Battula N, Todaro G J
J Virol. 1980 Dec;36(3):709-18. doi: 10.1128/JVI.36.3.709-718.1980.
Three species of unintegrated viral DNAs were found in permissive cells infected with baboon type C virus. The major species was a 9.0-kilobase (kb) linear DNA that was infectious. A restriction endonuclease map of this DNA was constructed and oriented with respect to the viral RNA. The linear DNA had a 0.6-kb sequence repeated at each terminus. These terminal repeat sequences were required for infectivity of the viral DNA. The minor species of the unintegrated viral DNAs were covalently closed circles of 9.0 and 8.4 kb. The smaller circle was in two- to threefold excess over the larger circle. The difference appeared to be that the smaller circle lacked one of the two 0.6-kb repeat sequences found in the larger circle. Restriction endonuclease maps of the integrated viral DNAs were constructed, and the sequences on both viral DNA and cellular DNA that are involved in integration were determined. The integrated viral DNA map was identical to that of the unintegrated infectious 9.0-kb linear DNA. Therefore, a specific site in the terminal repeat sequence of the viral DNA was used to integrate with the host cell DNA. The sizes of the cellular DNA fragments were different from clone to clone but stable with cell passage. Therefore, many sites in the cell DNA can recombine with the viral DNA.
在感染狒狒C型病毒的允许细胞中发现了三种未整合的病毒DNA。主要种类是一种具有感染性的9.0千碱基（kb）线性DNA。构建了该DNA的限制性内切酶图谱，并相对于病毒RNA进行了定向。线性DNA在每个末端都有一个0.6 kb的序列重复。这些末端重复序列是病毒DNA感染性所必需的。未整合病毒DNA的次要种类是9.0 kb和8.4 kb的共价闭合环。较小的环比较大的环多出两到三倍。差异似乎在于较小的环缺少在较大环中发现的两个0.6 kb重复序列中的一个。构建了整合病毒DNA的限制性内切酶图谱，并确定了病毒DNA和细胞DNA中参与整合的序列。整合病毒DNA图谱与未整合感染性9.0 kb线性DNA的图谱相同。因此，病毒DNA末端重复序列中的一个特定位点用于与宿主细胞DNA整合。细胞DNA片段的大小因克隆而异，但随细胞传代稳定。因此，细胞DNA中的许多位点可以与病毒DNA重组。
