Sorting of small RNAs into Arabidopsis argonaute complexes is directed by the 5' terminal nucleotide.
Argonaute (AGO) proteins recruit small RNAs to form the core of RNAi effector complexes. Arabidopsis encodes ten AGO proteins and a large network of small RNAs. How these small RNAs are sorted into specific AGO complexes remains largely unknown. We have cataloged small RNAs resident in four AGO complexes. We found that AGO2 and AGO4 preferentially recruit small RNAs with a 5' terminal adenosine, whereas AGO1 harbors microRNAs (miRNAs) that favor a 5' terminal uridine. AGO5 predominantly binds small RNAs that initiate with cytosine. Changing the 5' terminal nucleotide of an miRNA predictably redirected it into a different AGO complex and alters its biological activity. These results reveal a role for small RNA sequences in assorting among AGO complexes. This suggests that specialization of AGO complexes might involve remodeling the 5' end-binding pocket to accept certain small RNA sequences, perhaps explaining the evolutionary drive for miRNAs to initiate with uridine.
Mi
Shijun
S
National Institute of Biological Sciences, No.7 Science Park Road, Zhongguancun Life Science Park, Beijing 102206, China.
Cai
Tao
T
Hu
Yugang
Y
Chen
Yemiao
Y
Hodges
Emily
E
Ni
Fangrui
F
Wu
Liang
L
Li
Shan
S
Zhou
Huanyu
H
Long
Chengzu
C
Chen
She
S
Hannon
Gregory J
GJ
Qi
Yijun
Y
D017360:Arabidopsis / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000378:metabolism*; D060565:Argonaute Proteins; D035683:MicroRNAs / Q000737:chemistry / Q000378:metabolism*; D009711:Nucleotides / Q000032:analysis / Q000378:metabolism; D018749:RNA, Plant / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D034741:RNA, Small Interfering / Q000378:metabolism; D022661:RNA, Untranslated / Q000302:isolation & purification / Q000378:metabolism*; D034743:RNA-Induced Silencing Complex / Q000737:chemistry / Q000378:metabolism*
C117457:AGO1 protein, Arabidopsis; C471209:AGO4 protein, Arabidopsis; D029681:Arabidopsis Proteins; D060565:Argonaute Proteins; D035683:MicroRNAs; D009711:Nucleotides; D018749:RNA, Plant; D034741:RNA, Small Interfering; D022661:RNA, Untranslated; D034743:RNA-Induced Silencing Complex