Ruben M, Bacchetti S, Graham F
Nature. 1983 Jan 13;301(5896):172-4. doi: 10.1038/301172a0.
The genome of adenoviruses is a double-stranded linear DNA molecule with inverted terminal repeats about 100 base pairs (bp) in length and a terminal protein covalently linked to the 5' nucleotide of each strand. Both of these features permit the formation of DNA circles, the inverted repeats allowing the circularization of single-stranded DNA and the terminal protein the joining of one or more molecules to yield double-stranded circles or concatemers. However, although the existence of covalently closed circles has been postulated, double-stranded viral DNA purified from virions or infected cells by conventional methods (that is, using proteases and phenol or chloroform) has always been obtained in a linear form. Here, we present evidence for the existence in adenovirus 5 (Ad5) infected cells of novel structures resulting from covalent head-to-tail joining of viral DNA molecules and show that these structures are due at least in part to the formation of covalently closed circles.
腺病毒的基因组是一个双链线性DNA分子，具有长度约为100个碱基对（bp）的反向末端重复序列，以及一个与每条链的5'核苷酸共价连接的末端蛋白。这两个特征都允许形成DNA环，反向重复序列允许单链DNA环化，而末端蛋白则使一个或多个分子连接以产生双链环或多联体。然而，尽管已经假定存在共价闭合环，但通过常规方法（即使用蛋白酶和苯酚或氯仿）从病毒粒子或感染细胞中纯化的双链病毒DNA一直以线性形式获得。在这里，我们提供证据表明在腺病毒5（Ad5）感染的细胞中存在由病毒DNA分子的共价头尾连接产生的新结构，并表明这些结构至少部分是由于共价闭合环的形成。
