SODIUM-BUTYRATE TREATMENT OF CELLS LATENTLY INFECTED WITH HIV-1 RESULTS IN THE EXPRESSION OF UNSPLICED VIRAL-RNA
SODIUM-BUTYRATE TREATMENT OF CELLS LATENTLY INFECTED WITH HIV-1 RESULTS IN THE EXPRESSION OF UNSPLICED VIRAL-RNA
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DOI：
10.1006/viro.1993.1505
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发表时间：
1993-10-01
期刊：
影响因子：
3.7
通讯作者：
GONZALEZSCARANO, E
中科院分区：
文献类型：
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作者：
LAUGHLIN, MA;ZEICHNER, S;GONZALEZSCARANO, E
为了研究HIV-1前病毒潜伏期的潜在机制，我们生成了一组慢性HIV-1感染且稳定的长末端重复氯霉素乙酰转移酶（LTR-CAT）转染的TE671/RD细胞，并研究了它们的病毒产生和ltr驱动的报告基因表达。在淋巴细胞和单核细胞系中建立的逆转录病毒潜伏期组织培养模型表明，病毒产生的诱导与HIV-1特异性mRNA从单剪接和多剪接的优势转变为全长HIV-1 RNA的产生有关。我们在TE671/RD细胞中发现了类似的模式，但与U1和ACH2细胞相比，单独暴露于肉豆酸酯phorbol acetate （PMA）不能诱导病毒复制。相反，我们证明暴露于丁酸钠可以诱导全长病毒RNA的产生、病毒复制和ltr驱动的CAT表达。丁酸钠最直接的作用是抑制细胞组蛋白去乙酰化酶(s)，导致核小体的破坏，减轻基因表达的一个水平限制。与这一作用机制一致，我们进一步发现丁酸钠的作用：(i)与PMA和TNF-α协同作用；（ii）独立于蛋白质合成；（iii）不影响组成表达的肌酸磷酸激酶基因；（iv）不能映射到病毒LTR中的离散序列基序；和(v)不被n -乙酰半胱氨酸阻断，但（vi）被新生物素（细胞拓扑异构酶II的抑制剂）阻断。这些数据表明，在HIV-1潜伏期的非淋巴细胞模型中存在类似的受限病毒RNA表达模式。然而，这些结果表明，在这些细胞中有一个额外的病毒基因表达障碍，这是由丁酸钠克服。这些结果在组蛋白介导的HIV-1基因表达抑制的背景下进行了讨论。
To investigate potential mechanisms for HIV-1 proviral latency, we generated a set of chronically HIV-1 infected and stably long terminal repeat-chloramphenicol acetyl transferase (LTR-CAT)-transfected TE671/RD cells, and studied both their virus production and LTR-driven reporter gene expression. Established tissue culture models of retroviral latency in lymphoid and monocytoid cell lines have demonstrated that the induction of virus production is associated with a shift in HIV-1-specific mRNA from a predominance of singly and multiply spliced mRNA's to the production of full-length HIV-1 RNA. We found a similar pattern in TE671/RD cells, but in contrast to U1 and ACH2 cells, could not induce viral replication by exposure to phorbol myristate acetate (PMA) alone. We demonstrated instead that production of full-length viral RNA, viral replication, and LTR-driven CAT expression could be induced by exposure to sodium butyrate. The most proximate effect of sodium butyrate is inhibition of cellular histone deacetylase(s) which results in disruption of nucleosomes relieving one level of restriction to gene expression. Consistent with this mechanism of action, we further found that sodium butyrate's effects: (i) act synergistically with PMA and TNF-α; (ii) are independent of protein synthesis; (iii) do not affect the constitutively expressed creatine phosphokinase gene; (iv) do not map to a discrete sequence motif in the viral LTR; and (v) are not blocked byN-acetyl cysteine but (vi) are blocked by novobiocin, an inhibitor of cellular topoisomerase II. These data show that a similar pattern of restricted viral RNA expression exists in this nonlymphoid cellular model of HIV-1 latency. In contrast however, these results suggest that in these cells there is an additional block to viral gene expression, which is overcome with sodium butyrate. These results are discussed in the context of histone-mediated repression of HIV-1 gene expression.