Department of Applied Veterinary Sciences, United Graduate School of Veterinary Sciences, Gifu University, Gifu 501-1193, Japan.
Virology. 2010 May 10;400(2):259-70. doi: 10.1016/j.virol.2010.02.012. Epub 2010 Mar 2.
Equine herpesvirus 1 (EHV-1) bacterial artificial chromosome clone (Ab4p BAC) was established based on neuropathogenic strain Ab4p. ORF37 encoding UL24 was replaced with a selection cassette, rpsL-neo gene, to produce an ORF37 deletion mutant, Ab4pORF37. Transfection of RK-13 cells with Ab4pORF37 genome DNA produced infectious virus, indicating that ORF37 is not essential for EHV-1 replication in cell culture. Deletion of ORF37 had no effect on the transcript expression of neighboring genes, ORF36 and ORF38, and the growth activity in MDBK cells. Ab4pDeltaORF37 lost neuropathogenicity in CBA/N1 mice as indicated by the absence of any neurological disorders and death. The growth of Ab4pDeltaORF37 in cultivated neural cells was one order of magnitude lower than that of parental and revertant viruses. These results indicated that the ORF37 is a neuropathogenicity determinant of EHV-1 in the mouse encephalitis model.
马疱疹病毒 1 型 (EHV-1) 细菌人工染色体克隆 (Ab4p BAC) 是基于神经致病性菌株 Ab4p 建立的。ORF37 编码 UL24 的基因被替换为一个选择盒，rpsL-neo 基因，从而产生 ORF37 缺失突变体 Ab4pORF37。将 Ab4pORF37 基因组 DNA 转染 RK-13 细胞产生了感染性病毒，表明 ORF37 不是 EHV-1 在细胞培养中复制所必需的。ORF37 的缺失对邻近基因 ORF36 和 ORF38 的转录表达以及在 MDBK 细胞中的生长活性没有影响。Ab4pDeltaORF37 在 CBA/N1 小鼠中丧失了神经致病性，因为没有任何神经紊乱和死亡的迹象。Ab4pDeltaORF37 在培养的神经细胞中的生长速度比亲本和回复病毒低一个数量级。这些结果表明，ORF37 是 EHV-1 在小鼠脑炎模型中的神经致病性决定因素。
