Cervera J, Martínez A, Renau-Piqueras J
J Ultrastruct Res. 1984 Jan;86(1):46-56. doi: 10.1016/s0022-5320(84)90094-7.
Methylation of nucleolar RNA was studied by autoradiography in HeLa cells using L-[methyl-3H]methionine and S-adenosyl-L-[methyl-3H]methionine as radioactive precursors. Pulse-labeling experiments show that nucleolar RNA methylation occurs on the newly synthesized RNA at the nucleolar fibrillar RNP component and mostly on the fibrillar ring of fibrillar centers, where pre-rRNA is being synthesized. Pulse-chase experiments show a shift of silver grains from the nucleolar fibrillar RNP component to the nucleolar granular component first and then to the cytoplasm. Labeling of nucleolar RNA via specific methylation permits the study of intranucleolar processing of pre-rRNA and confirms the sequence of labeling of the two nucleolar RNP components observed with radioactive uridine.
利用L-[甲基-³H]甲硫氨酸和S-腺苷-L-[甲基-³H]甲硫氨酸作为放射性前体，通过放射自显影术在HeLa细胞中研究核仁RNA的甲基化。脉冲标记实验表明，核仁RNA甲基化发生在核仁纤维状核糖核蛋白（RNP）组分上新合成的RNA上，且主要发生在纤维中心的纤维环上，而前体核糖体RNA（pre-rRNA）正是在该位置合成。脉冲追踪实验表明，银颗粒首先从核仁纤维状RNP组分转移到核仁颗粒组分，然后再转移到细胞质中。通过特异性甲基化对核仁RNA进行标记，有助于研究pre-rRNA在核仁内的加工过程，并证实了用放射性尿苷观察到的两种核仁RNP组分的标记顺序。
