Zieve G, Penman S
Cell. 1976 May;8(1):19-31. doi: 10.1016/0092-8674(76)90181-1.
The small molecular weight RNAs of the HeLa cell have been located in specific subcellular fractions. SnA is located in the nucleolus and is partially bonded to nucleolar 28S RNA. SnD, the most abundant of the small nuclear RNAs, is partially released from the nucleus when the nuclear preparation is briefly warmed. SnF is released from the nuclei when chromatin is digested with the micrococcal nuclease and not when pancreatic DNAase is used. The remainder of the small nuclear species remain in the nucleus following the digestion of chromatin and are concluded to be elements of the "nuclear skeleton." SnK is found predominantly in the cytoplasm, but migrates quantitatively to the nuclear fraction in the presence of high levels of actinomycin D. ScL is totally cytoplasmic and is partially bound to cell membranes. It is the 7S RNA found in oncornavirus virions. All the small nuclear RNAs appear initially in the cytoplasmic fraction before fixation in the nucleus. Two short-lived cytoplasmic species behave kinetically as precursors to the stable nuclear RNAs.
HeLa细胞的小分子RNA已定位在特定的亚细胞组分中。SnA位于核仁，部分与核仁28S RNA结合。SnD是最丰富的小核RNA，当核制剂短暂加热时，它会部分从细胞核中释放出来。当用微球菌核酸酶消化染色质时，SnF从细胞核中释放出来，而使用胰DNA酶时则不会。在染色质消化后，其余的小核RNA种类保留在细胞核中，被认为是“核骨架”的成分。SnK主要存在于细胞质中，但在高浓度放线菌素D存在下会定量迁移到核组分中。ScL完全位于细胞质中，部分与细胞膜结合。它是在肿瘤病毒粒子中发现的7S RNA。所有小核RNA在固定于细胞核之前最初都出现在细胞质组分中。两种短寿命的细胞质RNA在动力学上表现为稳定核RNA的前体。
