中国仓鼠细胞中多聚腺苷酸化多核糖体和信息体信使核糖核酸的复杂性与多样性比较

Comparison of complexity and diversity of polyadenylated polysomal and informosomal messenger ribonucleic acid from Chinese hamster cells.

作者信息

Walters R A, Yandell P M, Enger M D

出版信息

Biochemistry. 1979 Sep 18;18(19):4254-61. doi: 10.1021/bi00586a034.

DOI:10.1021/bi00586a034

Abstract

The sequence complexity and relative abundance of cytoplasmic polyadenylated polysomal (ribosome-bound) mRNA and cytoplasmic polyadenylated informosomal (ribosome-free) mRNA were analyzed in exponentially growing Chinese hamster cells (line CHO) using the technique of cDNA hybridization to excess poly(A)+ mRNA. Polysomal and informosomal mRNAs had similar complexities ( approximately 8300 mRNA species), but both the fraction of mRNA and the number of sequences comprising the mRNA abundance classes were different. Heterologous annealing reactions showed that all of the mRNA sequences detected were shared by the polysomal and informosomal mRNAs. However, the most abundant informosomal mRNA component was considerably different from the most abundant polysomal mRNA component. For a more detailed analysis, cDNA complementary to the most abundant informosomal and polysomal mRNAs was isolated. By use of the fractionated cDNA, it could be demonstrated that the most abundant informosomal mRNA sequences were distributed in the polysomal mRNA with an approximately fivefold reduction in relative frequency. These results are not compatible with models postulating translational control of gene expression by the complete sequestering of some mRNA sequences in an untranslatable form in the cytoplasm. The data are, however, consistent with models encompassing differential rates of initiation on the polysome and/or preferential affinity of some mRNAs for initiation factors.

摘要

利用cDNA与过量多聚腺苷酸（poly(A)+）mRNA杂交技术，分析了指数生长期中国仓鼠细胞（CHO细胞系）中细胞质多聚腺苷酸化多核糖体（核糖体结合）mRNA和细胞质多聚腺苷酸化信息体（核糖体游离）mRNA的序列复杂性和相对丰度。多核糖体mRNA和信息体mRNA具有相似的复杂性（约8300种mRNA种类），但mRNA的比例以及构成mRNA丰度类别的序列数量均有所不同。异源退火反应表明，检测到的所有mRNA序列在多核糖体mRNA和信息体mRNA中均有共享。然而，最丰富的信息体mRNA成分与最丰富的多核糖体mRNA成分有很大差异。为了进行更详细的分析，分离了与最丰富的信息体mRNA和多核糖体mRNA互补的cDNA。通过使用分级分离的cDNA，可以证明最丰富的信息体mRNA序列以相对频率约降低五倍的形式分布在多核糖体mRNA中。这些结果与一些模型不相符，这些模型假定通过将一些mRNA序列以不可翻译的形式完全隔离在细胞质中来进行基因表达的翻译控制。然而，这些数据与包含多核糖体上起始速率差异和/或某些mRNA对起始因子的优先亲和力的模型一致。