Kashanchi F, Sadaie M R, Brady J N
Laboratory of Molecular Virology, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, USA.
Virology. 1997 Jan 20;227(2):431-8. doi: 10.1006/viro.1996.8346.
The human immunodeficiency virus type 1 (HIV-1) transactivator Tat protein is essential for efficient viral gene expression and virus replication. The Tat core domain, a stretch of 12 amino acids between the cysteine-rich and the basic domain, is conserved in all HIV isolates and required for interaction with a number of cellular transcriptional regulatory proteins. Here we demonstrate that soluble peptide analogs of the Tat core domain (amino acid 36-50) are able to effectively block LTR transactivation. In transfection experiments, Tat core peptide analogs containing amino acid substitutions at position 41 and 44 inhibited Tat transactivation of an HIV-1 LTR-CAT reporter construct up to 80-fold. In contrast, inhibition of other promoters such as HTLV-I and CMV was approximately 2-fold. Tat peptide analog 36-50 (41/44) inhibited HIV virus replication by 85% in latently infected U1 cells induced with Tat. Furthermore, U1 cells treated with the Tat peptide 36-50 (41/44) analog showed markedly delayed virus transmission when cocultivated with parental U937 cells. Interestingly, while both short and long peptide analogs (amino acids 36-50 vs 36-72) inhibited Tat transactivation in transient assays, the short peptides were more effective inhibitors of virus replication in U1 cells. The Tat peptide analog did not decrease expression of cellular genes including beta-actin, GAPDH, and histone H2B.
人类免疫缺陷病毒1型（HIV-1）反式激活因子Tat蛋白对于有效的病毒基因表达和病毒复制至关重要。Tat核心结构域是富含半胱氨酸结构域和碱性结构域之间的一段12个氨基酸的序列，在所有HIV分离株中都保守，并且是与许多细胞转录调节蛋白相互作用所必需的。在此我们证明，Tat核心结构域（氨基酸36 - 50）的可溶性肽类似物能够有效阻断长末端重复序列（LTR）的反式激活。在转染实验中，在第41和44位含有氨基酸替代的Tat核心肽类似物抑制HIV-1 LTR - CAT报告基因构建体的Tat反式激活高达80倍。相比之下，对其他启动子如人嗜T细胞病毒I型（HTLV - I）和巨细胞病毒（CMV）的抑制约为2倍。Tat肽类似物36 - 50（41/44）在经Tat诱导的潜伏感染U1细胞中抑制HIV病毒复制达85%。此外，用Tat肽36 - 50（41/44）类似物处理的U1细胞与亲代U937细胞共培养时，显示出明显延迟的病毒传播。有趣的是，虽然短肽和长肽类似物（氨基酸36 - 50与36 - 72）在瞬时分析中均抑制Tat反式激活，但短肽在U1细胞中是更有效的病毒复制抑制剂。Tat肽类似物并未降低包括β-肌动蛋白、甘油醛-3-磷酸脱氢酶（GAPDH）和组蛋白H2B在内的细胞基因的表达。
