Argonaute and Trimmer generate Dicer-independent priRNAs and nucleate RNAi

ABSTRACT: RNA interference is involved in silencing of transposable and repetitive elements. How these elements are initially recognized by RNAi is a fundamental and unanswered question. We previously identified a class of Dicer-independent small RNAs, called primal small RNAs (priRNAs), in fission yeast. The mechanism by which Dicer-independent small RNAs are generated is not clear for any species. Here we reconstitute priRNA biogenesis in vitro and demonstrate that priRNAs can nucleate RNAi in vivo. We identify 3'-5' exonuclease Trimmer and show that Argonaute, loaded with longer RNA precursors, recruits Trimmer to generate the new 3' end. Next, we show that antisense priRNAs accumulate in rrp6M-NM-^T cells and nucleate RNAi at subset of protein coding genes in a Trimmer- and priRNA-dependent manner. Thus, Rrp6-mediated degradation of antisense transcripts and priRNA precursors protects the genome from spurious RNAi. Our results suggest that Argonaute association with random RNA degradation products triggers RNAi in a process of transcriptome surveillance. small RNA profiling in wild type S. pombe cells and in mutant cells

ORGANISM(S): Schizosaccharomyces pombe

SUBMITTER: Mario Halic 

PROVIDER: E-GEOD-38636 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress