Kleene K C
Biochem J. 1986 Feb 1;233(3):905-8. doi: 10.1042/bj2330905.
The equations that have been used previously to analyse the rate of decay of hnRNA implicitly assume that nascent hnRNAs are degraded stochastically. This assumption is inconsistent with electron-microscopic studies of transcription cited here, which show that nascent hnRNAs are not degraded during transcription, implying that hnRNA degradation occurs only after termination of transcription and release of the hnRNA from chromatin. Equations are derived describing the accumulation of radioactivity hnRNA during continuous labelling assuming that nascent hnRNAs are stable and that hnRNAs decay with first-order kinetics only after completion of transcription. The effects of the transient stability of nascent hnRNAs on the kinetics of hnRNA turnover can become important when the half-life of the hnRNA is shorter than the time to transcribe an hnRNA from the point of initiation to the point of termination. These equations should prove useful in studies of hnRNA turnover that require a precise description of the labelling kinetics of nascent and completed subpopulations of hnRNA.
先前用于分析核内不均一RNA（hnRNA）衰变速率的方程隐含地假定新生hnRNA是随机降解的。这一假设与本文引用的转录电子显微镜研究结果不一致，该研究表明新生hnRNA在转录过程中不会降解，这意味着hnRNA降解仅发生在转录终止以及hnRNA从染色质释放之后。推导了描述连续标记期间放射性hnRNA积累的方程，假定新生hnRNA是稳定的，并且hnRNA仅在转录完成后以一级动力学衰变。当hnRNA的半衰期短于从起始点到终止点转录一个hnRNA所需的时间时，新生hnRNA的瞬时稳定性对hnRNA周转动力学的影响可能变得很重要。这些方程在需要精确描述新生和完整hnRNA亚群标记动力学的hnRNA周转研究中应会证明是有用的。
