Boranophosphate DNA: RNA Hybrids as Probes of RNase H

描述(申请人提供)：低聚核苷硼磷酸盐 (BH3-ODN)是一类新的磷修饰的寡核苷酸 从天然DNA中化学地分离出来的，因为一个硼烷(BH-)基团取代了一个 磷酸二酯主链中的非桥氧。BH3--ODN更多 与天然DNA相比，亲脂性和对核酸酶的抵抗力更强；它们形成 Watson-Crick双链，并激活RNaseH介导的裂解 互补核糖核酸。硼磷酸盐加入天然的磷酸二酯，即 (一和二)硫酸盐，以及对核酸酶更敏感的2‘-F-阿拉伯核苷酸 酸，作为仅有的一类寡聚核苷酸本身可以 通过这种酶在RNA/寡核苷酸杂交物中协调mRNA的降解 RNaseH尽管最近在反义的用途上有所改进 寡核苷酸在体内的应用，还需要进一步的研究。世界银行的目标是 本论文的主要工作有：(1)合成了一系列含硼磷酸的寡核苷酸 和针对ras基因的混合骨架嵌合体；(2)评估 BH3-ODN和嵌合体激活Tnase H1的潜能；(3)评价 BH3--ODN的热力学、结构和生物物理性质 它们与RNA寡核苷酸杂交的动力学及对其的研究 BH3--ODN/RNA/RNaseH复合体中RNA的水解动力学(4)至 检测BH3-ODN在细胞中的穿透性和定位，以及其他 药理性质；(5)序列和结构的探讨 通过我们的化学对RNaseH专一性的要求。这个 硼磷酸盐提供了一个新的平台来探索 核糖核酸酶H催化的结构和序列。我们的总体目标是更好地 了解硼磷酸盐独特的化学和生物学特性 寡核苷酸，进一步了解核糖核酸酶的作用机制 H和反义药物。这些信息应该能让我们设计出更有效的 治疗癌症和病毒性疾病的反义药物。

DESCRIPTION (provided by applicant): The oligonucleoside boranophosphates (BH3--ODN) are a new class of phosphorus modified oligonucleotides that differ chemically from natural DNA in that a borane (BH-) group replaces one of the non-bridging oxygens in the phosphodiester backbone. BH3--ODN are more lipophilic and much more resistant to nucleases than natural DNA; they form Watson-Crick duplexes, and activate the Rnase H-mediated cleavage of complementary RNA. The boranophosphates join the natural phosphodiester, the (mono-and di-) thioates, and the more-nuclease-susceptible 2'-F-arabinonucleic acids, as the only classes of oligonucleotides that by themselves can orchestrate mRNA degradation in RNA/oligonucleotide hybrids via the enzyme RNase H. Despite recent improvements in the utility of antisense oligonucleotides in vivo, further progress is still needed. The goals of the proposed work are: (1) To synthesize a set of borano phosphate oligonucleotides and mixed-backbone chimeras targeted against the ras gene; (2) To evaluate the potential of BH3--ODN and chimeras to activate Tnase H1; (3) To evaluate biophysical properties of BH3--ODN including the thermodynamics, structure, and kinetics of their hybridization with RNA oligonucleotides and to study the kinetics of hydrolysis of RNA in BH3--ODN /RNA/Rnase H complexes. (4) To examine penetration of BH3-ODN and localization in cells, and other pharmacological properties; and (5) to probe the sequence and structural requirements for Rnase H specificity through our chemistry. The boranophosphates provide a new platform for probing the subtle effects of structure and sequence on RNase H catalysis. Our overall goals are to better understand the unique chemical and biological properties of boranophosphate oligonucleotides and gain further insight into the mechanism of action of RNase H and antisense agents. This information should allow us to design more potent antisense drugs for treating cancer and viral diseases.