DeMarchi J M, Lu Z Q, Rall G, Kupershmidt S, Ben-Porat T
Department of Microbiology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232.
J Virol. 1990 Oct;64(10):4968-77. doi: 10.1128/JVI.64.10.4968-4977.1990.
The sequences of several hundred nucleotides around the junctions between the L and S components in concatemeric DNA and in mature virion DNA were ascertained. The two ends of the mature genome (which are joined in concatemeric DNA) show no sequence homology. Several directly repeated elements are present near both ends of the genome. Furthermore, the last 82 nucleotides at the left end of the L component (and of the genome) are repeated in inverted form (inverted repeat within the L component [IRL]) approximately 350 to 600 nucleotides downstream (depending on the virus isolate) bracketing the UL2 component. A comparison between the sequences at the right and left ends of the L component of the genome showed patchy homology, probably representing a vestigial inverted repeat bracketing the L component (IRL). Furthermore, less than 5% of the genomes have an L component that is in the orientation opposite to that of most of the viral genomes, indicating that the vestigial IRL that brackets the UL sequence may be sufficient to mediate inversion of the L component in some of the genomes. On the other hand, the UL2 component, which is bracketed by a perfect IRL, does not invert to a greater extent than does the L component (if it inverts at all). Analysis of the nucleotide sequence at the concatemeric junction of three different pseudorabies virus isolates showed almost complete sequence conservation. The sequence and organization of the repeated elements in the different isolates were almost identical, despite their different histories and origins. The high degree of conservation of these repeated elements implies that they may fulfill an essential function in the life cycle of the virus.
确定了串联DNA和成熟病毒体DNA中L和S组分连接处周围数百个核苷酸的序列。成熟基因组的两端（在串联DNA中相连）没有序列同源性。在基因组两端附近存在几个直接重复元件。此外，L组分（以及基因组）左端的最后82个核苷酸以反向形式重复（L组分内的反向重复序列[IRL]），在下游约350至600个核苷酸处（取决于病毒分离株），包围着UL2组分。对基因组L组分左右两端序列的比较显示出斑驳的同源性，可能代表包围L组分的残余反向重复序列（IRL）。此外，不到5%的基因组其L组分的方向与大多数病毒基因组相反，这表明包围UL序列的残余IRL可能足以介导某些基因组中L组分的反向。另一方面，被完美IRL包围的UL2组分，其反向程度并不比L组分（如果它发生反向的话）更大。对三种不同伪狂犬病病毒分离株串联连接处核苷酸序列的分析显示出几乎完全的序列保守性。尽管不同分离株的历史和起源不同，但它们中重复元件的序列和组织几乎相同。这些重复元件的高度保守性意味着它们可能在病毒的生命周期中发挥重要作用。
