Gong M, Jin J, Guarino L A
Department of Biology, Texas A&M University, College Station 77843-2128, USA.
Virology. 1998 May 10;244(2):495-503. doi: 10.1006/viro.1998.9116.
The protein product of the 39k gene of Autographa californica nuclear polyhedrosis virus is thought to be important for viral replication because of its association with the virogenic stroma and its role in activation of late gene expression Transient expression assays showed that addition of a DNA fragment encoding a 58-amino-acid polypeptide increased expression of a 39k reporter plasmid. This stimulation was dependent on cotransfection of a plasmid encoding IE1. Cotransfection of this gene, orf121, also stimulated ie1 expression, and the activation of ie1 was even more dramatic in the presence of IE1. These data suggested that ORF-121 stimulated 39k expression by upregulation of IE1 expression. Activation of 39k by ORF121 and the viral transcription factor IE2 was additive, while activation by ORF-121 and the apoptotic suppressor P35 was synergistic. Cotransfection of p39cat and pIE1 with plasmids encoding ORF121, IE2, and P35 stimulated 39cat expression more than 100-fold compared to cells transfected with only p39cat and pIE1. These data suggest that IE2 and ORF121 work by similar mechanisms and indirectly activate p39cat by increasing IE1 expression, while P35 increases 39cat expression by a different mechanism.
苜蓿银纹夜蛾核型多角体病毒39k基因的蛋白质产物被认为对病毒复制很重要，因为它与病毒发生基质相关联，并且在晚期基因表达的激活中发挥作用。瞬时表达分析表明，添加编码58个氨基酸多肽的DNA片段可增加39k报告质粒的表达。这种刺激依赖于编码IE1的质粒的共转染。该基因orf121的共转染也刺激了ie1的表达，并且在存在IE1的情况下，ie1的激活更为显著。这些数据表明，ORF - 121通过上调IE1表达来刺激39k表达。ORF121和病毒转录因子IE2对39k的激活是累加的，而ORF - 121和凋亡抑制因子P35的激活是协同的。与仅用p39cat和pIE1转染的细胞相比，将p39cat和pIE1与编码ORF121、IE2和P35的质粒共转染可刺激39cat表达超过100倍。这些数据表明，IE2和ORF121通过相似的机制起作用，并通过增加IE1表达间接激活p39cat，而P35通过不同的机制增加39cat表达。
