Kamen R, Shure H
Cell. 1976 Mar;7(3):361-71. doi: 10.1016/0092-8674(76)90165-3.
The different species of polyoma virus-spedific RNA molecules present in the cytoplasm of 3T6 cells 30 hr after viral infection have been characterized by molecular hybridization between nonradioactive polyadenlated RNA, fractionated by sedimentation through sucrose-formamide density gradients, and the 32P-labeled separated strands of restriction endonuclease fragments of polyoma DNA. Two relatively abundant RNA molecules, sedimenting at 16S and at 19S, transcribed from the L strand of the viral DNA, as well as a minor 20S species transcribed from the E strand of the DNA, were detected. The most abundant viral transcript, the 16S RNA molecule, was estimated to be complementary to the 22% of the L-strand DNA extending from 47 to 25 map units. The less abundant 19S L DNA strand transcript included all the sequences present in the 16S RNA and mapped between 68 and 25 map units. The minor 20S RNA molecule was tentatively identified as a transcript of the E-strand DNA from the entire early region of the polyoma genome. These three viral RNA molecules together exhaust greater than 95% of the coding capacity of the viral DNA. A small region of the DNA (4-5%), including the origin of DNA replication, does not appear to determine sequences present among the major stable species of vital mRNA.
在病毒感染30小时后，通过蔗糖-甲酰胺密度梯度沉降分级分离的非放射性多聚腺苷酸化RNA与多瘤病毒DNA限制性内切酶片段的32P标记单链之间的分子杂交，对3T6细胞胞质中存在的不同种类的多瘤病毒特异性RNA分子进行了表征。检测到两个相对丰富的RNA分子，沉降系数分别为16S和19S，它们由病毒DNA的L链转录而来，还有一个由DNA的E链转录而来的较小的20S种类。最丰富的病毒转录本，即16S RNA分子，估计与从47到25图谱单位延伸的L链DNA的22%互补。较不丰富的19S L DNA链转录本包含16S RNA中存在的所有序列，定位在68到25图谱单位之间。较小的20S RNA分子初步被鉴定为来自多瘤病毒基因组整个早期区域的E链DNA转录本。这三种病毒RNA分子一起耗尽了病毒DNA编码能力的95%以上。DNA的一个小区域（4-5%），包括DNA复制起点，似乎并未决定重要mRNA主要稳定种类中的序列。
