin D into mature mRNAs. The largest RNAs labeled in this oviduct suspension system have a size of 7.8 kb for ovalbumin and 5.5 kb for ovomucoid, which correspond respectively to the "a" bands of steady state RNA. The processing of the precursors to mature mRNA was also examined by electron microscopic analysis, by hybridizing oviduct nuclear RNA to probes which were isolated from different segments of intervening DNA sequences and by measuring the turnover kinetics of specific intervening sequences present in cellular poly(A) RNA. The results indicate that the seven intervening sequence regions of the ovomucoid precursor are removed in a preferred but not necessarily an obligatory order.
已确定在卵清蛋白和卵类粘蛋白核RNA的多种高分子量形式中存在多聚（A）序列。结果表明，在包括最大的（7.8 kb）在内的总核RNA中观察到的所有条带，在多聚（A）RNA中也能检测到。在输卵管组织悬浮系统中的动力学标记和追踪实验表明，经短时间孵育标记的卵清蛋白和卵类粘蛋白高分子量RNA可被冷核苷和放线菌素D追踪为成熟的mRNA。在该输卵管悬浮系统中标记的最大RNA，卵清蛋白大小为7.8 kb，卵类粘蛋白为5.5 kb，分别对应于稳态RNA的“a”条带。还通过电子显微镜分析、使输卵管核RNA与从间隔DNA序列的不同片段分离的探针杂交以及测量细胞多聚（A）RNA中存在的特定间隔序列的周转动力学，来研究前体加工成成熟mRNA的过程。结果表明，卵类粘蛋白前体的七个间隔序列区域以一种优先但不一定是必须的顺序被去除。
