Kretz-Remy C, Arrigo A P
Laboratoire du Stress Cellulaire, CNRS-UMR 106, Université Claude Bernard Lyon-I, Villeurbanne. France.
FEBS Lett. 1994 Sep 5;351(2):191-6. doi: 10.1016/s0014-5793(94)80103-7.
The long terminal repeat (LTR) of human immunodeficiency virus type 1 (HIV-1) is activated under different conditions including heat shock. By using transient transfection assay, we have compared the thermal activation of HIV-1 LTR to that of the promoter of the gene encoding the human stress protein hsp70 which is under the control of the heat shock transcription factor HSF. In these assays, the chloramphenicol acetyl transferase (Cat) gene was used as a reporter gene. Several parameters of the heat stress were analyzed such as the temperature, the duration of heat stress and that of the recovery period. Under every condition tested, we have found that the kinetics of activation of both promoters were very similar. In addition, both showed a similar inhibition by actinomycin D. These results were compared to those obtained with a DNA construct containing the early promoter of SV-40 virus coupled to the Cat gene. In this case, no heat-mediated accumulation of CAT protein was observed, indicating that the transcriptional activation of HIV-1 LTR by heat shock is specific. HIV-1 LTR contains two NF-kappa B binding elements, involved in the activation of this promoter during oxidative stress, which are sequence related to the heat shock element HSE. However, under all the heat shock conditions tested, we have been unable to detect the binding of any protein to kappa B elements, suggesting that this site is not directly involved in the thermal activation of HIV-1 LTR. These results indicate that the thermal transcriptional activation of HIV-1 LTR and hsp70 promoters occurs through different mechanisms that are triggered by similar heat shock conditions.
人类免疫缺陷病毒1型（HIV-1）的长末端重复序列（LTR）在包括热休克在内的不同条件下会被激活。通过瞬时转染试验，我们比较了HIV-1 LTR与人类应激蛋白hsp70编码基因启动子的热激活情况，hsp70基因启动子受热休克转录因子HSF调控。在这些试验中，氯霉素乙酰转移酶（Cat）基因用作报告基因。分析了热应激的几个参数，如温度、热应激持续时间和恢复期持续时间。在每个测试条件下，我们发现两个启动子的激活动力学非常相似。此外，两者都显示出对放线菌素D的类似抑制作用。将这些结果与用含有与Cat基因偶联的SV-40病毒早期启动子的DNA构建体获得的结果进行比较。在这种情况下，未观察到热介导的CAT蛋白积累，表明热休克对HIV-1 LTR的转录激活是特异性的。HIV-1 LTR包含两个NF-κB结合元件，在氧化应激期间参与该启动子的激活，它们与热休克元件HSE序列相关。然而，在所有测试的热休克条件下，我们都无法检测到任何蛋白质与κB元件的结合，这表明该位点不直接参与HIV-1 LTR的热激活。这些结果表明，HIV-1 LTR和hsp70启动子的热转录激活是通过由相似热休克条件触发的不同机制发生的。
