Douglass N J, Richardson M, Dumbell K R
Department of Medical Microbiology, University of Cape Town, South Africa.
J Gen Virol. 1994 Jun;75 ( Pt 6):1303-9. doi: 10.1099/0022-1317-75-6-1303.
DNA from isolates of monkeypox virus, when digested with the endonuclease PstI, gave fragment-size profiles which correlated with the geographic area from which the isolate originated. Although some of the differences were located subterminally in the genome, others mapped to the central conserved region. Further differentiation of the viral genomes was sought by analysis of a short region within the central conserved part of the genome that appeared to be a partially deleted counterpart of an intact 1024 bp open reading frame (ORF) present in variola and vaccinia virus genomes. We reasoned that this region would not be conserved by functional selection and would therefore be likely to show more variation between isolates of monkeypox virus. The deletions found in monkeypox virus isolates from Liberia and from Benin were almost the same as that which we had previously found in the Denmark strain. A much shortened ORF, potentially coding for a product of 133 amino acids, was retained in all three West African isolates, but three Zairean isolates each showed an identical series of small insertions and deletions which effectively abolish the ORF. Three deletions, present in all isolates, must pre-date the geographical separation of monkeypox virus lineages; other, presumably more recent, changes differ between the Zairean and West African isolates. In contrast, the base similarity was found to be more than 99% when all the monkeypox virus sequences were appropriately aligned. This, in a disrupted and presumably nonfunctional gene also indicates that the changes described are recent. It is suggested that insertions and deletions occur regularly during poxvirus DNA replication, but are preserved only in sequences that are not required for continued transmission in the natural host.
猴痘病毒分离株的DNA在用核酸内切酶PstI消化后，产生的片段大小图谱与分离株的地理来源相关。尽管有些差异位于基因组的亚末端，但其他差异则定位在中央保守区域。通过分析基因组中央保守部分内的一个短区域来进一步区分病毒基因组，该区域似乎是天花病毒和痘苗病毒基因组中存在的完整1024 bp开放阅读框（ORF）的部分缺失对应物。我们推断该区域不会通过功能选择而保守，因此可能在猴痘病毒分离株之间表现出更多变异。在来自利比里亚和贝宁的猴痘病毒分离株中发现的缺失与我们之前在丹麦毒株中发现的几乎相同。在所有三个西非分离株中都保留了一个大大缩短的ORF，可能编码一个133个氨基酸的产物，但三个扎伊尔分离株各自显示出一系列相同的小插入和缺失，有效地消除了该ORF。所有分离株中都存在的三个缺失一定早于猴痘病毒谱系的地理分离；其他可能更新的变化在扎伊尔和西非分离株之间有所不同。相比之下，当所有猴痘病毒序列进行适当比对时，发现碱基相似性超过99%。这在一个被破坏且可能无功能的基因中也表明所描述的变化是最近发生的。有人提出，插入和缺失在痘病毒DNA复制过程中经常发生，但仅保留在自然宿主中持续传播不需要的序列中。
