Hruska J F, Clayton D A, Rubenstein J L, Robinson W S
J Virol. 1977 Feb;21(2):666-72. doi: 10.1128/JVI.21.2.666-672.1977.
DNA isolated from the hepatitis B antigen form known as the Dane particle was examined by electron microscopy before and after the endogenous Dane particle DNA polymerase reaction. The most frequently occurring form was an untwisted circular double-stranded DNA molecule approximately 1 mum in length. Less frequently occurring forms included circular DNA of approximately unit length and having one or more small single-stranded regions, similar circular molecules with one or more tails either shorter or longer than 1 mum in length, and very small circular molecules with tails. There was no increase in frequency or length of tails after a DNA polymerase reaction, suggesting that tails were not formed during this reaction. The mean length of circular molecules increased by 23% when DNA was spread in formamide compared with aqueous spreading, suggesting that single-stranded regions are present in most of the molecules. The mean length of circular molecules obtained from aqueous spreading increased by 27% after a Dane particle DNA polymerase reaction. This indicates that single-stranded regions were converted to double-stranded DNA during the reaction.
在进行内源性Dane颗粒DNA聚合酶反应之前和之后，通过电子显微镜检查了从被称为Dane颗粒的乙型肝炎抗原形式中分离出的DNA。最常见的形式是一种长度约为1微米的未扭曲环状双链DNA分子。较少出现的形式包括大约单位长度且有一个或多个小单链区域的环状DNA、具有一条或多条长度短于或长于1微米的尾巴的类似环状分子，以及带有尾巴的非常小的环状分子。DNA聚合酶反应后，尾巴的频率或长度没有增加，这表明在该反应过程中没有形成尾巴。与在水溶液中铺展相比，当DNA在甲酰胺中铺展时，环状分子的平均长度增加了23%，这表明大多数分子中存在单链区域。在进行Dane颗粒DNA聚合酶反应后，从水溶液铺展中获得的环状分子的平均长度增加了27%。这表明在反应过程中，单链区域被转化为双链DNA。
