Haegeman G, Iserentant D, Gheysen D, Fiers W
Nucleic Acids Res. 1979 Dec 11;7(7):1799-814. doi: 10.1093/nar/7.7.1799.
d1-1811 is a viable SV40 mutant with a 40 base pair deletion that includes the major wild-type capping site of late mRNA at map position 0.72. The late viral mRNAs induced by d1-1811 have now been further characterized by inversed S1-mapping analysis. The S1-resistant, 32P-labeled RNA fragments derived from the leader region were examined by fingerprinting and by analysis of RNase T2-generated 5'-terminal cap structures. The results show that most if not all of the mutant leader fragments analyzed have their 5' terminus to the left of the d1-1811 deletion site, i.e., closer to the origin of DNA replication. The major altered leader fragment is a continuous transcript from the DNA in the region 0.716 to 0.761 map unit and its 5' terminus has been precisely mapped at nucleotide L290. The observation that the cap structure of the major altered leader is only a minor cap species in wild-type late RNA suggests regulation in the use of different capping sites in SV40.
d1-1811是一种可行的SV40突变体，有一个40个碱基对的缺失，该缺失包括位于图谱位置0.72处的晚期mRNA主要野生型加帽位点。现在通过反向S1图谱分析进一步表征了由d1-1811诱导的晚期病毒mRNA。通过指纹图谱分析以及对核糖核酸酶T2产生的5'-末端帽结构的分析，研究了来自前导区的S1抗性32P标记的RNA片段。结果表明，所分析的大多数（如果不是全部）突变体前导片段的5'末端位于d1-1811缺失位点的左侧，即更靠近DNA复制起点。主要改变的前导片段是从图谱单位0.716至0.761区域的DNA连续转录本，其5'末端已精确定位在核苷酸L290处。主要改变的前导序列的帽结构在野生型晚期RNA中只是一种次要的帽类型，这一观察结果表明SV40在不同加帽位点的使用上存在调控。
