Silencing Mechanisms of siRNA and miRNA in Organisms

Gene silencing via microRNA(miRNA) expression and small interference RNA(siRNA) become important methods in for gene regulation.SiRNA-based RNA interference mediates the gene silencing by sequence complementary with target mRNA,whereas miRNA negatively regulates the gene expression at the post-transcriptional level through complementary sites at the 3′ untranslated regions of the target genes.The siRNA and miRNA regulation of gene expression has wide implications for the understanding of biology,as well as for disease etiology and treatment.Three sets of macromolecules,Dicers,Agos and 20 nt~25 nt RNA duplex,are introduced as the signature components of RNA silencing,two types of the classic silencing mechanisms of siRNA and miRNA are described.This review also compares the differences and discusses about the new arguments about the biological origins and silencing mechanisms of siRNA and miRNA.