Masuda T, el-Farrash M A, Kuroda M J, Harada S
Department of Biodefense and Medical Virology, Kumamoto University School of Medicine, Japan.
Virus Genes. 1993 Sep;7(3):241-53. doi: 10.1007/BF01702585.
To examine the 3' terminal processing of human immunodeficiency virus type 1 (HIV-1) transcripts and the effects of phorbol ester (TPA) on this processing, cellular RNAs from persistently infected T cells (MOLT-4) or promonocytes (U937), with or without TPA treatment, were analyzed. To map the 3' terminals of viral transcripts, the RNA samples were examined by RNase-protection assay with an HIV-1 long terminal repeat (LTR) antisense riboprobe. Without TPA treatment, the viral transcripts initiated at the cap site in 5' LTR and polyadenylated at poly(A) site in 3' LTR were dominantly detected in both types of cells. This analysis demonstrated that some occlusion mechanism inactivating the poly(A) site in 5' LTR might exist in these infected cells. After TPA treatment, we found a dramatic shift in the protected patterns of viral transcripts in MOLT-4 cells, while the shift in U937 cells was less dramatic. These results suggested that the primary factor(s) involved in the observed effect of TPA might be cellular. We also demonstrated that the shift in the protected patterns of viral transcripts was associated with increased steady-state levels of viral transcripts. These results indicated that the factors involved in the TPA-induced shift might have some relation to the trans-activation of HIV-1 by similar substances.
为了研究人类免疫缺陷病毒1型（HIV-1）转录本的3'末端加工以及佛波酯（TPA）对该加工过程的影响，我们分析了来自持续感染的T细胞（MOLT-4）或原单核细胞（U937）的细胞RNA，这些细胞经过或未经过TPA处理。为了绘制病毒转录本的3'末端图谱，我们使用HIV-1长末端重复序列（LTR）反义核糖探针通过核糖核酸酶保护试验检测RNA样本。在未进行TPA处理的情况下，在两种类型的细胞中均主要检测到从5'LTR中的帽位点起始并在3'LTR中的聚腺苷酸化位点进行聚腺苷酸化的病毒转录本。该分析表明，在这些感染细胞中可能存在某种使5'LTR中的聚腺苷酸化位点失活的封闭机制。TPA处理后，我们发现MOLT-4细胞中病毒转录本的受保护模式发生了显著变化，而U937细胞中的变化则不太明显。这些结果表明，参与观察到的TPA效应的主要因素可能是细胞性的。我们还证明，病毒转录本受保护模式的变化与病毒转录本稳态水平的增加有关。这些结果表明，参与TPA诱导的变化的因素可能与类似物质对HIV-1的反式激活有某种关系。
