siRNA介导基因沉默的分子机器、作用模式和应用前景

siRNA(small interfering RNA)介导的基因沉默是细胞内监控寄生的遗传物质、沉默无用的信息模板和调节自然的时空转换的一种分子机制。它与体液免疫和细胞免疫一起形成了动物和人类机体中免疫系统的三大支柱，从不同水平上来对抗体内外有害物质的干扰和侵犯。现已清楚，大约22个核苷酸长的双链RNA能够通过不同途径，以序列特异的方式来高效地沉默含有同源序列的靶RNA分子。这一古老而又迷人的系统现已被公认为是鉴定基因功能、调控基因表达和改变基因表型的简单而有效的方法。可以预计，这一新颖的技术在不远的将来必将形成一条研究功能基因组学、探索信号通路和创造遗传缺陷模型的高速公路，并将开创一条预防和治疗人类疾病的新途径。

siRNA-MEDIATED GENE SILENCING

siRNA-mediated gene silencing is an intracellular molecule mechanism through which unwanted mRNAs can be silenced, aberrant RNAs can be degraded, and epigenetic elements such as virus can be suppressed. With antibodies or immune cells, these small RNAs constitute the complete immune system in mammals and humans, by which invasion and interference from the inside and outside of body can be counteracted. Now it is clear that about 22 nt double-stranded RNA (dsRNA) can effectively inhibit cognate RNA molecules in a sequence-specific manner. This ancient and fascinating system has been recognized as a powerful and useful tool to identify gene functions, to explore gene expression and to alter gene phenotype. The new technology promises to be a highway for studying functional genomics, clarifying signal pathways, and creating gene-deficient models, and to set up novel therapeutic strategies for the prevention and treatment of human diseases.