TRANSCRIPTION ACTIVATION OF HIV 1

描述（改编自研究者摘要）：HIV编码一种新的 调节蛋白（达特），其对病毒生长很重要， 发病机制和潜伏期。 它编码一种HIV的转录刺激因子 基因表达。 一个顺式作用元件，称为TAR，位于长 末端重复序列（LTR），位于转录起始位点下游 在前病毒中，是达特反式激活所必需的。 机制 达特刺激HIV基因表达的机制仍不确定。 是 普遍认为，其主要行动是在 转录，虽然刺激的程度是由于 对转录起始或延伸的影响仍然没有解决。 然而，已经确定达特可以在伸长时刺激 水平，无论是在体内还是体外。 本建议的依据是 假设转录复合物在HIV启动子处形成， 达特缺失在延伸过程中是不稳定的，TAR RNA形成一个 用于结合达特和细胞蛋白质的支架，所述细胞蛋白质改变细胞的细胞结构。 复合物，以增加其延伸能力。 校长 拟议合作的目的是探讨机制， 这一过程的基础，并发现身份的 由达特募集到复合物中的转录因子， TAR. 为此，该项目将利用体外转录 三种类型的系统;（i）常规HeLa细胞核提取物 响应达特的DNA模板，（ii）其中DNA模板 固定在琼脂糖珠上， 和（iii）由携带异源的模板指导的系统 衰减器信号可以引起聚合酶暂停和终止。

DESCRIPTION (adapted from investigator's abstract): HIV encodes a novel regulatory protein, (Tat), which is important for virus growth, pathogenesis and latency. It encodes a transacting stimulator of HIV gene expression. A cis acting element called TAR, located in the long terminal repeat (LTR), downstream of the transcription initiation site in the provirus, is required for transactivation by Tat. The mechanism whereby Tat stimulates HIV gene expression remains uncertain. It is generally accepted that its major action is at the level of transcription, although the extent to which the stimulation is due to effects on transcriptional initiation or elongation is still unresolved. However, it is well-established that Tat can stimulate at the elongation level, both in vivo and in vitro. The present proposal is based on the hypothesis that transcription complexes formed at the HIV promoter in the absence of Tat are unstable during elongation and that TAR RNA forms a scaffold for the binding of Tat and of cellular proteins which alter the complexes so as to increase their elongational competence. The principal objective of the proposed collaboration is to explore the mechanism underlying this process and to discover the identity of the transcription factor(s) that are recruited into the complex by Tat and TAR. To this end, the project will exploit in vitro transcription systems of three types; (i) a conventional HeLa cell nuclear extract that responds to Tat, (ii) a system in which the DNA template is immobilized on agarose beads so that components can be added and removed at will, and (iii) a system directed by templates carrying heterologous attenuator signals that can cause polymerase pausing and termination.