Inputs and outputs for chromatin-targeted RNAi.
Plant gene silencing is targeted to transposons and repeated sequences by small RNAs from the RNA interference (RNAi) pathway. Like classical RNAi, RNA-directed chromatin silencing involves the cleavage of double-stranded RNA by Dicer endonucleases to create small interfering RNAs (siRNAs), which bind to the Argonaute protein. The production of double-stranded RNA (dsRNA) must be carefully controlled to prevent inappropriate silencing. A plant-specific RNA polymerase IV (Pol IV) initiates siRNA production at silent heterochromatin, but Pol IV-independent mechanisms for making dsRNA also exist. Downstream of siRNA biogenesis, multiple chromatin marks might be targeted by Argonaute-siRNA complexes, yet mechanisms of chromatin modification remain poorly understood. Genomic studies of siRNA target loci promise to reveal novel biological functions for chromatin-targeted RNAi.
Department of Plant Biology, University of California, Davis, 1 Shields Avenue, Davis, CA 95616, USA. srchan@ucdavis.edu
Simon W-L
SW
Chan
D002843:Chromatin / Q000235:genetics / Q000378:metabolism*; D008954:Models, Biological; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000235:genetics* / Q000378:metabolism
D002843:Chromatin; D010940:Plant Proteins; D034741:RNA, Small Interfering