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， 其中涉及的机制还不是很清楚。温度敏感度 痘苗病毒突变体TS22为阐明 参与RNA周转的机制(S)。TS22基因调节 痘苗病毒感染细胞中RNA的稳定性。TS22病毒有一种 败育的晚期表型。在不允许的温度下，TS22感染 通常在早期阶段进行；然而，在感染后8-10小时， RNA降解，病毒感染中止(独立于外源 干扰素治疗)。我们的结果表明，RNA的降解是 由于依赖2-5A的核糖核酸酶的激活。2-5A合成酶核糖核酸酶 途径，最初被发现是作为抗病毒机制之一 干扰素被认为与控制细胞内RNA的周转有关 生长、激素状态和分化。能够调节2- 5A通路在评价其在RNA降解中的作用方面具有一定的价值。我们 假设功能性TS22基因产物使2-5A失活 系统在产生性感染期间。2-5A通路的失活 不依赖病毒的功能性TS22基因产物的表达 感染，应有助于阐明2-5A通路在细胞RNA中的作用 营业额。我们建议研究TS22基因对2-5A通路的调控 产品。这将通过确定TS22的增长来实现 痘苗病毒和rRNA裂解(2-5A激活的指标 系统)在不允许的温度下，在其中2-5A 路径已无法运行。的构造性表达 功能性TS22基因产物将被测试其灭活能力 2-5A系统。Ts22基因产物失活的步骤(S) 将确定2-5A系统。进一步使用表达 野生型TS22基因或2-5A合成酶反义RNA应允许 2-5A系统在控制RNA降解中的作用评估 在细胞生长抑制期间，我们将确定这些载体的效果 干扰素或糖皮质激素诱导的生长抑制和减少 C-myc在Daudi细胞中的表达。

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.