Recent advances in fluorescence microscopy have made it possible to measure the fluctuations of nascent (actively transcribed) RNA. These closely reflect transcription kinetics, as opposed to conventional measurements of mature (cellular) RNA, whose kinetics is affected by additional processes downstream of transcription. Here, we formulate a stochastic model which describes promoter switching, initiation, elongation, premature detachment, pausing, and termination while being analytically tractable. We derive exact closed-form expressions for the mean and variance of nascent RNA fluctuations on gene segments, as well as of total nascent RNA on a gene. We also obtain exact expressions for the first two moments of mature RNA fluctuations and approximate distributions for total numbers of nascent and mature RNA. Our results, which are verified by stochastic simulation, uncover the explicit dependence of the statistics of both types of RNA on transcriptional parameters and potentially provide a means to estimate parameter values from experimental data.

中文翻译：

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转录起始、延伸、暂停和终止随机模型中新生和成熟 RNA 波动的统计

荧光显微镜的最新进展使测量新生（主动转录）RNA 的波动成为可能。这些密切反映转录动力学，而不是成熟（细胞）RNA 的常规测量，其动力学受转录下游其他过程的影响。在这里，我们制定了一个随机模型，该模型描述了启动子转换、启动、延伸、过早脱离、暂停和终止，同时在分析上易于处理。我们推导出基因片段上新生 RNA 波动的均值和方差以及基因上总新生 RNA 的均值和方差的精确闭式表达式。我们还获得了成熟 RNA 波动的前两个时刻的精确表达式以及新生和成熟 RNA 总数的近似分布。我们的结果，