Kuff E L, Ferdinand F J, Khoury G
J Virol. 1978 Jan;25(1):28-36. doi: 10.1128/JVI.25.1.28-36.1978.
Viral transcriptional complexes were extracted from the nuclei of monkey kidney cells infected with wild-type simian virus 40 (SV40) or a variant strain containing a high proportion of host-substituted DNA molecules. The RNAs synthesized by these complexes in an in vitro system were analyzed for their content of SV40 and host sequences by a technique of sequential hybridization to plaque-purified and substituted viral DNAs. The relative labeling of the two types of sequences was commensurate with their proportion in the viral DNA (about 20% host). The substituted virus contains both reiterated and unique types of cellular sequences, and both kinds appeared to be transcribed. Transcripts of the substituted sequences formed a much smaller proportion of the virus related RNA recovered from intact infected cells, suggesting that host sequence transcripts are synthesized but rapidly degraded in the whole cell. The alternative, that transcription of these sequences is artificially enhanced in the in vitro system, cannot be rigorously excluded. We compared the self-annealing of viral RNAs from nuclear extracts of cells infected with wild-type and substituted viruses; transcripts labeled both in vivo and in vitro showed a two- to threefold-higher level of self-annealing in the case of the variant than in the case of wild type SV40.
从感染野生型猴病毒40（SV40）或含有高比例宿主取代DNA分子的变异株的猴肾细胞核中提取病毒转录复合物。通过与噬菌斑纯化和取代的病毒DNA进行连续杂交的技术，分析这些复合物在体外系统中合成的RNA的SV40和宿主序列含量。两种类型序列的相对标记与其在病毒DNA中的比例（约20%宿主）相当。取代病毒包含重复和独特类型的细胞序列，且这两种序列似乎都被转录。从完整感染细胞中回收的与病毒相关的RNA中，取代序列的转录本所占比例要小得多，这表明宿主序列转录本在全细胞中合成但迅速降解。另一种可能性，即这些序列的转录在体外系统中被人为增强，无法被严格排除。我们比较了感染野生型和取代病毒的细胞的核提取物中病毒RNA的自我退火情况；在体内和体外标记的转录本显示，变异株的自我退火水平比野生型SV40高出两到三倍。
