FACTORS INFLUENCING GENETIC TRANSCRIPTION INITIATION AND TERMINATION

影响基因转录起始和终止的因素

• 批准号: 6162402
• 负责人: R J CROUCH
• 金额: --
• 依托单位: EUNICE KENNEDY SHRIVER NATIONAL INSTITUTE OF CHILD HEALTH & HUMAN DEVELOPMENT
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/6162402
• 关键词: Escherichia coli; bacterial genetics; bacterial proteins; genetic transcription; human immunodeficiency virus; microorganism culture; murine leukemia virus; protein structure function; ribonuclease H; transposon /insertion element; virus genetics; virus protein; virus replication

The lab has continued studies on ribonucleases H. These enzymes are important for studying retroviral infections such as HIV as well as participation in therapy by means of antisense degradation of messenger RNA. In addition, these proteins occupy a unique niche in biochemical studies because of their ability to distinguish between RNA-DNA and RNA-RNA duplexes and degrade the RNA moiety of RNA-DNA hybrids. The details of this recognition and discrimination will advance our understanding of mechanisms by which proteins interact with nucleic acids. We have shown that two types of RNases H found in bacteria also are present in eukaryotes. These are important findings in light of their potential involvement in antisense drug therapy and for assessment of inhibitors of HIV RNase H on cell functions resulting from inhibition of cellular RNases H. We have also defined a non-RNase H domain present on one class of eukaryotic RNases H that binds to duplex RNAs, possibly as a means of regulation of RNase H activity. A common motif of 40 amino acids is present in all eukaryotic enzymes of this class including yeasts and human cells. Interestingly, a protein involved in translation of the polycistronic mRNA of cauliflower mosaic virus has the same motif and when placed in the context of the yeast RNase H, functions as an RNA duplex binding site. This points to recognition of duplex RNAs by each of these proteins. This non-RNase H domain provides an opportunity to define the sites on the protein, in both domains, that bind to RNA-DNA hybrids and, thereby, provide significant insight into protein nucleic acid interactions. RNase H of this class purified to homogeneity has the undesirable property of binding to various surfaces and can easily be lost. However, when duplex RNAs are included, the protein binds to them and remains soluble. This property can be exploited to determine the minimum size of duplex RNA necessary for binding and offers the potential for obtaining co-crystals of protein and nucleic acid for determination of the structure by X-ray crystallography.

该实验室继续研究核糖核酸酶H。 这些酶 对于研究艾滋病毒等逆转录病毒感染以及 通过反义降解信使参与治疗 核糖核酸 此外，这些蛋白质在生物化学中占据独特的位置， 研究，因为他们能够区分RNA-DNA和 RNA-RNA双链体并降解RNA-DNA杂合体的RNA部分。 的 这种承认和歧视的细节将促进我们的 理解蛋白质与核酸相互作用的机制 acids. 我们已经证明，在细菌中发现的两种类型的RNase H也是 存在于真核生物中。 这些都是重要的发现， 可能参与反义药物治疗和评估 HIV RNA酶H抑制剂对细胞功能的影响， 细胞RNA酶H. 我们还定义了一个非RNase H结构域存在于一类 真核生物RNA酶H，结合双链RNA，可能作为一种手段， RNase H活性的调节。 40个氨基酸的常见基序是 存在于这类的所有真核酶中，包括酵母， 人类细胞。 有趣的是，一种参与蛋白质翻译的蛋白质， 花椰菜花叶病毒的多顺反子mRNA具有相同的基序， 当置于酵母RNA酶H的环境中时，其功能为RNA 双链体结合位点。 这表明双链RNA的识别， 这些蛋白质。 这种非RNase H结构域提供了一个机会， 定义蛋白质上与RNA-DNA结合的两个结构域中的位点 杂交，从而提供了对蛋白质核酸 酸的相互作用 纯化至均一的这类RNase H具有 粘合到各种表面的不期望的性质，并且可以容易地 迷路了 然而，当包含双链RNA时， 并保持可溶性。 可以利用此属性来确定 结合所需的最小大小的双链RNA，并提供了潜在的 用于获得测定用蛋白质和核酸的共晶体 结构的X射线晶体学。