Abstract
Argonaute (AGO) genes play central roles in RNA silencing. In this study, we analyzed Arabidopsis AGO2 and AGO5. Interestingly, the 5' nucleotide of small RNAs that associated with AGO2 was mainly adenine and that of AGO5 was mainly cytosine. Small RNAs that were abundantly cloned from the AGO2 fraction (miR163-LL and miR390) and from the AGO5 fraction (miR163-UL and miR390*) are derived from the single small RNA duplexes. Furthermore, each strand of the miR163-LL/miR163-UL duplex is selectively sorted to associate with AGO2 or AGO5 in a 5' nucleotide-dependent manner. These results clearly indicate that the mechanism selecting the guide strand is different between AGO proteins even from the identical small RNA duplex. AGO2 localized in the nucleus and in cytoplasm, while AGO5 localized throughout the cytoplasm.
