A Dicer-Independent Route for Biogenesis of siRNAs that Direct DNA Methylation in Arabidopsis

ABSTRACT: DNA methylation directed by 24-nucleotide (nt) small interfering RNAs (siRNAs) plays critical roles in gene regulation and transposon silencing in Arabidopsis. Twenty-four-nt siRNAs are known to be processed from double-stranded RNAs by Dicer-like 3 (DCL3) and loaded into the effector Argonaute 4 (AGO4). Here we report a distinct class of siRNAs independent of DCLs (sidRNAs). sidRNAs are present as ladders of ~20 to 60nt in length, often having same 5' ends but differing in 3' ends by 1-nt steps. We further show that sidRNAs are associated with AGO4 and capable of directing DNA methylation. Finally we show that sidRNA production depends on AGO4 and distributive 3'-5' exonucleases. Our findings suggest an alternative route for siRNA biogenesis: precursor transcripts are bound by AGO4 and su

ORGANISM(S): Arabidopsis thaliana

SUBMITTER: Yijun Qi 

PROVIDER: E-GEOD-74398 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress