BIOSYNTHESIS AND UTILIZATION OF EXTENSIVELY UNDER-METHYLATED POLY(A)+ RNA IN CHO CELLS DURING A CYCLOLEUCINE TREATMENT
BIOSYNTHESIS AND UTILIZATION OF EXTENSIVELY UNDER-METHYLATED POLY(A)+ RNA IN CHO CELLS DURING A CYCLOLEUCINE TREATMENT
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DOI：
10.1093/nar/5.8.2927
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发表时间：
1978-01-01
影响因子：
14.9
通讯作者：
CABOCHE, M
中科院分区：
文献类型：
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作者：
BACHELLERIE, JP;AMALRIC, F;CABOCHE, M
通过对S-腺苷甲硫氨酸介导甲基化的特异性抑制剂环亮氨酸（cycloleucine）的有效体内作用研究，探讨了RNA甲基化在mRNA成熟和掺入多聚体中的控制作用.在环亮氨酸处理过程中，hnRNA的生物合成速率及其随后的多聚腺苷酸化与未处理的细胞相比仅略有降低.然而，观察到poly（A）+甲基化不足分子的细胞质外观中的显著滞后时间，与hnRNA的平均大小向更高分子量的瞬时转变平行。然而，在长追踪时间（3 h）后，脉冲标记的poly（A）+mRNA转移到细胞质的总量增加。对于环亮氨酸处理的细胞和对照细胞两者来说是近似相同的。具有5 '末端帽的广泛甲基化不足的poly（A）+细胞质RNA以与对照信使分子非常相似的比例掺入多聚核糖体中。这些结果表明，正常水平的甲基化对于功能mRNA分子的产生并不是严格需要的，尽管它似乎对成熟过程的动力学很重要。
The role of RNA methylations in the control of mRNA maturation and incorporation into polysomes has been investigated through a study of the effectsin vivoof cycloleucine, a specific inhibitor of S-adenosyl-methionine mediat methylation.During the cycloleucine treatment, the rate of biosynthesis of hnRNA and its subsequent polyadenylation were only slightly reduced as compared with untreated cells. However a significant lag-time in the cytoplasmic appearance of poly(A)+undermethylated molecules was observed, in parallel with a transient shift in the average size of hnRNA towards higher molecular weight. Nevertheless, the total amount of pulse-labelled poly(A)+mRNA transferred to cytoplasm after a long chase time (3 h.) was approximatively the same for both cycloleucine-treated and control cells. Extensively undermethy- lated poly(A)+cytoplasmic RNAs, possessing a 5′ terminal cap were incorpo rated into polysomes in proportions very similar to control messenger molecules.These results suggest that a normal level of methylation is not stringently required for the production of functional mRNA molecules although it appears to be of importance for the kinetics of the maturational process.