Montalvo E A, Shi Y, Shenk T E, Levine A J
Department of Molecular Biology, Princeton University, New Jersey 08544-1014.
J Virol. 1991 Jul;65(7):3647-55. doi: 10.1128/JVI.65.7.3647-3655.1991.
The Epstein-Barr virus BZLF1 gene product (ZEBRA) is a transcriptional activator whose expression in latently infected B cells is sufficient to induce the viral lytic cycle. Since there is no transcription of BZLF1 during latency, we carried out experiments to determine whether cis-acting negative elements in the BZLF1 promoter contribute to the lack of expression during this phase of the virus cycle. A series of deletion plasmids encompassing positions -551 to +14 of the BZLF1 promoter region were constructed and tested for the ability to drive chloramphenicol acetyltransferase (CAT) gene expression in the absence of inducing agents such as 12-O-tetradecanoylphorbol-13-acetate (TPA) and anti-immunoglobulin. Expression from the intact 551-bp region was very weak in most of the cell lines tested, but deletion of 165 bp from the 5' end caused a sevenfold increase in expression of CAT. Within these 165 bp, a minimal 48-bp region was sufficient to down regulate the expression of a simian virus 40/CAT fusion plasmid. The 48-bp negative element consists of 7-bp dyad symmetry elements separated by 27 bp. The rightmost half of the dyad symmetry element partially overlaps a region which has a 14-of-15-bp homology to the human cytoskeletal gamma-actin promoter.
爱泼斯坦-巴尔病毒BZLF1基因产物（ZEBRA）是一种转录激活因子，其在潜伏感染的B细胞中的表达足以诱导病毒裂解周期。由于潜伏期期间BZLF1不进行转录，我们开展实验以确定BZLF1启动子中的顺式作用负性元件是否导致病毒周期此阶段缺乏表达。构建了一系列包含BZLF1启动子区域-551至+14位的缺失质粒，并在不存在诸如12-O-十四烷酰佛波醇-13-乙酸酯（TPA）和抗免疫球蛋白等诱导剂的情况下，测试其驱动氯霉素乙酰转移酶（CAT）基因表达的能力。在大多数测试的细胞系中，完整的551 bp区域的表达非常弱，但从5'端缺失165 bp导致CAT表达增加了7倍。在这165 bp内，一个最小的48 bp区域足以下调猿猴病毒40/CAT融合质粒的表达。48 bp负性元件由间隔27 bp的7 bp二元对称元件组成。二元对称元件的最右半部分部分重叠了一个与人类细胞骨架γ-肌动蛋白启动子具有15个碱基中14个碱基同源性的区域。
