Tamashiro J C, Filpula D, Friedmann T, Spector D H
J Virol. 1984 Nov;52(2):541-8. doi: 10.1128/JVI.52.2.541-548.1984.
The genome of human cytomegalovirus strain AD169 contains a region of heterogeneity located at the junction between the long (L) and short (S) components of the viral DNA. Twelve cloned L-S junction fragments were studied by using the restriction enzymes HaeII and XhoI. The region of heterogeneity was localized within a single HaeII restriction fragment. The enzyme XhoI was used to subdivide this region and revealed the presence of three types of heterogeneity within the junction fragments. Each of the cloned junction fragments contained one of the following fragments: 0.553, 0.95, or 1.35 kilobase pairs (referred to as class I heterogeneity). Class II heterogeneity was defined as the presence of tandem duplications of class I fragments. In addition, a variable number (0 to 5) of a 0.2-kbp fragment (class III heterogeneity) was observed. Mapping of these fragments with partial XhoI digestions revealed that the class I and class III heterogeneous fragments were adjacent. The DNA sequence of the smallest cloned L-S junction fragment was determined and analyzed. This junction fragment contained a single 0.553-kbp XhoI fragment and no copies of the 0.2-kbp fragment. The 0.553-kbp XhoI fragment was similar in structure to the a-sequences of herpes simplex virus types 1 and 2. In addition, a region of homology was found between the a sequences of herpes simplex virus types 1 and 2 and the 0.553-kbp XhoI fragment from the human cytomegalovirus junction.
人巨细胞病毒AD169株的基因组包含一个位于病毒DNA长（L）和短（S）成分交界处的异质性区域。使用限制性内切酶HaeII和XhoI对12个克隆的L-S连接片段进行了研究。异质性区域定位在单个HaeII限制性片段内。使用XhoI酶对该区域进行细分，揭示了连接片段内存在三种类型的异质性。每个克隆的连接片段包含以下片段之一：0.553、0.95或1.35千碱基对（称为I类异质性）。II类异质性定义为I类片段的串联重复。此外，观察到可变数量（0至5）的0.2-kbp片段（III类异质性）。用部分XhoI消化对这些片段进行图谱分析表明，I类和III类异质片段相邻。确定并分析了最小克隆的L-S连接片段的DNA序列。该连接片段包含一个单一的0.553-kbp XhoI片段，没有0.2-kbp片段的拷贝。0.553-kbp XhoI片段在结构上与1型和2型单纯疱疹病毒的a序列相似。此外，在1型和2型单纯疱疹病毒的a序列与人巨细胞病毒连接的0.553-kbp XhoI片段之间发现了一个同源区域。
