Tautz N, Meyers G, Stark R, Dubovi E J, Thiel H J
Institut für Virologie (FB Veterinärmedizin), Justus-Liebig-Universität Giessen, Germany.
J Virol. 1996 Nov;70(11):7851-8. doi: 10.1128/JVI.70.11.7851-7858.1996.
Cytopathogenic (cp) bovine viral diarrhea virus (BVDV) strains are generated in cattle persistently infected with noncytopathogenic (noncp) BVDV.cp BVDV strains are considered crucial for the development of fatal mucosal disease. Comparative analysis of cp and noncp BVDV strains isolated from one animal suffering from mucosal disease revealed that the genomes of the cp BVDV strain (CP7) and the corresponding noncp BVDV strain (NCP7) are highly homologous. However, only the genome of CP7 contains an insertion of 27 nucleotides in the NS2 coding region. The inserted sequence represents a duplication of bases 4064 to 4090 of the viral genome, located between the formerly neighboring nucleotides 4353 and 4354. Parts of the viral polyproteins of CP7 and NCP7 were expressed in the T7 vaccinia virus system. These studies revealed that the insertion identified in the CP7 genome is necessary and sufficient for the induction of NS2-3 cleavage. Since the expression of NS3 is strictly correlated to cp BVDV, the insertion identified in the genome of BVDV CP7 represents most likely the relevant mutation leading to the evolvement of CP7 from NCP7.
细胞病变性（cp）牛病毒性腹泻病毒（BVDV）毒株是在持续感染非细胞病变性（noncp）BVDV的牛体内产生的。cp BVDV毒株被认为对致命性黏膜病的发展至关重要。对从一头患有黏膜病的动物分离出的cp和noncp BVDV毒株进行比较分析发现，cp BVDV毒株（CP7）和相应的noncp BVDV毒株（NCP7）的基因组高度同源。然而，只有CP7的基因组在NS2编码区含有一个27个核苷酸的插入片段。插入的序列代表病毒基因组4064至4090位碱基的重复，位于先前相邻的核苷酸4353和4354之间。CP7和NCP7的部分病毒多聚蛋白在T7痘苗病毒系统中表达。这些研究表明，在CP7基因组中鉴定出的插入片段对于诱导NS2-3裂解是必要且充分的。由于NS3的表达与cp BVDV密切相关，在BVDV CP7基因组中鉴定出的插入片段很可能代表导致CP7从NCP7进化而来的相关突变。
