Zaboĭkin M M, Likhtenshteĭn A V, Shapot V S
Biokhimiia. 1987 May;52(5):794-805.
Nuclear RNAs release from nucleoproteins of isolated nuclei absorbed on a celite column in a wide range of dissociating conditions (from 1 M LiCl--2 M urea at 2 degrees C to 4 M LiCl--8 M urea at 70-80 degrees C) was demonstrated. Such a high "adhesive" heterogeneity of nuclear RNAs (i.e., variations in the tightness of RNA-protein bonds) appears to be due to the association of nuclear matrix proteins. A direct correlation was found to exist between the metabolic turnover of RNA and the tightness of its association with the nuclear matrix. Actually, the pulse label which rapidly incorporates into the RNAt greater than 50 degrees, the RNA fraction being most tenaciously bound to the matrix, could be chased later into RNAs weakly bound to it. As the RNA-matrix binding weakens, the metabolic and structural properties of a given RNA change, e.g., sedimentation coefficients decrease, while the poly(A)+-RNA content and stability increase. The "adhesive" heterogeneity was found to be inherent in not only nuclear RNAs but also in cytoplasmic non-ribosomal RNAs, showing the same correlation, i.e., the tighter the RNA--protein complex, the higher the rate of RNA turnover. Cytoplasmic RNAs which differ in their adhesiveness may fulfil various intracellular functions, since polyribosomal mRNPs and informosomal mRNPs appear to be enriched in tightly and weakly bound RNA fractions, respectively. The interrelationships between nuclear and cytoplasmic RNAs are discussed.
已证实在广泛的解离条件下（从2℃时1M LiCl - 2M尿素到70 - 80℃时4M LiCl - 8M尿素），从吸附在硅藻土柱上的分离细胞核的核蛋白中释放出核RNA。核RNA这种高度的“黏附性”异质性（即RNA - 蛋白质键紧密程度的变化）似乎是由于核基质蛋白的缔合所致。发现RNA的代谢周转与其与核基质缔合的紧密程度之间存在直接相关性。实际上，快速掺入大于50℃的RNAt中的脉冲标记，即与基质结合最紧密的RNA部分，随后可被追踪到与基质结合较弱的RNA中。随着RNA - 基质结合减弱，特定RNA的代谢和结构特性会发生变化，例如沉降系数降低，而poly(A)+ - RNA含量和稳定性增加。发现“黏附性”异质性不仅存在于核RNA中，也存在于细胞质非核糖体RNA中，表现出相同的相关性，即RNA - 蛋白质复合物越紧密，RNA周转速率越高。黏附性不同的细胞质RNA可能履行各种细胞内功能，因为多核糖体mRNP和信息体mRNP似乎分别在紧密结合和弱结合的RNA部分中富集。本文讨论了核RNA与细胞质RNA之间的相互关系。
