May E, Kress M, May P
Nucleic Acids Res. 1978 Sep;5(9):3083-99. doi: 10.1093/nar/5.9.3083.
Using in vitro translation of sucrose-gradient fractionated cytoplasmic mRNA from SV40-infected cells, we have shown that a deletion in the region mapping between 0.54--0.59 reduced the size of mRNA for small-t but not the size of mRNA for large-T. Mutants with a deletion in this region were shown to produce in vivo either shortened small-t or no small-t, and normal large-T. Similarly, in vitro translation of poly(A)+cytoplasmic RNA from cells infected with these mutants gave the same results. On the other hand in vitro translation of poly(A)+nuclear RNA from the mutants which made no small-t produced a small-t derivative possibly synthesized from a prespliced RNA species. We have also shown that poly(A)+nuclear RNA from mutant dl 2122 produced two small-t related proteins: one of these (MW: 11K) probably represents the product of a "prespliced" RNA, the other (MW: 17K) which is also found in the cytoplasm represents the product of the mutant specific small-t mRNA.
利用从SV40感染细胞中经蔗糖梯度分级分离的细胞质mRNA进行体外翻译，我们发现，位于0.54 - 0.59之间区域的缺失减小了小t mRNA的大小，但并未减小大T mRNA的大小。已证明，该区域存在缺失的突变体在体内要么产生缩短的小t，要么不产生小t，但能产生正常的大T。同样，用这些突变体感染的细胞的聚腺苷酸加尾细胞质RNA进行体外翻译也得到了相同的结果。另一方面，从不产生小t的突变体的聚腺苷酸加尾核RNA进行体外翻译，产生了一种可能由前体剪接RNA物种合成的小t衍生物。我们还发现，突变体dl 2122的聚腺苷酸加尾核RNA产生了两种与小t相关的蛋白质：其中一种（分子量：11K）可能代表“前体剪接”RNA的产物，另一种（分子量：17K）也存在于细胞质中，代表突变体特异性小t mRNA的产物。
