Miller P S, Ts'o P O
Division of Biophysics, School of Hygiene and Public Health, Johns Hopkins University, Baltimore, Maryland 21205.
Anticancer Drug Des. 1987 Oct;2(2):117-28.
The nucleotide sequences of genes contain information which can potentially be used to understand gene function and thus the biological properties of living organisms. This information can also be used to develop innovative new strategies for chemotherapy employing sequence-specific non-ionic oligonucleoside methylphosphonates. These oligonucleotide analogs, termed Matagen (an acronym for masking tape for gene expression), have the following properties: (1) the negatively charged phosphodiester linkage normally found in nucleic acids is replaced with a non-charged methylphosphonate group which confers increased lipophilicity to the oligomer; (2) the oligomers form stable hydrogen-bonded complexes with complementary nucleic acid sequences and retain the fidelity of Watson-Crick base pairing; (3) the lipophilic oligomers cross the cell membrane and also enter various organs of the body; and (4) the methylphosphonate backbone is inherently resistant to nuclease hydrolysis and thus oligomers are taken up intact from cell culture media and remain stable within the cellular environment. Two general strategies are used to block gene expression by Matagens at the mRNA level in mammalian cells. In the first approach, Matagens complementary to specific sites such as the initiation codon region are used to block translation of mRNA. Thus Matagens specifically inhibit translation of rabbit globin mRNA in cell-free systems and rabbit reticulocytes, and vesicular stomatitis virus protein synthesis, but not cellular protein synthesis, in virus-infected cells. In the second approach, Matagens complementary to splice junctions of precursor mRNAs are used to inhibit splicing. For example, a Matagen complementary to the donor splice junction of simian virus 40 (SV40) large T-antigen mRNA inhibits T-antigen synthesis in SV40-infected cells, and a Matagen complementary to the acceptor splice junction of herpes simplex virus (HSV) immediate early pre-mRNA 4 + 5 inhibits HSV replication in virus-infected cells. Two new types of Matagen, one derivatized with the photoactivatable cross-linking group psoralen and the other derivatized with a hydroxyl radical-producing group, EDTA-Fe(II), have been designed to improve the efficacy of Matagen and to overcome some of the problems inherent in physical binding of Matagens to complementary nucleic acids. The Matagen approach provides a new way to design antiviral and chemotherapeutic agents in a rational manner. It combines nucleic acid chemistry and chemotherapy to form a common basis for drug development as well as to provide fundamental knowledge about organisms and humans.
基因的核苷酸序列所包含的信息有可能用于理解基因功能，进而了解生物体的生物学特性。该信息还可用于开发采用序列特异性非离子型寡核苷甲基膦酸酯的创新化疗新策略。这些寡核苷酸类似物，称为Matagen（基因表达掩蔽带的首字母缩写），具有以下特性：（1）核酸中通常存在的带负电荷的磷酸二酯键被不带电荷的甲基膦酸基团取代，这赋予了寡聚物更高的亲脂性；（2）寡聚物与互补核酸序列形成稳定的氢键结合复合物，并保持沃森-克里克碱基配对的忠实性；（3）亲脂性寡聚物可穿过细胞膜并进入身体的各个器官；（4）甲基膦酸主链本身对核酸酶水解具有抗性，因此寡聚物可完整地从细胞培养基中摄取，并在细胞环境中保持稳定。在哺乳动物细胞中，有两种通用策略用于通过Matagen在mRNA水平阻断基因表达。在第一种方法中，与特定位点（如起始密码子区域）互补的Matagen用于阻断mRNA的翻译。因此，Matagen在无细胞系统和兔网织红细胞中特异性抑制兔珠蛋白mRNA的翻译，在病毒感染的细胞中特异性抑制水泡性口炎病毒蛋白的合成，但不抑制细胞蛋白的合成。在第二种方法中，与前体mRNA剪接连接点互补的Matagen用于抑制剪接。例如，与猴病毒40（SV40）大T抗原mRNA供体剪接连接点互补的Matagen可抑制SV40感染细胞中T抗原的合成，与单纯疱疹病毒（HSV）立即早期前体mRNA 4 + 5受体剪接连接点互补的Matagen可抑制病毒感染细胞中HSV的复制。已设计出两种新型Matagen，一种用可光活化的交联基团补骨脂素衍生化，另一种用产羟基自由基基团EDTA-Fe(II)衍生化，以提高Matagen的功效并克服Matagen与互补核酸物理结合中固有的一些问题。Matagen方法为合理设计抗病毒和化疗药物提供了一种新途径。它将核酸化学与化疗相结合，形成药物开发的共同基础，并提供有关生物体和人类的基础知识。
