CONTROL OF 2-5A PATHWAY BY TS MUTANT OF VACCINIA

RNA周转是基因表达调控的核心;然而， 所涉及的机制还不清楚。 温度敏感 牛痘病毒突变体ts 22提供了一种遗传工具， 参与RNA周转的机制。 ts 22基因调控着 RNA在牛痘病毒感染的细胞中的稳定性。 TS 22病毒具有 败育晚期表型。 在非允许温度下，ts 22感染 在早期阶段正常进行;然而，在感染后8-10小时， RNA被降解，病毒感染中止（与外源性 干扰素治疗）。 我们的研究结果表明，RNA的降解是 这是由于2-5A依赖性RNase的激活。 2-5A合成酶-核糖核酸酶 途径，最初被发现作为抗病毒机制之一， 干扰素参与控制细胞内RNA周转， 生长、激素状态和分化。 调节2- 5A途径对于评估其在RNA降解中的作用具有价值。 我们 假设功能性ts 22基因产物使2-5A失活， 生产性感染期间。 2-5A途径的失活 功能性ts 22基因产物的表达，不依赖于病毒 感染，应该有助于阐明2-5A途径在细胞RNA中的作用 周转 我们拟研究ts 22基因对2-5A通路的调控作用 产品 这将通过确定ts 22的生长来实现。 牛痘病毒和rRNA切割（2-5A激活的指标） 系统）在非允许温度下，在电池中，2-5A 路径已被删除。 的组成型表达 将测试功能性ts 22基因产物的表达能力， 2-5A系统。 ts 22基因产物失活的步骤 将确定2-5A系统。 进一步使用表达所述蛋白的载体， 野生型ts 22基因或2-5A合成酶反义RNA应允许 评估2-5A系统在控制RNA降解中的作用 在细胞生长抑制期间，我们将确定这些载体的作用 对干扰素或糖皮质激素诱导的生长抑制和减少 在Daudi细胞中c-myc的表达。

RNA turnover is central to the regulation of gene expression; however, the mechanisms involved are not well understood. The temperature sensitive mutant of vaccinia virus, ts22, provides a genetic tool for elucidating mechanism(s) involved in RNA turnover. The ts22 gene regulates the stability of RNA in vaccinia virus infected cells. ts22 virus has an abortive late phenotype. At the non-permissive temperature, ts22 infection proceeds normally in the early stages; however, at 8-10 h post infection, RNA is degraded and virus infection aborted (independent of exogenous interferon treatment). Our results indicate that the degradation of RNA is due to the activation of 2-5A dependent RNase. 2-5A synthetase-RNase pathway, initially discovered as one of the antiviral mechanisms of interferon, has been implicated in controlling RNA turnover during cell growth, hormone status and differentiation. The ability to modulate the 2- 5A pathway would be of value in assessing its role in RNA degradation. We hypothesize that the functional ts22 gene product inactivates the 2-5A system during productive infection. Inactivation of the 2-5A pathway by expression of the functional ts22 gene product, independent of virus infection, should help elucidate the role of 2-5A pathway in cellular RNA turnover. We propose to study the modulation of 2-5A pathway by ts22 gene product. This will be accomplished by determining the growth of ts22 vaccinia virus and rRNA cleavage (an indicator of activation of the 2-5A system) at the non-permissive temperature, in cells in which the 2-5A pathway has been rendered inoperative. Constitutive expression of the functional ts22 gene product will be tested for its ability to inactivate the 2-5A system. The step(s) at which the ts22 gene product inactivates the 2-5A system will be determined. Further use of vectors expressing the wild type ts22 gene or 2-5A synthetase antisense RNA should permit the assessment of the role of the 2-5A system in controlling RNA degradation during cell growth inhibition and we will determine effect of these vectors on the interferon or glucocorticoid induced growth inhibition and reduction in c-myc expression in Daudi cells.