Harrison G S, Maxwell F, Long C J, Rosen C A, Glode L M, Maxwell I H
Division of Medical Oncology, University of Colorado Health Sciences Center, Denver 80262.
Hum Gene Ther. 1991 Spring;2(1):53-60. doi: 10.1089/hum.1991.2.1-53.
Expression of a gene encoding the diphtheria toxin A (DT-A) fragment, controlled by tissue specific regulatory elements, has previously been used to kill selected cell populations. Here, we have examined the feasibility of controlling DT-A expression using regulatory systems from the human immunodeficiency virus (HIV-1) genome. Plasmids were constructed which express either DT-A or, as a model system, the luciferase (luc) reporter gene, under control of HIV-1 long terminal repeat (LTR) sequences (-167 to +80). While trans-activation by expression of the viral protein Tat was demonstrated, significant basal expression was observed. To reduce basal expression, cis-acting negative regulatory elements from the env region of the HIV-1 genome were inserted in the 3' untranslated region of both the luc and DT-A constructs. This dramatically reduced basal expression from the HIV LTR, and now both viral regulatory proteins Tat and Rev were required for maximal trans-activation. Such regulation of DT-A expression might be therapeutically applied to selectively kill HIV-infected cells in acquired immunodeficiency syndrome (AIDS) and AIDS-related complex (ARC).
由组织特异性调控元件控制的编码白喉毒素A（DT-A）片段的基因表达，此前已被用于杀死特定的细胞群体。在此，我们研究了使用来自人类免疫缺陷病毒（HIV-1）基因组的调控系统来控制DT-A表达的可行性。构建了在HIV-1长末端重复序列（LTR）（-167至+80）控制下表达DT-A或作为模型系统的荧光素酶（luc）报告基因的质粒。虽然证实了病毒蛋白Tat的表达可进行反式激活，但观察到了显著的基础表达。为了降低基础表达，将来自HIV-1基因组env区域的顺式作用负调控元件插入luc和DT-A构建体的3'非翻译区。这显著降低了HIV LTR的基础表达，现在病毒调控蛋白Tat和Rev都需要才能实现最大程度的反式激活。DT-A表达的这种调控可能在治疗上应用于选择性杀死获得性免疫缺陷综合征（AIDS）和AIDS相关综合征（ARC）中被HIV感染的细胞。
