BioProject

Antisense ribosomal siRNAs (risiRNAs) downregulate pre-rRNAs through the nuclear RNAi pathway in Caenorhabditis elegans. More...

Antisense ribosomal siRNAs (risiRNAs) downregulate pre-rRNAs through the nuclear RNAi pathway in Caenorhabditis elegans. However, the biogenesis and regulation of risiRNAs remain obscure. Previously, we showed that 26S rRNAs are uridylated at the 3'-ends by an unknown terminal polyuridylation polymerase before the rRNAs are degraded by a 3' to 5' exoribonuclease SUSI-1(ceDIS3L2). There are three polyuridylation polymerases, CDE-1, PUP-2, and PUP-3, in C. elegans. Here, we found that CDE-1 is specifically involved in suppressing risiRNA production. CDE-1 localizes to perinuclear granules in the germline and uridylates both Argonaute-associated 22G-RNAs and 26S rRNAs at the 3'-ends. Immunoprecipitation followed by mass spectrometry (IP-MS) revealed that CDE-1 interacts with SUSI-1(ceDIS3L2). Consistent with those results, both CDE-1 and SUSI-1(ceDIS3L2) are required for the inheritance of RNAi. Therefore, this work identified a rRNA surveillance machinery of rRNAs that couples terminal polyuridylation and degradation. Overall design: In this study, we compared total small RNAs from (1) control animals; (2) cde-1(tm936) mutant. And we also compared the NRDE-3 associated small RNAs in (3) control embryo; (4) cde-1(tm936) embryo mutant; and (5)eri-1(mg366) L3 animals (6)eri-1(mg366);cde-1(tm936) L3 mutant; and HRDE-1 associated small RNAs in (7) control young adult animals; (8) cde-1(tm936) young adult mutant;and WAGO-1 associated small RNAs in (9) control young adult animals; (10) cde-1(tm936) young adult mutant;we also compared 26S rRNAs 3' tail-seq from (11,12) eri-1(mg366) embryo animals;(13,14)eri-1(mg366);cde-1(tm936) embryo animals and (15,16)eri-1(mg366);cde-1(tm936);cde-1::mCherry embryo animals, and compared 26S rRNAs 3' tail-seq from (17,18) eri-1(mg366) L3 animals;(19,20)eri-1(mg366);cde-1(tm936) L3 animals and (21,22)eri-1(mg366);cde-1(tm936);cde-1::mCherry L3 animals. Less...