Fig. 1.

RNA silencing by small RNAs and their partner Argonaute family proteins in Drosophila, human, and mouse RNA. The expression level of 4 PIWI protein (PIWIL3) has been a discovery in humans. The mains roles of the mature sequences, RISC formation, piRNA precursors and target genes are summarized for miRNAs, and piRNAs. The correlation between piRNA and human PIWI protein has not yet been detect. Abbreviations: dsRNA, double-stranded RNA; esiRNA, endogenous small interfering RNA(siRNA); miRNA, microRNA; nt, nucleotide; piRNA, PIWI-interacting RNA; RISC, RNA-induced silencing complex; ssRNA, single-stranded RNA.