Small RNA asymmetry in RNAi: function in RISC assembly and gene regulation.
RNAi is a conserved gene-specific regulatory mechanism, which silences target gene expression transcriptionally and post-transcriptionally. The RNAi machinery converts the sequence specific information of a long double stranded RNAs (dsRNAs) into small 21-22 nt long dsRNAs (siRNAs, miRNAs) which assemble into an effector complex, the RNA induced silencing complex (RISC). RISC assembly is asymmetric; one strand of an siRNA or a miRNA preferentially incorporates into the RNA-protein complex. Here, I review the rules of the asymmetric RISC formation and discuss their possible regulatory function in several steps in RNAi.
Hutvagner
Gyorgy
G
University of Dundee, School of Life Sciences, Division of Gene Regulation and Expression, Dundee DD1 4HN, UK. g.hutvagner@dundee.ac.uk
D000818:Animals; D001483:Base Sequence; D055592:Biophysical Phenomena; D001703:Biophysics; D005786:Gene Expression Regulation; D006801:Humans; D035683:MicroRNAs / Q000737:chemistry; D008956:Models, Chemical; D008957:Models, Genetic; D008969:Molecular Sequence Data; D034622:RNA Interference; D012323:RNA Processing, Post-Transcriptional; D012330:RNA, Double-Stranded / Q000737:chemistry; D034741:RNA, Small Interfering / Q000378:metabolism; D034743:RNA-Induced Silencing Complex / Q000502:physiology*; D013816:Thermodynamics; D014158:Transcription, Genetic
D035683:MicroRNAs; D012330:RNA, Double-Stranded; D034741:RNA, Small Interfering; D034743:RNA-Induced Silencing Complex