Hopper A K, Banks F
Cell. 1978 Jun;14(2):211-9. doi: 10.1016/0092-8674(78)90108-3.
It has been proposed that the conditional yeast mutant ts136 is defective in the transport of mRNA from the nucleus to the cytoplasm (Hutchinson, Hartwell and McLaughlin, 1969). We have examined ts136 to determine whether it is defective in tRNA biosynthesis. At the restrictive temperature, the mutant accumulates twelve new species of RNA. These species co-migrate on polyacrylamide gels with some of the pulse-labeled precursor tRNAs. Three of the new RNAs (species 1a, 1b and 1c are large enough to contain two tandom tRNAs. Although RNAs 1a, 1b, and 1c do not contain detectable levels of modified and methylated bases, at least one of them hybridizes to DNA from an E. coli plasmid containing a yeast tRNA gene. All the remaining RNAs (2--8) contain modified and methylated bases typical of tRNA. Three of these species were tested and were found to hybridize to tRNA genes. Ribosomal RNA synthesis is also defective in ts136. It is suggested that ts136 may be defective in a nucleolytic activity, which is a prerequisite to RNA transport.
有人提出，条件性酵母突变体ts136在mRNA从细胞核向细胞质的转运过程中存在缺陷（哈钦森、哈特韦尔和麦克劳克林，1969年）。我们对ts136进行了检测，以确定其在tRNA生物合成方面是否存在缺陷。在限制温度下，该突变体积累了12种新的RNA物种。这些物种在聚丙烯酰胺凝胶上与一些脉冲标记的前体tRNA共迁移。其中三种新RNA（1a、1b和1c物种）足够大，可包含两个串联的tRNA。尽管RNA 1a、1b和1c不含可检测水平的修饰碱基和甲基化碱基，但其中至少有一种与来自含有酵母tRNA基因的大肠杆菌质粒的DNA杂交。所有其余的RNA（2 - 8）都含有tRNA特有的修饰碱基和甲基化碱基。对其中三个物种进行了测试，发现它们可与tRNA基因杂交。ts136中的核糖体RNA合成也存在缺陷。有人认为，ts136可能在一种核酸酶活性方面存在缺陷，而这种活性是RNA转运的先决条件。
