Scolnick E M, Maryak J M, Parks W P
J Virol. 1974 Dec;14(6):1435-44. doi: 10.1128/JVI.14.6.1435-1444.1974.
DNA transcripts from V-NRK and RT21c rat type-C viruses were found to differ in their sequence homology to Kirsten and Harvey sarcoma viruses. V-NRK DNA transcripts consistently had homology to Kirsten and Harvey sarcoma virus, whereas RT21c DNA transcripts did not. To explain the differences, the nucleic acids and structural proteins of the two type-C viruses, released from each of two cell lines derived from Osborne-Mendel rats, were analyzed by molecular hybridization and competition radioimmunoassays. The p30 and p12 structural proteins of the two viruses were found to be highly related immunologically. In the V-NRK virus preparation, two sets of distinct RNA sequences were found in approximately equal amounts. One set is homologous to Ki-SV, and the other homologous to RT21c. In contrast, the RT21c virus preparation was found to contain a different ratio of these sequences. In this case the RT21c-like RNA sequences are present in 100-fold excess as compared to the additional Ki-SV specific sequences. Both NRK and RT21c cells contain in their DNA the full complement of Ki-SV homologous sequences, but NRK cells express much higher levels of these Ki-SV sequences in their RNA. These additional sequences, not homologous to RT21c, which are detected in uninfected NRK cellular RNA or V-NRK rat virus, could also be detected in the 60-70S RNA from a Moloney mouse type-C virus released from the NRK cells infected with the Moloney type-C virus. The results suggest that type-C viruses released from NRK cells incorporate species of RNA present in NRK cells which are homologous to Kirsten and Harvey sarcoma viruses. Either these sequences are of cellular origin, or rat cells contain two endogenous viruses with completely distinct nucleic acid sequences.
已发现来自V-NRK和RT21c大鼠C型病毒的DNA转录本与柯斯顿和哈维肉瘤病毒的序列同源性存在差异。V-NRK DNA转录本始终与柯斯顿和哈维肉瘤病毒具有同源性，而RT21c DNA转录本则不然。为了解释这些差异，通过分子杂交和竞争放射免疫测定法分析了从奥斯本-孟德尔大鼠来源的两种细胞系中释放的两种C型病毒的核酸和结构蛋白。发现这两种病毒的p30和p12结构蛋白在免疫学上高度相关。在V-NRK病毒制剂中，发现了两组数量大致相等的不同RNA序列。一组与Ki-SV同源，另一组与RT21c同源。相比之下，发现RT21c病毒制剂中这些序列的比例不同。在这种情况下，与额外的Ki-SV特异性序列相比，RT21c样RNA序列的含量多出100倍。NRK和RT21c细胞的DNA中都含有完整的Ki-SV同源序列，但NRK细胞在其RNA中表达的这些Ki-SV序列水平要高得多。这些在未感染的NRK细胞RNA或V-NRK大鼠病毒中检测到的、与RT21c不同源的额外序列，也可以在感染莫洛尼C型病毒的NRK细胞释放的莫洛尼小鼠C型病毒的60-70S RNA中检测到。结果表明，从NRK细胞释放的C型病毒包含NRK细胞中存在的与柯斯顿和哈维肉瘤病毒同源的RNA种类。这些序列要么是细胞起源的，要么大鼠细胞含有两种核酸序列完全不同的内源性病毒。
