Duration of the first steps of the human rRNA processing
Duration of the first steps of the human rRNA processing
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DOI：
10.4161/nucl.23985
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发表时间：
2013-03-01
期刊：
影响因子：
3.7
通讯作者：
Raska, Ivan
中科院分区：
文献类型：
--
作者：
Popov, Alexey;Smirnov, Evgeny;Raska, Ivan
哺乳动物细胞中rRNA的加工包括一系列初级47 S转录物的裂解，并导致产生三种rRNA：18 S，28 S和5.8S。人类细胞中主要处理事件的顺序已经确定，但对这一过程的动力学，特别是其早期阶段的动力学知之甚少。在本研究中，我们使用实时PCR来测量用放线菌素D抑制转录后的pre-rRNA水平。因此，我们可以估计rRNA转录物在两种人源性细胞系HeLa和LEP（人胚胎成纤维细胞）以及小鼠NIH 3 T3细胞中的半衰期。初级转录物在人细胞中似乎比在鼠细胞中更稳定。值得注意的是，所有情况下的图都显示出或多或少明显的滞后期，这可能反映了前体rRNA第一次切割之前的准备事件。此外，我们跟踪了5ETS片段的衰变动力学，该片段仅在41 S rRNA形成后降解。根据我们的估计，人类细胞中相应的三（或四）个处理步骤需要五到八分钟。
Processing of rRNA in mammalian cells includes a series of cleavages of the primary 47S transcript and results in producing three rRNAs: 18S, 28S and 5.8S. The sequence of the main processing events in human cells has been established, but little is yet known about the dynamics of this process, especially the dynamics of its early stages. In the present study, we used real-time PCR to measure levels of pre-rRNA after inhibition of transcription with actinomycin D. Thus we could estimate the half-life time of rRNA transcripts in two human-derived cell lines, HeLa and LEP (human embryonic fibroblasts), as well as in mouse NIH 3T3 cells. The primary transcripts seemed to be more stable in the human than in the murine cells. Remarkably, the graphs in all cases showed more or less pronounced lag phase, which may reflect preparatory events preceding the first cleavage of the pre-rRNA. Additionally, we followed the dynamics of the decay of the 5ETS fragment which is degraded only after the formation of 41S rRNA. According to our estimates, the corresponding three (or four) steps of the processing in human cells take five to eight minutes.