Dataset Information

ARGONAUTE10 promotes the degradation of miR165/6 through the SDN1 and SDN2 exonucleases in Arabidopsis [AGO10OE]

ABSTRACT: The degradation of small RNAs in plants and animals is associated with small RNA 3’ truncation and 3’ uridylation and thus relies on exonucleases and nucleotidyl transferases. Argonaute proteins associate with small RNAs in vivo and are essential for not only the activities but also the stability of small RNAs. Arabidopsis ARGONAUTE10 (AGO10) maintains stem cell homeostasis in meristems by sequestration of miR165/6, a conserved miRNA acting through AGO1. Here, we report that AGO10 reduces miR165/6 accumulation by enhancing its degradation. This is contrary to the stabilizing effect of all known argonaute proteins on their associated small RNAs. We show that SMALL RNA DEGRADING NUCLEASES (SDNs) are responsible for miRNA 3’ truncation in general and AGO10 promotes the degradation of miR165/6 by SDNs. Our work identifies the exonucleases responsible for miRNA 3’ truncation in vivo and uncovers a mechanism of specificity determination in miRNA turnover. This work, together with previous studies on AGO10, demonstrates that spatially regulated miRNA degradation underlies stem cell maintenance in plants.

ORGANISM(S): Arabidopsis thaliana

PROVIDER: GSE87348 | GEO | 2017/01/25

SECONDARY ACCESSION(S): PRJNA344469

REPOSITORIES: GEO

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Project description:It is largely unknown how microRNAs (miRNAs) are degraded in vivo or whether active miRNA turnover is critical to specific developmental processes. Arabidopsis ARGONAUTE10 (AGO10) maintains stem cell homeostasis in meristems by repression of miR165/6, a conserved miRNA acting through AGO1. Here, we report that AGO10, through its binding to miR165/6, reduces miR165/6 accumulation by enhancing its decay. We show that AGO10 promotes the 3’ truncation of miR165/6 by SMALL RNA DEGRADING NUCLEASES (SDNs) and that AGO10-bound miR165/6 is more susceptible to degradation by SDN1 than AGO1-bound miR165/6. Our work uncovers a mechanism that governs the stability of miRNAs, establishes the importance of spatially controlled miRNA decay in stem cell homeostasis, and sheds light on the diversification and specialization of Argonaute proteins. Both biogenesis and degradation contribute to the steady-state levels of microRNAs (miRNAs). miRNA degradation in both plants and animals is associated with 3’ truncation and 3’ uridylation, and in Arabidopsis, the nucleotidyl transferase HEN1 SUPPRESSOR1 is responsible for 3’ uridylation. The SMALL RNA DEGRADING NUCLEASE (SDN) family of 3’ to 5 exonucleases degrades short RNAs in vitro and limits the accumulation of miRNAs in vivo, but it is not known whether SDNs are responsible for the accumulation of 3’ truncated miRNA species in vivo. In addition, there has not been an example of active miRNA turnover being critical to specific developmental processes. Arabidopsis ARGONAUTE10 (AGO10) maintains stem cell homeostasis in meristems by sequestration of miR165/6, a conserved miRNA acting through AGO1. Here, we report that AGO10, through binding to miR165/6, reduces miR165/6 accumulation by enhancing its degradation. We show that SDNs are responsible for the generation of 3’ truncated miRNAs in vivo and AGO10 promotes the 3’ truncation of miR165/6 by SDNs. Our work uncovers a novel mechanism of miRNA degradation mediated by an argonaute protein, which contrasts the known stabilizing effects of most AGO proteins on their associated miRNAs. This work, together with previous studies on AGO10, demonstrates that spatially regulated miRNA degradation underlies stem cell maintenance in plants.

Dataset Information

ARGONAUTE10 promotes the degradation of miR165/6 through the SDN1 and SDN2 exonucleases in Arabidopsis [AGO10OE]

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