Standart N, Dale M, Stewart E, Hunt T
Department of Biochemistry, University of Cambridge, UK.
Genes Dev. 1990 Dec;4(12A):2157-68. doi: 10.1101/gad.4.12a.2157.
Clam oocytes display a striking difference in the pattern of protein synthesis on fertilization, which is maintained when cell-free extracts are assayed in the rabbit reticulocyte lysate. The mRNAs encoding ribonucleotide reductase and cyclin A (the major masked messages in the oocyte extracts) can be translationally activated by gel filtration in 0.5 M KCl, presumably by removal of repressor protein(s). When synthetic RNAs corresponding to different segments of ribonucleotide reductase and cyclin A mRNAs were added to oocyte extracts in 0.5 M KCl in a "competitive unmasking" assay, specific and complete unmasking of these mRNAs occurred on addition of antisense 3'-noncoding transcripts. The unmasking region in ribonucleotide reductase mRNA maps to a region of 134 nucleotides centered one-third of the way down the 3'-noncoding region.
蛤卵母细胞在受精时蛋白质合成模式上表现出显著差异，当在兔网织红细胞裂解物中检测无细胞提取物时，这种差异依然存在。编码核糖核苷酸还原酶和细胞周期蛋白A的mRNA（卵母细胞提取物中的主要隐蔽信息）可通过在0.5M KCl中进行凝胶过滤而被翻译激活，推测是通过去除阻遏蛋白实现的。在“竞争性去隐蔽”实验中，当将与核糖核苷酸还原酶和细胞周期蛋白A mRNA不同片段对应的合成RNA添加到0.5M KCl中的卵母细胞提取物中时，加入反义3'-非编码转录本后，这些mRNA会发生特异性且完全的去隐蔽。核糖核苷酸还原酶mRNA中的去隐蔽区域定位于一个134个核苷酸的区域，该区域位于3'-非编码区域向下三分之一处的中心位置。
