RNASE III MECHANISM OF DOUBLE STRANDED RNA CLEAVAGE

双链 RNA 切割的 RNA酶 III 机制

• 批准号: 6258846
• 负责人: Allen Whitall Nicholson
• 金额: $ 0.09万
• 依托单位: MICHIGAN STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-06-01 至 1999-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6258846
• 关键词: Invertebrata; animal tissue; biological products; biomedical resource; blood; communicable diseases; lipids

Double-stranded (ds) regions in RNA molecules provide targets for cleavage by cellular nucleases involved in the maturation and decay of cellular and viral RNAs. The long-range goal of this project is to determine the mechanism of enzymatic cleavage of dsRNA and its role in regulating cellular and viral RNA function and metabolism. We have developed an RNase III model wherein the dsRNA-binding motif stimulates cleavage through enhanced binding, and perhaps also through formation of the active enzyme dimer. RNase III activity is regulated by phosphorylation on serine, catalyzed by the bacteriophage T7 protein kinase. The T7 protein kinase also undergoes autophosphorylation with concomitant down-regulation of activity. RNase III is phosphorylated on at least two serines by the T7 protein kinase, which causes a 4-fold increase in catalytic activity. Knowing the sites of phosphorylation, in conjunction with enzymatic assays for dsRNA binding and cleavage, will provide new information on how phosphorylation regulates an RNA processing enzyme. The autophosphorylation of T7 on one or more serine residues is also of interest. The identified phosphoserines can then be changed to alanine, creating an autophosphorylation-resistant protein kinase which may exhibit sustained phosphorylation activity. Future biochemical studies will determine the other cellular targets of phosphorylation by the T7 protein kinase.

RNA分子中的双链（DS）区域为 涉及成熟和衰减的细胞核酸裂解的切割 细胞和病毒RNA。 这个项目的远程目标是 确定DSRNA酶促切割的机制及其在 调节细胞和病毒RNA功能和代谢。 我们有 开发了一个RNase III模型，其中dsRNA结合基序 通过增强的绑定刺激乳沟，也许也可以通过 活性酶二聚体的形成。 RNase III活性受调节 通过丝氨酸的磷酸化，由噬菌体T7催化 蛋白激酶。 T7蛋白激酶也发生 自磷酸化与活动的伴随下调。 T7蛋白在至少两个丝氨酸上磷酸化RNase III 激酶，导致催化活性增加4倍。 会心 磷酸化的位点，以及酶促测定 DSRNA绑定和乳沟将提供有关如何 磷酸化调节RNA加工酶。 这 T7在一个或多个丝氨酸残基上的自磷酸化也是 兴趣。 然后可以更改为鉴定的磷酸盐 丙氨酸，产生一种自磷酸化抗蛋白激酶 可能表现出持续的磷酸化活性。 未来 生化研究将确定其他细胞靶标 T7蛋白激酶的磷酸化。