Massung R F, Jayarama V, Moyer R W
Department of Immunology and Medical Microbiology, JHMHC, University of Florida College of Medicine, Gainesville 32610.
Virology. 1993 Dec;197(2):511-28. doi: 10.1006/viro.1993.1625.
Swinepox virus (SPV) contains a double-stranded cross-linked linear DNA genome of approximately 175 kilobase pairs with terminal inverted repetitions (TIRs) of 4.3 kb. The nucleotide sequence was determined for fragments from several regions of the genome including a 2.85-kb fragment from the central potentially conserved portion and two fragments within the presumed variable near-terminal regions which tend to be unique to a given poxvirus. The core sequence contains one partial and two complete open reading frames that are highly conserved and colinear with three contiguous ORFs within the HindIII D fragment of vaccinia virus (VV). The two near-terminal fragments, encompassing 14.2 and 3.6 kb, are respectively located 2.1 kb internal to the left and right cross-linked termini of the DNA and span the TIR junctions. The sequences encode 25 open reading frames including numerous proteins predicted to be membrane-bound or secreted in infected cells. Several ORFs unique to SPV were identified that may be involved in cell attachment, immune modulation, and pathogenesis including a novel poxvirus G protein-coupled receptor. In addition, several polypeptides encoded within the near-terminal regions of vaccinia virus DNA that function as host range or virulence factors are lacking within this region of swinepox virus including the VV growth factor, complement-binding protein, and ORFs C7L and K1L, associated with host range. The lack of these functional homologues could explain the characteristic attenuated phenotype and limited host range of SPV.
猪痘病毒(SPV)含有一个双链交联线性DNA基因组,大小约为175千碱基对,带有4.3 kb的末端反向重复序列(TIRs)。已测定了基因组几个区域片段的核苷酸序列,包括来自中央潜在保守部分的一个2.85 kb片段以及假定可变的近末端区域内的两个片段,这些片段往往是特定痘病毒所特有的。核心序列包含一个部分开放阅读框和两个完整开放阅读框,它们高度保守且与痘苗病毒(VV)HindIII D片段内的三个连续开放阅读框共线。两个近末端片段,分别为14.2 kb和3.6 kb,分别位于DNA左右交联末端内部2.1 kb处,跨越TIR连接点。这些序列编码25个开放阅读框,包括许多预计在感染细胞中为膜结合或分泌型的蛋白质。鉴定出了几个SPV特有的开放阅读框,它们可能参与细胞附着、免疫调节和发病机制,包括一种新型痘病毒G蛋白偶联受体。此外,痘苗病毒DNA近末端区域内编码作为宿主范围或毒力因子的几种多肽在猪痘病毒的该区域中不存在,包括VV生长因子、补体结合蛋白以及与宿主范围相关的开放阅读框C7L和K1L。这些功能同源物的缺失可以解释SPV的特征性减毒表型和有限的宿主范围。