Tada H, Lashgari M S, Khalili K
Department of Biochemistry and Molecular Biology, Jefferson Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania 19107.
Virology. 1991 Jan;180(1):327-38. doi: 10.1016/0042-6822(91)90037-c.
The human neurotropic papovavirus JCV contains sequences within the two 98-bp tandem repeats which play a key role in glial-specific transcription of the viral early and late promoters. Previous analysis of the 98-bp sequence has delineated several protein-binding domains that are recognized by nuclear factors present in human brain cells. In the present study, by deletion mutation analysis, we have identified a region within each 98-bp repeat that reduces transcriptional activity of the JCV late promoter (JCVL). Using synthetic oligonucleotides spanning this region, designated "OP," we demonstrate that down-regulation of the JCVL promoter is associated with a pentanucleotide repeat sequence (AGGGAAGGGA) juxtaposed to the poly(dA) tract within the 98-bp tandem repeats. The OP sequence interacts specifically with a protein derived from glial nuclear extract and forms a major 56- to 60-kDa complex. Methylation interference experiment indicates that the three G residues proximal to the poly(dA) tract make major groove contacts with the protein. Single-base-pair substitution of these residues suggests that the complex can form in the presence of two of the three guanosyl residues. The possible role of this protein in regulating the JCV lytic cycle in concert with nearby regulatory elements within JCV promoter region is discussed.
人嗜神经乳头多瘤空泡病毒JCV在两个98bp的串联重复序列中含有一些序列，这些序列在病毒早期和晚期启动子的神经胶质特异性转录中起关键作用。先前对98bp序列的分析已经确定了几个蛋白质结合结构域，这些结构域可被人脑细胞中存在的核因子识别。在本研究中，通过缺失突变分析，我们在每个98bp重复序列中确定了一个区域，该区域可降低JCV晚期启动子（JCVL）的转录活性。使用跨越该区域的合成寡核苷酸，命名为“OP”，我们证明JCVL启动子的下调与98bp串联重复序列中与聚（dA）序列相邻的五核苷酸重复序列（AGGGAAGGGA）有关。OP序列与源自神经胶质核提取物的一种蛋白质特异性相互作用，并形成一个主要的56至60kDa复合物。甲基化干扰实验表明，聚（dA）序列近端的三个G残基与该蛋白质形成大沟接触。这些残基的单碱基对替换表明，在三个鸟苷残基中的两个存在时，复合物仍可形成。本文讨论了该蛋白质与JCV启动子区域内附近调控元件协同调节JCV裂解周期的可能作用。
